CA1069629A - Multi-band tuner with fixed broadband input filters - Google Patents
Multi-band tuner with fixed broadband input filtersInfo
- Publication number
- CA1069629A CA1069629A CA264,890A CA264890A CA1069629A CA 1069629 A CA1069629 A CA 1069629A CA 264890 A CA264890 A CA 264890A CA 1069629 A CA1069629 A CA 1069629A
- Authority
- CA
- Canada
- Prior art keywords
- band
- signal
- frequency
- lowest
- channel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/005—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
- H04B1/0053—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band
- H04B1/006—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band using switches for selecting the desired band
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/18—Modifications of frequency-changers for eliminating image frequencies
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
- H03J5/24—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
- H03J5/242—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection
- H03J5/244—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection used exclusively for band selection using electronic means
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/005—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/26—Circuits for superheterodyne receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Power Engineering (AREA)
- Multimedia (AREA)
- Superheterodyne Receivers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A tuner for receiving a broadcasting signal whose frequency band is divided into high and low channels is disclosed. In this case, the tuner has first and second filters whose pass bands are fixed, a switch changeably connected to one of output terminals of said first and second filters, said switch being so changed that upon receiving a low channel said switch is changed to one state to deliver only a signal belonging to the low channel in said broadcasting signal from said first filter while upon receiving a high channel said switch is changed to the other state to deliver only a sig-nal belonging to the high channel in said broadcasting signal from said second filter, a local oscillator, a mixer which is supplied with a local oscillation signal from said local oscillator and a signal from one of said first and second filters to be multiplied with each other, and means for deriving a signal from said mixer which belongs to a predetermined band as an intermediate frequency signal, and if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said broadcasting signal are taken as f1L
and f1H, respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L and f3H, respec-tively; the lowest and highest frequencies in the lowest band of said high channel of said broadcasting signal as f4L and f4H, respectively, the lowest and highest frequencies in the channel occupying the highest band of said high channel of said broadcasting signal as f12L and f12H, respectively; the band width of one channel of said broadcasting signal as fB; and the lowest fre-quency of the intermediate frequency signal as fL, respectively, and an upper heterodyne system is employed, the following conditions are satisfied;
....... (1) ....... (2) or ........ (3) and or ........ (4) while under the same assumption but a lower heterodyne system is employed, the following conditions are satisfied;
, , ..... (5) or ..... (6) and or
A tuner for receiving a broadcasting signal whose frequency band is divided into high and low channels is disclosed. In this case, the tuner has first and second filters whose pass bands are fixed, a switch changeably connected to one of output terminals of said first and second filters, said switch being so changed that upon receiving a low channel said switch is changed to one state to deliver only a signal belonging to the low channel in said broadcasting signal from said first filter while upon receiving a high channel said switch is changed to the other state to deliver only a sig-nal belonging to the high channel in said broadcasting signal from said second filter, a local oscillator, a mixer which is supplied with a local oscillation signal from said local oscillator and a signal from one of said first and second filters to be multiplied with each other, and means for deriving a signal from said mixer which belongs to a predetermined band as an intermediate frequency signal, and if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said broadcasting signal are taken as f1L
and f1H, respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L and f3H, respec-tively; the lowest and highest frequencies in the lowest band of said high channel of said broadcasting signal as f4L and f4H, respectively, the lowest and highest frequencies in the channel occupying the highest band of said high channel of said broadcasting signal as f12L and f12H, respectively; the band width of one channel of said broadcasting signal as fB; and the lowest fre-quency of the intermediate frequency signal as fL, respectively, and an upper heterodyne system is employed, the following conditions are satisfied;
....... (1) ....... (2) or ........ (3) and or ........ (4) while under the same assumption but a lower heterodyne system is employed, the following conditions are satisfied;
, , ..... (5) or ..... (6) and or
Description
.
~: ; ~ -i,i.
BACKGROUND OF THE INVENTION ..
15 Field of the Invention i.
- ~ ~ . ............................... . .
This invention relates generally to a tuner, and is directed more particularly to a tuner which can receive only a desired channel signal positively.
Descr1ption of the Prior Art . In general~ with a prior art VHF tuner for a television re-`
ceiver~ a broadcasting signal received by an antenna is supplied through .
a band pass filter at the input side, a high frequency amplifier circuit and r~ ~ a band pass filter of the intermediate stage to a mixer where the signal is ., .
;
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mixed with the local oscillation signal from a local oscillator and fre- -quency converted. me output signal from the mixer is deliver~l through an intermediate frequency band pass filter as an intermediate frequency signal.
Ih this case, the pass bands of the band pass filters are changed with the station selection operation at every c ~ so as to rem~ve un-necessary signals such as signals of other channels, which may cause image f ~ y signal obstacles, and seoondary high harma m c ccmponents prodNo~d in the amplifying element of the high ~requeocy amplifier circuit.
10As mentioned above, the prior art tuner is provided with the f ~ y selection circuit for changlng the pass band at every channel, so that the circuit ccnstruction thereof beoomes cc~plicated.
It is.an object of the invention to provide a tuner with simple :~
construction.
It is another object of the invention to provide a tuner which can receive only a desirel channel signal without a frequency selection ~;`
circuit swQtched at every channel.
According to an aspect of-the present inwention-, there is ~.
