WO1991016761A1 - A wide-band active rf-circuit - Google Patents

A wide-band active rf-circuit Download PDF

Info

Publication number
WO1991016761A1
WO1991016761A1 PCT/FI1991/000117 FI9100117W WO9116761A1 WO 1991016761 A1 WO1991016761 A1 WO 1991016761A1 FI 9100117 W FI9100117 W FI 9100117W WO 9116761 A1 WO9116761 A1 WO 9116761A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit
wide
changed
transistor
band
Prior art date
Application number
PCT/FI1991/000117
Other languages
French (fr)
Inventor
Juha Nikkanen
Original Assignee
Teleste Antenni Oy
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Teleste Antenni Oy filed Critical Teleste Antenni Oy
Publication of WO1991016761A1 publication Critical patent/WO1991016761A1/en

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
    • H03F1/083—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements in transistor amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/189—High frequency amplifiers, e.g. radio frequency amplifiers
    • H03F3/19—High frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
    • H03F3/191—Tuned amplifiers

Definitions

  • the present invention relates to a wide-band active radio frequency circuit, the amplification of which is controllable.
  • the networks also require amplifications of different magnitudes and thus conventionally several transistor stages and/or faders are connected in succession.
  • the change of amplification is effected by connecting e.g. circuits which shunt the transistor stages, wherein, however, the mechanical couplings arranged in the signal path are unreliable and may cause interference.
  • Using relays is undesirable since they are less reliable at high frequencies because of the mechanical parts they comprise and because fitting them into electronic solutions causes problems.
  • amplification can be changed by connecting adjustable amplifiers to the circuit, but the problem with this type of transistor stage is a varying impedance level, which must be compensated for by arranging matching circuits on the input and output sides of the transistor stage.
  • the aim of the invention is, therefore, to achieve a simple and reliable circuit which can advantageously be used in a cable television network.
  • This aim is achieved by means of the invention in such a way that the circuit's operating voltage is supplied through coupling elements, by means of which the polarity of the circuit's operating voltage can be changed if desired, in accordance with which the active element of the circuit operates either as an amplifier or as a voltage follower without the input or output poles changing .
  • the circuit relating to the invention has a simple and reliable structure, as a single transistor stage is advantageously used and can be controlled to be either an amplifier or a voltage follower. Thanks to this solution, no separate circuits shunting the amplifier or amplifiers connected in series are needed.
  • the transistor stage Tl shown in the figure is used as a dual-purpose stage, on the one hand as a wide-band amplifier stage and on the other as a voltage follower.
  • the function is selected on the coupling's simultaneously functioning keys SI - S4, by means of which the polarity of the circuit's operating voltage is changed.
  • the couplings can be realized in other ways, too, known to a person skilled in the art, e.g. by means of semiconductor couplings. In both functions the factors affecting the quality of the RF-signal, such as the distortion properties and the noise performance as well as the impedance level remain essentially the same. In the voltage follower function the transducer loss is as small as possible.
  • the keys SI - S4 of the coupling element are in position 1.
  • the NPN-transistor stage functions as an ordinary feedback common-emitter stage.
  • the amplification is determined by the feedback elements LC and RC,.when the PIN-diode pair D1-D2 is made conductive by forward direct current +12 V on key S4.
  • the circuit's capacitances and inductances have, in accordance with the practice in the field, an RF-signal path from input RF IN to output RF OUT, which is separated from the transistor's direct current circuits.
  • the voltage follower function when the coupling's keys are in position 2, the direction of the collector current of transistor Tl is reversed, that is, from emitter to collector.
  • the value of the collector current is limited by means of the resistance 1.5 kohm, connected through key S3, to about 20mA.
  • the PIN-diodes in the emitter circuit are then in a blocked state and no direct current flows through the circuit, and thus they create a sufficiently high impedance from the emitter to the ground.
  • This voltage follower functions in a different way than the conventional solution, and thus in the present solution the collector current RF OUT follows the base voltage RF IN.
  • the circuit relating to the invention can advantageously be used in a cable television network. Tests carried out with the circuit have shown the circuit to function in accordance with the targets set for it.

Abstract

The present invention relates to a wide-band RF-circuit of which it is characteristic that the circuit's operating voltage is supplied through coupling elements (S1-S4), by means of which the polarity of the circuit can be changed if desired, in accordance with which the transistor stage (T1) functions either as an amplifier or as a voltage follower without the input or output poles (RF IN, RF OUT) of the RF-signal being changed.

