CA2014772A1 - Transmission link - Google Patents
Transmission linkInfo
- Publication number
- CA2014772A1 CA2014772A1 CA002014772A CA2014772A CA2014772A1 CA 2014772 A1 CA2014772 A1 CA 2014772A1 CA 002014772 A CA002014772 A CA 002014772A CA 2014772 A CA2014772 A CA 2014772A CA 2014772 A1 CA2014772 A1 CA 2014772A1
- Authority
- CA
- Canada
- Prior art keywords
- modulating
- frequency
- modulated
- pulses
- transmission link
- 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.)
- Abandoned
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 41
- 238000011156 evaluation Methods 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims description 17
- 238000010586 diagram Methods 0.000 description 4
- 230000036039 immunity Effects 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 230000001702 transmitter Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08C—TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS
- G08C23/00—Non-electrical signal transmission systems, e.g. optical systems
- G08C23/04—Non-electrical signal transmission systems, e.g. optical systems using light waves, e.g. infrared
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B14/00—Transmission systems not characterised by the medium used for transmission
- H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
- H04B14/023—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using pulse amplitude modulation
Abstract
ABSTRACT OF THE DISCLOSURE
A transmission link for transmitting a sequence of signals comprising pulse and interval signals, across a transmission medium from a transmitter to a receiver circuit of a receiver, whereby each pulse signal is modulated with a frequency. At least two frequencies are used to modulate the pulses, and a separate evaluation circuit is provided in the receiver for each modulating frequency. The output signals of the evaluation circuits are concatenated (linked in series) by a AND-gate circuit.
A transmission link for transmitting a sequence of signals comprising pulse and interval signals, across a transmission medium from a transmitter to a receiver circuit of a receiver, whereby each pulse signal is modulated with a frequency. At least two frequencies are used to modulate the pulses, and a separate evaluation circuit is provided in the receiver for each modulating frequency. The output signals of the evaluation circuits are concatenated (linked in series) by a AND-gate circuit.
Description
T~N~IS~IGN LINR
Backqround of the Invention This invention relates to a transmission link having high interference immunity and, more particularly, to a transmission link ~or transmitting a succession of pulses separated by intervals to a receiving circuit of a receiver, in which each pulse is modulated with a frequency.
In known types of transmission links, such as infrared transmission links, each pulse signal is usually modulated with one frequency. In a transmission link of this type, pulse signals have a frequency of approximately 1 to 10 kH~, and the modulating frequency in a known system called "Infra-fern", lies at approximately 40 kHz.
When disturbances appear in the pulse frequency or in the modulating frequency, the transmission link cannot always be kept free of disturbances despite the increased reliability through the use of a modulating frequency.
There is a need for a transmission link having a high interference immunity, low energy consumption, and " simple design.
Summary o__the I vention This and other needs are satisfied by the present invention in the first instance by using a .
transmissiOn link having at least two ~requencies for modulating the pulse siynals. A separate evaluation circuit ls provided in the receiver ~or each modulating frequency. The outputs of the evaluation circuits are each coupled to an AND gate. The signal appearing at the receiver circuit is only accepted when it is received without disturbance over each of the transmission links, each transmission link corresponding to a modulating frequency. The higher the number of transmission links, lo the more likely erroneous in~ormation will be excluded at the receiver.
The signal, which contains the message or information, can be a baseband or an encoded signal. The signal can be encoded ~y a variety of methods including dual phase, PPM, PAM etc.
In a further development of the present invention, the transmission link is constructed so that a first modulating frequenc~ which modulates the pulses is modulated by a second, higher modulating frequency. This principle can be continued accordingly with a third or higher modulating frequency. In th~ case of two modulating frequencies, the first modulating frequency preferably lies in the 30 to 50 kHz range and the second modulating frequency lies in the 400 to 500 kHz range .
A frequency of 455 kHz, which i5 held open in AM radio for intermediate frequencies, can be used in a technically favorable manner in order to avoid electrical shielding measures such as on an infrared input amplifier.
The transmission link can also be constructed so that after the pulse signals have been modulated with a first modulating frequency, these modulated pulse signals are then alternately modulated by a second modulating frequency and third modulating frequency~ Fourth and higher frequencies can be used in this manner. The .
, .
~, .
.
. ~ .
7~
interference immunity can be increased when the additional modulating frequency has only a relatively small frequency diff~ren~ial compared to the previous frequency.
The present invention can be realized using many signalling methods, in particular, the transmission link can operate with infrared signals.
Brie Description of_the Drawin~s Fig. 1 is a block diagram of a transmission link.
Fig. 2 shows a waveform comprising a sequence of pulses and intervals that represent a signal or a sequence of signals.
Fig. 3 shows a waveform comprising pulses that are modulated with a first modulating frequency according to the present invention.
Fig. 4 shows a waveform comprising a sequence of pulses that has been modulated with a first modulating frequency and then modulated with a second, higher modulating frequency according to the present invention.
Fig. 4a is a block diagram of a transmitter using two consecutive modulating frequencies constructed according to the present invention.