~ prowided a tuner which Lncludes first and ~*c~nd fil ~r means whose pass bands pass only signals belcnging to said low and high c~18, ~ respectl~ely;
a swltc]h~means changeably conrect0d to one of output ter- ~ .
minals of said~first and second filter means, said switch being so changed : ~-:that upon receiving a lcw channel said s~Qtch is changed to one s~te to deliver only a signal belonging to the low ch3nnel in said broadcasting signal from said first filter while upon r0c0iving a high channel said : :: swltch is chLDged to thle other state to deliver only a signal belonging to - ~ - the high ch~nnel in said b~oadoJsting signal from said seoond filter means;
~ ~ : a local oscillator means;
: a mixer means which is supplied with a local oscillation signal from said local oscillator means and a signal from one of said first and -~second filter means to be multiplied with each other; and ~4~
... . ~
10696z9 means for deliving a signal from said mixer which belongs to a predetermined band as an intermediate frequency signal~ wherein if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said bro.adcasting signal are taken as f1L and f1H J respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L and f3H respectively; the lowest and highest frequencies in ..
the lowest band of said high channel of said broadcasting signal as f4L and :.
f4H ~ respectively; the lowest and highest frequencies in the channel occupy-ing the highest band of said high channel of said broadcasting signal as f12L
and f12H ~ respectively; the band width of one channel of said broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL respectively~ and an upper heterodyne system is employed~ the follow- :
ing conditions are satisfied;
fL ~ 2 .. ~ . ... (1 ) . fL > f1 2H ~ f4H - - - (2) f < 2f 1L ~ f 3H ~ fB .
or .......... (3) ..
- fL > 2f3H ~ f1 H
;~: and 2f4L - f1 2H - fB
20 ~ fL ~ 2 or .......... (4) . fL ~ 2 while under the same assumption but a lower. heterodyne system is employed, the following conditions are satisfied;
~:~25~ : fL j f3L ~f1L ~ fL<f4L ~f3H ~ fL>f12L ~f4L - ------ (5) ' :
~ _ 5 --:
.
fL > 2 or fL ~ 1L ( f3H_ f1L) - fB ....... (6) and f12L. f4L - ( f12H - f4L) - fB
fL > 2 or fL ~ 2 .... ,,, (7) The other objects, features and advantages of the present invention will become apparent from the following description taken in con-junction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figs,1 and 2 are respectively systematic diagrams showmg examples of the tuner according to the present invention;
Fig,3 is a connection diagram showing a part of th0 examples shown in Figs,1 and 2; and Figs,4 to 8, inclusive, are diagrams used for explaining the frequency relation.
DESCRIPTION OF THE PRE_ERRED EMBODIMENTS
An embodiment of the tuner according to the invention will be hereinafter described with reference to Fig, 1. A broadcasting signal is received by an antenna 11 and then fed to first and second band pass filters 12L and 12H respectively. At the output sides of the band pass filters 12L
and 1 2H there is provided a switch SA which is switched to a contact L con-nected to the output side of the filter 1 2L and to a contact H connected to theoutput side of the filter 1 2H upon low channel and high channel receptions~
respectively. In this case~ the respective pass bands of the band pass filters - 1 2L and 1 2H are fixed such that the filter 1 2L passes therethrough only a signal belonging to low channels while the filter 1 2H passes therethrough only a signal belonging to high channels, For use with the Japanese VHF broad-casting signal reception, the pass band of the filter 12L is selected from ' -..
90 M~lz to 108 MHz and that of the filter 12H from 170 MHz to 222 MHz, respectively. Accordingly, from the switch SA there are derived only the low channel signals upon the low channel reception and only the high channel signals upon the high channel reception, respectively. The signal from the switch SA is fed through a high frequency amplifier circuit 13 to a mixer 15 which is supplied with the local oscillation signal from a local oscillator 16, In the mixer 15 the signals from the amplifier 13 and the local oscillator 16 are multiplied with each other to be frequency-converted, The output signal from the mixer 15 is fed to a band pass filter 17 whose pass band is fixed and from which an intermediate frequency signal belonging to a predetermined band is obtained, In this case, it is assumed that the lowest and highest fre-quencies of the lowest band occupying low channels are taken as f1L and f1H ~ respectively; the local oscillation frequency upon receiving the lowest channel of the low channels as f1; the lowest and highest frequencies of the highest band occupying the low channels as f3L and f3H J respectively; the local oscillation frequency upon receiving the highest channel of the low chan-nels as f3; the lowest and highest frequencies occupying the lowest band channel of high channels as f4L and f4H respectively; the local oscillation frequency upon receiving the lowest channel of the high channels as f4; the lowest and highest frequencies in the channel occupying the highest band of high channels as f12L and f12H ~ respectively; the local oscillation fre-quency upon receiving the highest channel of the high channels as f12; the band width of one channel of the broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL ~ respectively. In this case~ the following conditions are satisfied.
That is, in c ase of the upper heterodyne system, the following conditions are satisfied.
f ~? f3H ~ f1H ,,,,,,, (1) ,. - - - : : . ~ .
., .
~06~625~
f > f 12~1 f4H ..... (2) 2f 1 L ~ f 3H ~ fB
or O ... (3 ) fL ~ 3H `- 1 H
and fL ~ 4L _12__ fB
or ..... (4) fL > f 12H ~ f~H
Figs. 5 and 6 show diagrams used for explaining the case of the upper h0terodyne system. From Fig.5 it will be apparent that fL =
f1 ~ f1H And if fL ~ f1 ~ f1H is greater than (f3H ~ f1 ) the following condition is satisfied.
fL > f3H - f1 = f3H - (f1H - fL) If the condition (1 ) is satisfiedJ upon receiving the lowest channel of the low channelsJ the signal which is a multiplied signal of another channel signal of the low channels and the local oscillation signal of the fre-quency f1 at this time does not fall within the band of an intermediate frequency signal from fL to fH = flJ + fB and hence no image frequency signal obstacle is caused. At this timeJ since only the low channel signal is obtained from the switch SA . no image frequency signal obstacle caused by the high channel signal is of course caused. Further, since it is the assumption that the dif-ference betw een the frequency of the signal of each channel and the local oscillation frequency corresponding to the frequency of each channel signal is constant, if the condition (1 ) is satisfied~ no image frequency signal obstacle is similarly caused except the reception of the lowest channel of the low chan-nels. Similarly~ if the condition (2) is satisfied, when each channel of the high channels is received there is caused no image frequency signal obstacle due to other channel signals.
_ ~ _ . ~ ~ . , . - . . .. .