Description

A WIDE-BAND ACTIVE RF-CIRCUIT
The present invention relates to a wide-band active radio frequency circuit, the amplification of which is controllable.
In cable television networks, simple transistor stages are often used as amplifiers. In such cases a wide-band amplifier is required, that is, one which functions within several octaves of the frequency. A network operating at a frequency of several MHz requires as short and interference-free signal paths as possible.
The networks also require amplifications of different magnitudes and thus conventionally several transistor stages and/or faders are connected in succession. According to the prior art, the change of amplification is effected by connecting e.g. circuits which shunt the transistor stages, wherein, however, the mechanical couplings arranged in the signal path are unreliable and may cause interference. Using relays is undesirable since they are less reliable at high frequencies because of the mechanical parts they comprise and because fitting them into electronic solutions causes problems. Alternatively, amplification can be changed by connecting adjustable amplifiers to the circuit, but the problem with this type of transistor stage is a varying impedance level, which must be compensated for by arranging matching circuits on the input and output sides of the transistor stage.
The aim of the invention is, therefore, to achieve a simple and reliable circuit which can advantageously be used in a cable television network. This aim is achieved by means of the invention in such a way that the circuit's operating voltage is supplied through coupling elements, by means of which the polarity of the circuit's operating voltage can be changed if desired, in accordance with which the active element of the circuit operates either as an amplifier or as a voltage follower without the input or output poles changing .
According to the invention the input and output poles of the radio frequency or RF-signal do not change when the function of the active circuit is changed. The coupling elements only affect the direct current circuits and thus the elements do not interfere with the wide-band RF-signal.
The circuit relating to the invention has a simple and reliable structure, as a single transistor stage is advantageously used and can be controlled to be either an amplifier or a voltage follower. Thanks to this solution, no separate circuits shunting the amplifier or amplifiers connected in series are needed.
The invention is described in greater detail in the following by means of an example and with reference to the enclosed drawing in the figure of which is shown the connectable transistor stage relating to the invention.
The transistor stage Tl shown in the figure is used as a dual-purpose stage, on the one hand as a wide-band amplifier stage and on the other as a voltage follower. The function is selected on the coupling's simultaneously functioning keys SI - S4, by means of which the polarity of the circuit's operating voltage is changed. The couplings can be realized in other ways, too, known to a person skilled in the art, e.g. by means of semiconductor couplings. In both functions the factors affecting the quality of the RF-signal, such as the distortion properties and the noise performance as well as the impedance level remain essentially the same. In the voltage follower function the transducer loss is as small as possible.
In the amplifier function the keys SI - S4 of the coupling element are in position 1. In this case the NPN-transistor stage functions as an ordinary feedback common-emitter stage. The amplification is determined by the feedback elements LC and RC,.when the PIN-diode pair D1-D2 is made conductive by forward direct current +12 V on key S4. The circuit's capacitances and inductances have, in accordance with the practice in the field, an RF-signal path from input RF IN to output RF OUT, which is separated from the transistor's direct current circuits.
In the voltage follower function, when the coupling's keys are in position 2, the direction of the collector current of transistor Tl is reversed, that is, from emitter to collector. The value of the collector current is limited by means of the resistance 1.5 kohm, connected through key S3, to about 20mA. The PIN-diodes in the emitter circuit are then in a blocked state and no direct current flows through the circuit, and thus they create a sufficiently high impedance from the emitter to the ground. This voltage follower functions in a different way than the conventional solution, and thus in the present solution the collector current RF OUT follows the base voltage RF IN.
The other circuit elements shown in the figure of the example are not described more closely in this application as their functioning is known as such and obvious to one skilled in the art.
The circuit relating to the invention can advantageously be used in a cable television network. Tests carried out with the circuit have shown the circuit to function in accordance with the targets set for it.