Upon receiving the low channels. only the low channel signal is obtained from the switch SA and hence the secondary high harmonic com-ponents produced in the high frequency amplifier circuit 13 are high harmonics of the low channel signals. At this time, as may be apparent from Fig. 6, if fH is lower than (2f1L - f3) or fL is higher than ~2f3H ~ f1)~ that is, fL + fB ~ 2f1L - f3 = 2f1L ~ (f3H + fL) or fL ~ 2f3H - f1 = 2f3H - (f1H ~ fL) and the condition (3) is satisfied, upon the reception of the low channels all the signals, which are multiplied signal of the secondary high harmonics of the low channel signals and the local oscillation signal, are outside the band of the intermediate frequency signal from fL to fH . Similarly, if the con-dition (4) is satisfied, upon the reception of high channels all the signals ~
which is a multiplied signal of the secondary high harmonics of the high chan-nel signals and the local oscillation signal, are outside the band of the inter-mediate frequency signal from fL to fH .
While, in case of the lower heterodyne system, the following conditions are satisfied.
fL ? f3L ~ f1L ' fL ~ f4L ~ f3H ' fL > f12L ~ f4L (5) f3L or fL < f 1L ( f3H- f1L ) ~ fB -- (6) and f ? --22L or fL < 4L ( f12H f4L ) ~ fB
Figs. 7 and 8 show diagrams used for explaining the case of the lower heterodyne system.
As may be apparent from Fig 7, if the following conditions f1 L > f3 = f3L fL
f3~l ~ f4 = f4L ~ fL
_ g _ ~696Z9 and f4L > f12 = f12L ~ fL
are satisfied and also the condition (5) is satisfied, the band of the local oscil-lation signal upon receiving the low channels, the band of the low channel broadcasting signals, the band of the local oscillation signal upon receiving the high channels and the band of the high channel broadcasting signals are not overlapped with one another.
Further~ since f3L > flL ~ the following condition (8) is obtained by satisfying the condition (5).
fL = f3L ~ f3 > f1 L ~ f3 ......... .... .. (8) Thus, as may be apparent from Fig.7, when each channel of the low channels is received the signal, which is a multiplied signal of the signal of the other channel of the low channels and the local oscillation signal at this time, is not fallen within the band of the intermediate frequency signal from fL to fH -Therefore, there is occurred no image frequency signal obstacle.
er~ gince f12L > f4L ~ the following condition (9) is obtained by satisfying the condition (5) fL ~ f 1 2L ~ f 1 2 ~ f~L - f 1 2 (9 ) Thus, when each channel of the high channels is received, no image frequency signal obstacle is caused similarly.
Further, upon the reception of low channels only the low chan-nel signal is derived from the switch SA, so that the secondary high harmonics produced ;n the high frequency amplifier circuit 13 are those of the low chan-nels. At this time~ as may be apparent from Fig,8~ if fL = f1L ~ f1 is higher than f3 and fH - f1H - f1 is lower than f1 ~ (f3H ~ f1L)~ that is, fL > f3 = f3L ~ fL or fL + fB ~; f1 -- (f3H f1 L) = f1 L fL ~ (f3H ~ f1 L) ` ~069629 .
and the condition (6) is satisfied, upon the reception of low channels all the signals~ which are a multiplied signal of the secondary high harmonics of the low channel signals and the local oscillation signal, are outside the band of the intermediate signal from fL to fH . Similarly, if the condition (7) is satisfied, upon the reception of high channels all the signals, which are a multiplied signal of the secondary high harmonics of high channel signals and the local oscillation signal are outside of the band of the intermediate signal from fL to f~l.
Table _ Channel Lowest Video Carrier Sound Carrier Highest FrequencyFrequencyFrequency Frequency (MHz) (MHz) (MHz) (MHz) 0 1 90 ( = f1 L) 91.25 95.75 96 ( = f1 H) q 2 96 97.25 101 .75 102 ~1 3 102 ( = f3L) 103.25 107.75 108 ( = f3H) 4 1 70 ( = f4L) 1 71 .25 1 75.75 176 ( 2f4H) 1 76 177.25 1 81.75 1 82 6 182 183.25 1 87.75 188 7 188 189.25 193.75 194 c 8 192 193.25 197.75 198 9 1 98 199.25 203.75 204 204 205.25 209.75 21 0 1 I 210 211 .25 21 5 75 21 6 12 216 ( =f12L) 217.25 221.75 222 ( =f12H
. .
The tuner for receiving the Japanese VHF broadcasting signal at present will be described practically. The state of the respective channel signals of the VHF broadcasting signals in Japan is shown in Fig 4, and the practical frequencies thereof are shown in the above Table, where fB = 6 MHz Firstly, the case of the upper heterodyne system is considered.
From the condition (1), the following condition (10) is derived;
f ~ f3H ~ f1H = 6 MHz ................................................................. (10) From the condition (2), the following condition (11) is derived;
fL ~ f 12H 4H = 23 MHz . . . (11) From the condition (3), the following condition (12) is derived;
fL < 1L 3H fB = 33 MH
or ..... (12) fL > 3H f1H = 60 MHz and from the condition (4), the following condition (13) is derived.
fL ~ - 4L 12H fB = 56 MH
or ...... (13) fL > 12H f4H = 134 MHz Accordingly, the following condition (14) will satisfy all the conditions (10) to (13).
23 MHz ~ fL ~ 33 MHz or ...... (14) fL > 134 MHz If the video intermediate frequency is taken as fp ~ fp ~ fL +
4 75 MHz . Therefore~ it is enough that fp satisfies the following condition (15).
27 75 MHz < fp < 37 75 MHz :~ . or ¦ ............................................................ (15) fp > 138.75 MH
.
Next, the case of t11e lower heterodyne system will be con-sidered .
From the condition (5), the following condition (16) is derived;
fL > f3L ~ f1L = 12 MHz L < f4L ~ f3H = 62 MHz ...... (16) L > f12L ~ f4L = 46 MHz From the condition (6), the following condition (17) is derived;
fL > ~ = 51 MHz or ,, . ( 17) fL ~ 1L (f3~l _ f1L ) - fB , 33 MH
and from the condition (7)7 the following condition (18) is derived, fL ~> 2 = 108 MHz or , ... (18) fL ~ 4L ( 12H f4L ) fB = 56 MHz Accordingly. the following condition (19) is considered to satisfy all the conditions (16~ to (18).
51 MHz ~ fL ~ 56 MHz ................. .. (19) If the video intermediate frequency fp is taken in consideration it is enough that fp will satisfy the following condition (20) since fp = fL +
1.25 MHz .
52.25 MHz ~ fp < 57,25 MHz ............. (20) Further, it is possible that when the low and high channels are received, the heterodyne system is made different.
Fig,2 is a block diagram of the invention which is used for the .: ~ . ' : :, 10696;~9 just above case. When the low channels are received, the upper heterodyne system is used, while when the high channels are received, the lower hetero-dyne system is used, or viceversa. For example, in the former case it is selected that the lowest frequency fL of the intermediate frequency signal upon the reception of low channels satisfies the conditions (1 ) and (3) and that thelowest frequency fL of the intermediate frequency signal upon the reception of high channels satisfies fL ~ f3L ~ f1L of the condition (5) and satisfies the condition (7), while in the latter case it is selected that the lowest fre-quency fL of the intermediate frequency signal upon the reception of high chan-nels satisfies the conditions (2) and (4), which is sufficient. Accordingly, in this case since the band of the intermediate frequency signal is differentupon~
the reception of low and high channels, as the band pass filter for the inter-mediate frequency signal, these are provided a band pass filter 1 7L for low channels and a band pass filter 12H for high channels, respectively, and the output signals from the filters 17L and 17H are changed by a switch SB which is ganged with the switch SA so as to deliver the intermediate signal~ as shown in Fig,2.
It may be considered that in the high frequency amplifier circuit 13~ there is generated a secondary distortion component which has the differ-ence frequency among the frequencies of each channel signal, the distortion component is not frequency-converted in the mixer 15 and delivered as the signal in the band of the intermediate frequency signal. However~ if the mixer 15 is formed of two transistors 18 and 19 connected differentially, a current source 20 is connected to the emitters of both the transistors 18 and 19 which converts the output signal from the high frequency amplifier 13 to a current, the local oscillator 16 is connected between the bases of both the transistors 18 and 19, and the band pass filter 17 for the intermediate frequency signal is connected to the collectors of the transistors 18 and 19, the secondary distor-tion components are cancelled. As a result~ no secondary distortion compo-nents are delivered through the band pass filter 17.
, ''~' 1~696Z9 As described above- according to the present invention, without the provision of frequency selection circuit switched at every chan-nel, the occurrence of any image frequency signal obstacle caused by the other channel signals is prevented and the occurrence of unnecessary signals caused by the secondary high harmonics is avoided. Thus, the tuner of the invention can receive only a desired channel signal with very simple construction When the lower heterodyne system is used, the band of broad-casting signals and the band of the local oscillation signalcan be also sepa-rated in this invention, so that even if the local oscillation signal may be leaked, this leaked signal does not act as jamming signal for other receivers located near In the above description, the Japanese VHF signal reception is exemplified, but it may be apparent that the same can be applied for any other VHF signal reception.
It will be apparent that many modifications and variations could be effected by one skilled in the art without departing from the spirits or scope of the novel concepts of the present invention .
~: ; ~ -i,i.
BACKGROUND OF THE INVENTION ..
15 Field of the Invention i.
- ~ ~ . ............................... . .
This invention relates generally to a tuner, and is directed more particularly to a tuner which can receive only a desired channel signal positively.
Descr1ption of the Prior Art . In general~ with a prior art VHF tuner for a television re-`
ceiver~ a broadcasting signal received by an antenna is supplied through .
a band pass filter at the input side, a high frequency amplifier circuit and r~ ~ a band pass filter of the intermediate stage to a mixer where the signal is ., .
;
. _ , .
.. ~. - . , - . : .
- ~ -: . , ,:: .. :, - : . . .
: ~ ~ , . ~: . . , - :
.
' ~ ,' , ., , ' .
` :~' ` . ` ':
,, '.' ~'''''-"'''`
mixed with the local oscillation signal from a local oscillator and fre- -quency converted. me output signal from the mixer is deliver~l through an intermediate frequency band pass filter as an intermediate frequency signal.
Ih this case, the pass bands of the band pass filters are changed with the station selection operation at every c ~ so as to rem~ve un-necessary signals such as signals of other channels, which may cause image f ~ y signal obstacles, and seoondary high harma m c ccmponents prodNo~d in the amplifying element of the high ~requeocy amplifier circuit.
10As mentioned above, the prior art tuner is provided with the f ~ y selection circuit for changlng the pass band at every channel, so that the circuit ccnstruction thereof beoomes cc~plicated.
It is.an object of the invention to provide a tuner with simple :~
construction.
It is another object of the invention to provide a tuner which can receive only a desirel channel signal without a frequency selection ~;`
circuit swQtched at every channel.
According to an aspect of-the present inwention-, there is ~.
~ prowided a tuner which Lncludes first and ~*c~nd fil ~r means whose pass bands pass only signals belcnging to said low and high c~18, ~ respectl~ely;
a swltc]h~means changeably conrect0d to one of output ter- ~ .
minals of said~first and second filter means, said switch being so changed : ~-:that upon receiving a lcw channel said s~Qtch is changed to one s~te to deliver only a signal belonging to the low ch3nnel in said broadcasting signal from said first filter while upon r0c0iving a high channel said : :: swltch is chLDged to thle other state to deliver only a signal belonging to - ~ - the high ch~nnel in said b~oadoJsting signal from said seoond filter means;
~ ~ : a local oscillator means;
: a mixer means which is supplied with a local oscillation signal from said local oscillator means and a signal from one of said first and -~second filter means to be multiplied with each other; and ~4~
... . ~
10696z9 means for deliving a signal from said mixer which belongs to a predetermined band as an intermediate frequency signal~ wherein if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said bro.adcasting signal are taken as f1L and f1H J respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L and f3H respectively; the lowest and highest frequencies in ..
the lowest band of said high channel of said broadcasting signal as f4L and :.
f4H ~ respectively; the lowest and highest frequencies in the channel occupy-ing the highest band of said high channel of said broadcasting signal as f12L
and f12H ~ respectively; the band width of one channel of said broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL respectively~ and an upper heterodyne system is employed~ the follow- :
ing conditions are satisfied;
fL ~ 2 .. ~ . ... (1 ) . fL > f1 2H ~ f4H - - - (2) f < 2f 1L ~ f 3H ~ fB .
or .......... (3) ..