Claims

1. A wide-band active RF-circuit, the amplification of which is controllable, characterized in that the circuit's operating voltage is supplied through coupling elements (SI - S4), whereupon the polarity of the circuit's operating voltage can be changed if desired, in accordance with which the circuit's active element (Tl) functions either as an amplifier or as a voltage follower without the input or output poles (RF IN, RF OUT) being changed.
2. A circuit as claimed in claim 1, characterized in that the active element (Tl) is a wide-band element.
3. A circuit as claimed in claim 1 or 2, characterized in that the active element (Tl) is a transistor.
4. A circuit as claimed in claim 3, charaterized in that as a voltage follower, the transistor's (Tl) collector current follows the base current.
5. A circuit as claimed in any of the claims 1 to 4, characterized in that the circuit's input and output impedance levels are the same in both functional states.
6. The use of a circuit as claimed in any of the above claims as an amplifier connected to a cable television network.
PCT/FI1991/000117 1990-04-25 1991-04-18 A wide-band active rf-circuit WO1991016761A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI902063A FI87029C (en) 1990-04-25 1990-04-25 Broadband active RF circuit
FI902063 1990-04-25

Publications (1)

Publication Number Publication Date
WO1991016761A1 true WO1991016761A1 (en) 1991-10-31

Family

ID=8530330

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1991/000117 WO1991016761A1 (en) 1990-04-25 1991-04-18 A wide-band active rf-circuit

Country Status (2)

Country Link
FI (1) FI87029C (en)
WO (1) WO1991016761A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241284A (en) * 1990-02-16 1993-08-31 Nokia Mobile Phones Ltd. Circuit arrangement for connecting RF amplifier and supply voltage filter
WO1993021703A1 (en) * 1992-04-15 1993-10-28 Coachline Video Express Pty Ltd Signal distribution system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0368528A2 (en) * 1988-11-09 1990-05-16 STMicroelectronics S.r.l. Audio amplifier with mute and stand-by states

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0368528A2 (en) * 1988-11-09 1990-05-16 STMicroelectronics S.r.l. Audio amplifier with mute and stand-by states

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 11, No. 341, E554; & JP,A,62 122 306, MITSUBISHI ELECTRIC CORP, 03-06-1987. *
PATENT ABSTRACTS OF JAPAN, Vol. 11, No. 376, E563; & JP,A,62 143 511, 26-06-1987, HITACHI LTD, see "purpose". *
PATENT ABSTRACTS OF JAPAN, Vol. 8, No. 277, E285; & JP,A,59 147 514, ROOMU K.K., 23-08-1984. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241284A (en) * 1990-02-16 1993-08-31 Nokia Mobile Phones Ltd. Circuit arrangement for connecting RF amplifier and supply voltage filter
WO1993021703A1 (en) * 1992-04-15 1993-10-28 Coachline Video Express Pty Ltd Signal distribution system

Also Published As

Publication number Publication date
FI87029C (en) 1992-11-10
FI902063A (en) 1991-10-26
FI87029B (en) 1992-07-31
FI902063A0 (en) 1990-04-25

Similar Documents

Publication Publication Date Title
JP4765036B2 (en) Variable gain amplifier with improved linearity
US6522195B2 (en) Low noise amplifier having bypass circuitry
US6351183B1 (en) Switched amplifying device
US6724259B2 (en) Variable gain amplifier
US7057457B2 (en) Low-noise amplifying circuit
EP0350323A2 (en) Transmission line switch
EP1719243A2 (en) Radio frequency low noise amplifier with automatic gain control
US5398004A (en) HBT direct-coupled low noise wideband microwave amplifier
GB2379567A (en) A controllable attenuator comprising a controllable shunting transistor and a controllable bypass transistor
US4205276A (en) Audio amplifier with low AM radiation
US5708391A (en) High frequency differential filter with CMOS control
US6919774B2 (en) Broadband PIN diode attenuator bias network
JPH1079646A (en) Switching enable band pass filter for multi-band tuner
WO2003090344A1 (en) Method and/or apparatus for controlling a common-base amplifier
US5339019A (en) Current sink
US5057791A (en) Device and method for bi-directional amplification with a JFET
KR100295678B1 (en) Linear gain control amplifier
US4170756A (en) Versatile transceiver coupling network
US3801922A (en) Rf amplifier control system
US7443243B2 (en) High frequency amplifier having an attenuator
KR20010075044A (en) A two-port with a frequency-dependent network
WO1991016761A1 (en) A wide-band active rf-circuit
KR100587450B1 (en) High frequency device
US4424462A (en) Switched delay circuit
US5705953A (en) Device bias based supplemental amplification

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA CH DE DK ES FI GB NL NO PL SE US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

NENP Non-entry into the national phase

Ref country code: CA