- fL > 2f3H ~ f1 H
;~: and 2f4L - f1 2H - fB
20 ~ fL ~ 2 or .......... (4) . fL ~ 2 while under the same assumption but a lower. heterodyne system is employed, the following conditions are satisfied;
~:~25~ : fL j f3L ~f1L ~ fL<f4L ~f3H ~ fL>f12L ~f4L - ------ (5) ' :
~ _ 5 --:
.
fL > 2 or fL ~ 1L ( f3H_ f1L) - fB ....... (6) and f12L. f4L - ( f12H - f4L) - fB
fL > 2 or fL ~ 2 .... ,,, (7) The other objects, features and advantages of the present invention will become apparent from the following description taken in con-junction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figs,1 and 2 are respectively systematic diagrams showmg examples of the tuner according to the present invention;
Fig,3 is a connection diagram showing a part of th0 examples shown in Figs,1 and 2; and Figs,4 to 8, inclusive, are diagrams used for explaining the frequency relation.
DESCRIPTION OF THE PRE_ERRED EMBODIMENTS
An embodiment of the tuner according to the invention will be hereinafter described with reference to Fig, 1. A broadcasting signal is received by an antenna 11 and then fed to first and second band pass filters 12L and 12H respectively. At the output sides of the band pass filters 12L
and 1 2H there is provided a switch SA which is switched to a contact L con-nected to the output side of the filter 1 2L and to a contact H connected to theoutput side of the filter 1 2H upon low channel and high channel receptions~
respectively. In this case~ the respective pass bands of the band pass filters - 1 2L and 1 2H are fixed such that the filter 1 2L passes therethrough only a signal belonging to low channels while the filter 1 2H passes therethrough only a signal belonging to high channels, For use with the Japanese VHF broad-casting signal reception, the pass band of the filter 12L is selected from ' -..
90 M~lz to 108 MHz and that of the filter 12H from 170 MHz to 222 MHz, respectively. Accordingly, from the switch SA there are derived only the low channel signals upon the low channel reception and only the high channel signals upon the high channel reception, respectively. The signal from the switch SA is fed through a high frequency amplifier circuit 13 to a mixer 15 which is supplied with the local oscillation signal from a local oscillator 16, In the mixer 15 the signals from the amplifier 13 and the local oscillator 16 are multiplied with each other to be frequency-converted, The output signal from the mixer 15 is fed to a band pass filter 17 whose pass band is fixed and from which an intermediate frequency signal belonging to a predetermined band is obtained, In this case, it is assumed that the lowest and highest fre-quencies of the lowest band occupying low channels are taken as f1L and f1H ~ respectively; the local oscillation frequency upon receiving the lowest channel of the low channels as f1; the lowest and highest frequencies of the highest band occupying the low channels as f3L and f3H J respectively; the local oscillation frequency upon receiving the highest channel of the low chan-nels as f3; the lowest and highest frequencies occupying the lowest band channel of high channels as f4L and f4H respectively; the local oscillation frequency upon receiving the lowest channel of the high channels as f4; the lowest and highest frequencies in the channel occupying the highest band of high channels as f12L and f12H ~ respectively; the local oscillation fre-quency upon receiving the highest channel of the high channels as f12; the band width of one channel of the broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL ~ respectively. In this case~ the following conditions are satisfied.
That is, in c ase of the upper heterodyne system, the following conditions are satisfied.
f ~? f3H ~ f1H ,,,,,,, (1) ,. - - - : : . ~ .
., .
~06~625~
f > f 12~1 f4H ..... (2) 2f 1 L ~ f 3H ~ fB
or O ... (3 ) fL ~ 3H `- 1 H
and fL ~ 4L _12__ fB
or ..... (4) fL > f 12H ~ f~H
Figs. 5 and 6 show diagrams used for explaining the case of the upper h0terodyne system. From Fig.5 it will be apparent that fL =
f1 ~ f1H And if fL ~ f1 ~ f1H is greater than (f3H ~ f1 ) the following condition is satisfied.
fL > f3H - f1 = f3H - (f1H - fL) If the condition (1 ) is satisfiedJ upon receiving the lowest channel of the low channelsJ the signal which is a multiplied signal of another channel signal of the low channels and the local oscillation signal of the fre-quency f1 at this time does not fall within the band of an intermediate frequency signal from fL to fH = flJ + fB and hence no image frequency signal obstacle is caused. At this timeJ since only the low channel signal is obtained from the switch SA . no image frequency signal obstacle caused by the high channel signal is of course caused. Further, since it is the assumption that the dif-ference betw een the frequency of the signal of each channel and the local oscillation frequency corresponding to the frequency of each channel signal is constant, if the condition (1 ) is satisfied~ no image frequency signal obstacle is similarly caused except the reception of the lowest channel of the low chan-nels. Similarly~ if the condition (2) is satisfied, when each channel of the high channels is received there is caused no image frequency signal obstacle due to other channel signals.
_ ~ _ . ~ ~ . , . - . . .. .
Upon receiving the low channels. only the low channel signal is obtained from the switch SA and hence the secondary high harmonic com-ponents produced in the high frequency amplifier circuit 13 are high harmonics of the low channel signals. At this time, as may be apparent from Fig. 6, if fH is lower than (2f1L - f3) or fL is higher than ~2f3H ~ f1)~ that is, fL + fB ~ 2f1L - f3 = 2f1L ~ (f3H + fL) or fL ~ 2f3H - f1 = 2f3H - (f1H ~ fL) and the condition (3) is satisfied, upon the reception of the low channels all the signals, which are multiplied signal of the secondary high harmonics of the low channel signals and the local oscillation signal, are outside the band of the intermediate frequency signal from fL to fH . Similarly, if the con-dition (4) is satisfied, upon the reception of high channels all the signals ~
which is a multiplied signal of the secondary high harmonics of the high chan-nel signals and the local oscillation signal, are outside the band of the inter-mediate frequency signal from fL to fH .
While, in case of the lower heterodyne system, the following conditions are satisfied.
fL ? f3L ~ f1L ' fL ~ f4L ~ f3H ' fL > f12L ~ f4L (5) f3L or fL < f 1L ( f3H- f1L ) ~ fB -- (6) and f ? --22L or fL < 4L ( f12H f4L ) ~ fB
Figs. 7 and 8 show diagrams used for explaining the case of the lower heterodyne system.
As may be apparent from Fig 7, if the following conditions f1 L > f3 = f3L fL
f3~l ~ f4 = f4L ~ fL
_ g _ ~696Z9 and f4L > f12 = f12L ~ fL
are satisfied and also the condition (5) is satisfied, the band of the local oscil-lation signal upon receiving the low channels, the band of the low channel broadcasting signals, the band of the local oscillation signal upon receiving the high channels and the band of the high channel broadcasting signals are not overlapped with one another.
Further~ since f3L > flL ~ the following condition (8) is obtained by satisfying the condition (5).
fL = f3L ~ f3 > f1 L ~ f3 ......... .... .. (8) Thus, as may be apparent from Fig.7, when each channel of the low channels is received the signal, which is a multiplied signal of the signal of the other channel of the low channels and the local oscillation signal at this time, is not fallen within the band of the intermediate frequency signal from fL to fH -Therefore, there is occurred no image frequency signal obstacle.
er~ gince f12L > f4L ~ the following condition (9) is obtained by satisfying the condition (5) fL ~ f 1 2L ~ f 1 2 ~ f~L - f 1 2 (9 ) Thus, when each channel of the high channels is received, no image frequency signal obstacle is caused similarly.
Further, upon the reception of low channels only the low chan-nel signal is derived from the switch SA, so that the secondary high harmonics produced ;n the high frequency amplifier circuit 13 are those of the low chan-nels. At this time~ as may be apparent from Fig,8~ if fL = f1L ~ f1 is higher than f3 and fH - f1H - f1 is lower than f1 ~ (f3H ~ f1L)~ that is, fL > f3 = f3L ~ fL or fL + fB ~; f1 -- (f3H f1 L) = f1 L fL ~ (f3H ~ f1 L) ` ~069629 .
and the condition (6) is satisfied, upon the reception of low channels all the signals~ which are a multiplied signal of the secondary high harmonics of the low channel signals and the local oscillation signal, are outside the band of the intermediate signal from fL to fH . Similarly, if the condition (7) is satisfied, upon the reception of high channels all the signals, which are a multiplied signal of the secondary high harmonics of high channel signals and the local oscillation signal are outside of the band of the intermediate signal from fL to f~l.
Table _ Channel Lowest Video Carrier Sound Carrier Highest FrequencyFrequencyFrequency Frequency (MHz) (MHz) (MHz) (MHz) 0 1 90 ( = f1 L) 91.25 95.75 96 ( = f1 H) q 2 96 97.25 101 .75 102 ~1 3 102 ( = f3L) 103.25 107.75 108 ( = f3H) 4 1 70 ( = f4L) 1 71 .25 1 75.75 176 ( 2f4H) 1 76 177.25 1 81.75 1 82 6 182 183.25 1 87.75 188 7 188 189.25 193.75 194 c 8 192 193.25 197.75 198 9 1 98 199.25 203.75 204 204 205.25 209.75 21 0 1 I 210 211 .25 21 5 75 21 6 12 216 ( =f12L) 217.25 221.75 222 ( =f12H
. .
The tuner for receiving the Japanese VHF broadcasting signal at present will be described practically. The state of the respective channel signals of the VHF broadcasting signals in Japan is shown in Fig 4, and the practical frequencies thereof are shown in the above Table, where fB = 6 MHz Firstly, the case of the upper heterodyne system is considered.
From the condition (1), the following condition (10) is derived;
f ~ f3H ~ f1H = 6 MHz ................................................................. (10) From the condition (2), the following condition (11) is derived;
fL ~ f 12H 4H = 23 MHz . . . (11) From the condition (3), the following condition (12) is derived;
fL < 1L 3H fB = 33 MH
or ..... (12) fL > 3H f1H = 60 MHz and from the condition (4), the following condition (13) is derived.
fL ~ - 4L 12H fB = 56 MH
or ...... (13) fL > 12H f4H = 134 MHz Accordingly, the following condition (14) will satisfy all the conditions (10) to (13).
23 MHz ~ fL ~ 33 MHz or ...... (14) fL > 134 MHz If the video intermediate frequency is taken as fp ~ fp ~ fL +
4 75 MHz . Therefore~ it is enough that fp satisfies the following condition (15).
27 75 MHz < fp < 37 75 MHz :~ . or ¦ ............................................................ (15) fp > 138.75 MH
.
Next, the case of t11e lower heterodyne system will be con-sidered .
From the condition (5), the following condition (16) is derived;
fL > f3L ~ f1L = 12 MHz L < f4L ~ f3H = 62 MHz ...... (16) L > f12L ~ f4L = 46 MHz From the condition (6), the following condition (17) is derived;
fL > ~ = 51 MHz or ,, . ( 17) fL ~ 1L (f3~l _ f1L ) - fB , 33 MH
and from the condition (7)7 the following condition (18) is derived, fL ~> 2 = 108 MHz or , ... (18) fL ~ 4L ( 12H f4L ) fB = 56 MHz Accordingly. the following condition (19) is considered to satisfy all the conditions (16~ to (18).
51 MHz ~ fL ~ 56 MHz ................. .. (19) If the video intermediate frequency fp is taken in consideration it is enough that fp will satisfy the following condition (20) since fp = fL +
1.25 MHz .
52.25 MHz ~ fp < 57,25 MHz ............. (20) Further, it is possible that when the low and high channels are received, the heterodyne system is made different.
Fig,2 is a block diagram of the invention which is used for the .: ~ . ' : :, 10696;~9 just above case. When the low channels are received, the upper heterodyne system is used, while when the high channels are received, the lower hetero-dyne system is used, or viceversa. For example, in the former case it is selected that the lowest frequency fL of the intermediate frequency signal upon the reception of low channels satisfies the conditions (1 ) and (3) and that thelowest frequency fL of the intermediate frequency signal upon the reception of high channels satisfies fL ~ f3L ~ f1L of the condition (5) and satisfies the condition (7), while in the latter case it is selected that the lowest fre-quency fL of the intermediate frequency signal upon the reception of high chan-nels satisfies the conditions (2) and (4), which is sufficient. Accordingly, in this case since the band of the intermediate frequency signal is differentupon~
the reception of low and high channels, as the band pass filter for the inter-mediate frequency signal, these are provided a band pass filter 1 7L for low channels and a band pass filter 12H for high channels, respectively, and the output signals from the filters 17L and 17H are changed by a switch SB which is ganged with the switch SA so as to deliver the intermediate signal~ as shown in Fig,2.
It may be considered that in the high frequency amplifier circuit 13~ there is generated a secondary distortion component which has the differ-ence frequency among the frequencies of each channel signal, the distortion component is not frequency-converted in the mixer 15 and delivered as the signal in the band of the intermediate frequency signal. However~ if the mixer 15 is formed of two transistors 18 and 19 connected differentially, a current source 20 is connected to the emitters of both the transistors 18 and 19 which converts the output signal from the high frequency amplifier 13 to a current, the local oscillator 16 is connected between the bases of both the transistors 18 and 19, and the band pass filter 17 for the intermediate frequency signal is connected to the collectors of the transistors 18 and 19, the secondary distor-tion components are cancelled. As a result~ no secondary distortion compo-nents are delivered through the band pass filter 17.
, ''~' 1~696Z9 As described above- according to the present invention, without the provision of frequency selection circuit switched at every chan-nel, the occurrence of any image frequency signal obstacle caused by the other channel signals is prevented and the occurrence of unnecessary signals caused by the secondary high harmonics is avoided. Thus, the tuner of the invention can receive only a desired channel signal with very simple construction When the lower heterodyne system is used, the band of broad-casting signals and the band of the local oscillation signalcan be also sepa-rated in this invention, so that even if the local oscillation signal may be leaked, this leaked signal does not act as jamming signal for other receivers located near In the above description, the Japanese VHF signal reception is exemplified, but it may be apparent that the same can be applied for any other VHF signal reception.
It will be apparent that many modifications and variations could be effected by one skilled in the art without departing from the spirits or scope of the novel concepts of the present invention .
Claims (10)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A tuner for receiving a broadcasting signal whose frequency band is divided into high and low channels comprising:
a) first and second filter means whose pass bands pass only signals belonging to said low and high channels, respectively;
b) a switch means changeably connected to one of output terminals of said first and second filter means, said switch being so changed that upon receiving a low channel said switch is changed to one state to deliver only a signal belonging to the low channel in said broadcasting signal from said first filter while upon receiving a high channel said switch is changed to the other state to deliver only a signal belonging to the high channel in said broadcasting signal from said second filter means;
c) a local oscillator means;
d) a mixer means which is supplied with a local oscillation signal from said local oscillator means and a signal from one of said first and second filter means to be multiplied with each other; and e) means for deriving a signal from said mixer means which belongs to a predetermined band as an intermediate frequency signal, wherein if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said broadcasting signal are taken as f1L and f1H respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L
and f3H' respectively; the lowest and highest frequencies in the low-est band of said high channel of said broadcasting signal as f4L and f4H' respectively; the lowest and highest frequencies in the channel occupy-ing the highest band of said high channel of said broadcasting signal as f12L and f12H' respectively; the band width of one channel of said broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL, respectively. and an upper heterodyne system is employed, the following conditions are satisfied;
........ (1) ,,,,,,,. (2) or ...... (3) and or ....... (4) while under the same assumption but a lower heterodyne system is employed, the following conditions are satisfied;
.... (5) (6) and or ... (7)
a) first and second filter means whose pass bands pass only signals belonging to said low and high channels, respectively;
b) a switch means changeably connected to one of output terminals of said first and second filter means, said switch being so changed that upon receiving a low channel said switch is changed to one state to deliver only a signal belonging to the low channel in said broadcasting signal from said first filter while upon receiving a high channel said switch is changed to the other state to deliver only a signal belonging to the high channel in said broadcasting signal from said second filter means;
c) a local oscillator means;
d) a mixer means which is supplied with a local oscillation signal from said local oscillator means and a signal from one of said first and second filter means to be multiplied with each other; and e) means for deriving a signal from said mixer means which belongs to a predetermined band as an intermediate frequency signal, wherein if it is assumed that the lowest and highest frequencies in the lowest band of said low channels of said broadcasting signal are taken as f1L and f1H respectively; the lowest and highest frequencies of the highest band of the low channels of said broadcasting signal as f3L
and f3H' respectively; the lowest and highest frequencies in the low-est band of said high channel of said broadcasting signal as f4L and f4H' respectively; the lowest and highest frequencies in the channel occupy-ing the highest band of said high channel of said broadcasting signal as f12L and f12H' respectively; the band width of one channel of said broadcasting signal as fB; and the lowest frequency of the intermediate frequency signal as fL, respectively. and an upper heterodyne system is employed, the following conditions are satisfied;
........ (1) ,,,,,,,. (2) or ...... (3) and or ....... (4) while under the same assumption but a lower heterodyne system is employed, the following conditions are satisfied;
.... (5) (6) and or ... (7)
2. A tuner as claimed in claim 1 in which said signal delivering means is formed of two filters.
3. A tuner as claimed in claim 2 in which a second switch means is further changeably connected to output sides of said two filters.
4. A tuner for receiving a selected channel of a group of channels divided into a lower band comprising a plurality of lower band channels and a higher band comprising a plurality of higher band channels, said tuner comprising:
first filter means having a fixed pass band tuned to pass said lower band; second filter means having a fixed pass band tuned to pass said higher band; switching means connected to said first and second filter means to provide a signal path through a selective one of said first and second filter means;
a mixer connected to said signal path to receive the output signal thereof; a local oscillator connected to said mixer to supply thereto a frequency-converting signal to convert the frequency of said selected channel to an intermediate fre-quency band having a lowest frequency fL determined by the following conditions when the frequency of the frequency-converting signal is higher than the highest frequency of a selected channel:
and and one of the following:
or and one of the following:
or and the lowest frequency fL in the intermediate frequency band is determined by the following conditions when the frequency of the frequency-converting signal is lower than the lowest frequency of a selected channel:
and and and one of the following:
or and one of the following:
or where:
fB is the bandwidth of each channel;
f1L is the lower frequency in the lower band;
f3H is the higher frequency in the lowest band;
f4L is the lowest frequency in the highest band;
f12H is the highest frequency in the higher band.
first filter means having a fixed pass band tuned to pass said lower band; second filter means having a fixed pass band tuned to pass said higher band; switching means connected to said first and second filter means to provide a signal path through a selective one of said first and second filter means;
a mixer connected to said signal path to receive the output signal thereof; a local oscillator connected to said mixer to supply thereto a frequency-converting signal to convert the frequency of said selected channel to an intermediate fre-quency band having a lowest frequency fL determined by the following conditions when the frequency of the frequency-converting signal is higher than the highest frequency of a selected channel:
and and one of the following:
or and one of the following:
or and the lowest frequency fL in the intermediate frequency band is determined by the following conditions when the frequency of the frequency-converting signal is lower than the lowest frequency of a selected channel:
and and and one of the following:
or and one of the following:
or where:
fB is the bandwidth of each channel;
f1L is the lower frequency in the lower band;
f3H is the higher frequency in the lowest band;
f4L is the lowest frequency in the highest band;
f12H is the highest frequency in the higher band.
5. A tuner as claimed in claim 4 comprising high frequency amplifier means connected in cascade between said first and second filter means and said mixer, .
6. A tuner as claimed in claim 5 in which said switching means is connected to output terminals of each of said first and second filter means and comprises an output terminal connected to said high frequencyamplifier means to supply to said amplifier means, selectively, either lower band signals that pass through said first filter means or higher band signals that pass through said second filter means.
7. A tuner as claimed in claim 4 further comprising two intermediate frequency filters connected in parallel to the output of said mixer.
8. A tuner as claimed in claim 7 comprising a second switch means changeably connected to output sides of said two intermediate frequency filters.
9. A tuner as claimed in claim 4 in which said first filter has a pass band with a lowest frequency of about 54MHz and a highest frequency of about 88MHz, and said second filter has a pass band with a lowest frequency of about 174MHz and a highest frequency of about 216MHz, and fL is greater than 88MHz.
10. A tuner as claimed in claim 9 comprising an intermediate frequency band filter connected to said mixer and having a pass band not substantially greater in width than fB and having an upper pass band frequency less than 108MHz.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP50135500A JPS5823978B2 (en) | 1975-11-11 | 1975-11-11 | Chuyuna |
| US73927676A | 1976-11-05 | 1976-11-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069629A true CA1069629A (en) | 1980-01-08 |
Family
ID=26469337
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,890A Expired CA1069629A (en) | 1975-11-11 | 1976-11-04 | Multi-band tuner with fixed broadband input filters |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4132952A (en) |
| JP (1) | JPS5823978B2 (en) |
| AU (1) | AU502220B2 (en) |
| CA (1) | CA1069629A (en) |
| DE (1) | DE2651300A1 (en) |
| FR (1) | FR2331914A1 (en) |
| GB (1) | GB1560387A (en) |
| NL (1) | NL7612561A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1094653A (en) * | 1963-09-06 | 1967-12-13 | Plessey Uk Ltd | Improvements in or relating to superheterodyne receivers |
| US3333198A (en) * | 1965-12-29 | 1967-07-25 | Ampli Vision Corp | Television converter for catv system |
| US3639840A (en) * | 1969-11-28 | 1972-02-01 | Spencer Kennedy Lab Inc | Multicarrier transmission system |
| US3942120A (en) * | 1974-07-22 | 1976-03-02 | Texas Instruments Incorporated | SWD FM receiver circuit |
-
1975
- 1975-11-11 JP JP50135500A patent/JPS5823978B2/en not_active Expired
-
1976
- 1976-11-04 CA CA264,890A patent/CA1069629A/en not_active Expired
- 1976-11-08 GB GB46400/76A patent/GB1560387A/en not_active Expired
- 1976-11-08 AU AU19385/76A patent/AU502220B2/en not_active Expired
- 1976-11-10 FR FR7633990A patent/FR2331914A1/en active Granted
- 1976-11-10 DE DE19762651300 patent/DE2651300A1/en not_active Ceased
- 1976-11-11 NL NL7612561A patent/NL7612561A/en not_active Application Discontinuation
-
1978
- 1978-01-31 US US05/873,963 patent/US4132952A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU502220B2 (en) | 1979-07-19 |
| GB1560387A (en) | 1980-02-06 |
| US4132952A (en) | 1979-01-02 |
| JPS5259512A (en) | 1977-05-17 |
| DE2651300A1 (en) | 1977-05-18 |
| FR2331914A1 (en) | 1977-06-10 |
| AU1938576A (en) | 1978-05-18 |
| JPS5823978B2 (en) | 1983-05-18 |
| FR2331914B1 (en) | 1982-07-30 |
| NL7612561A (en) | 1977-05-13 |
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