Fig. 5 shows a waveform comprising a sequence of pulses that has been modulated with a first modulating frequency and then each modulated pulse is alternately modulated with a second and a third modulatiny frequency according to the present invention. Figs. 3, 4, and 5 are not drawn to scale.
Fig. 5a is a block diagram of a transmi-tter using three modulating frequencies constructed according to the present invention.
, : ' ~,~3~ 7~
Fig. 6 is a block cllayram of a receiver comprising two evaluation circuits for two difPerent modulating frequencies coupled ~o an AND gate.
Detailed Description Referring to Fig. 1, a transmiasion link 1 comprising a transmitter 2 and a receiver 3 i5 shown. A
sequence of pulses 4 spaced by intervals 5 are transmitted in a medium such as infrared light to the receiver circuit of the recPiver 3.
Referring to Fig.2, a waveform comprising a sequence of pulses spaced by in~ervals is shown. The pulses and intervals signals can represent the high and low signals of a binary signal system. In this known system high and low signals represent the binary digits 1 and 0.
Referring to Fig. 3, a waveform of pulses generated using a known method of modulation is shown. In this method, each pulse signal of Fig. 2 is modulated with one frequency (e.g. fl). In the prior art, modulation stops here. With the present invention the wave~orm of Fig. 3 is further modulated, i.e., according to the present invention, several frequencies are used to modulate the pulses.
Referring to Fig. 4, a waveform of one full pulse and a part of a pulse generated using a method of the present invention is shown. In this embodiment, two frequencies, fl and f2, are used to modulate the pulse signals. The first modulating frequency fl, corresponding to fl in Fig. 3, can have a frequency magnitude in the 30 to 50 kHz range, and the second modulating frequency can have a frequency magnitude in the 400 to 500 kHz range.
, , . . , :
- ~ ' ' , ', ' ,,, , ' .
Referring to Fig. 4a, the transmitter 2 ~or implementing the aforementioned me~hod is shown. Pulses are modulated by a first modulator 41. The first modulator 41 is coupled to a second modulator 43. Pulses modulated by the first modula~or 41 are then modulated by the second modulator 43. The resulting modulated waveform is then transmitted by the IR ~ransmitter 45.
Referring to Fig. 5, a waveform of pulse signals generated using another method of the pres~nt invention is shown. In this method of transmission, the pulse signals are modulated using three modulating frequencies. In a first step, the pulse signals are modula~ed by a first modulating frequency to obtain a waveform such as that shown in Fig. 3. Then, pulse signals are alternately modulated with a second and third modulating fr~quencies~
Referring to Fig. 5a, a transmitter which alternately modulates pulses using secon and third frequencies to obtain the waveform of Fig. 5 is shown.
Pulses are modulated at a first frequency by a first modulator 51. The firs~ modulator 51 is coupled to a multiplexor (Mux) 53. The input waveform is also coupled to a flip-flop 52. Each pulse signal appearing at the input of the first modulator 51 causes the flip-flop 52 to alternate its output between a high and low state. This alternating output controls the output of the Mux 53. Mux 53 alternately sends modulated pulses from the first modulator 51 to a second modulator 55 having a second fequency and a third modulator 57 having a third frequency~ The second modulator 55 and the third modulator 57 are coupled to an IR transmitter 59. Every pulse modulated by the second modulator 55 and the third modulator 57 is transmitted by the IR transmitter 59.
`; ' .
.:
.
7~.., The methods mentioned above for modulatiny pulse signals can be used in conjunction with known methods for encoding messages such as dual phase, PPM, PAM, etc.
Referring to Fig. 6, a block diagram of the receiver 3 is shown. The receiver 3 comprises at least two evaluation circuits 6 and 7 and an AND-gate circuit 8.
The modulated pulses appear at the inputs of the evaluation circuits 6 and 7. The evaluation circuits 6 and 7 correspond to the two modulating frequenci~s fl and f2. Therefore, only pulse signals having a modulating frequency equal to fl or f2 will pass, respectively, through the evaluation circuits 6 and 7. The outputs of the evaluation circuits 6 and 7 are concatenated in an AND-gate circuit 8. Therefore, the evaluation circuits 6 and 7 block all noise components appearing in the transmission signal.
Infrared signals can be used as the medium for the transmission link when modulating frequencies have a magnitude of approximately 455 kHz.
` ,,, ` ~ ': ' ' '' ' ' :
. - . . . . .
. . , ~
.
: ' ,' :' ..
Backqround of the Invention This invention relates to a transmission link having high interference immunity and, more particularly, to a transmission link ~or transmitting a succession of pulses separated by intervals to a receiving circuit of a receiver, in which each pulse is modulated with a frequency.
In known types of transmission links, such as infrared transmission links, each pulse signal is usually modulated with one frequency. In a transmission link of this type, pulse signals have a frequency of approximately 1 to 10 kH~, and the modulating frequency in a known system called "Infra-fern", lies at approximately 40 kHz.
When disturbances appear in the pulse frequency or in the modulating frequency, the transmission link cannot always be kept free of disturbances despite the increased reliability through the use of a modulating frequency.
There is a need for a transmission link having a high interference immunity, low energy consumption, and " simple design.
Summary o__the I vention This and other needs are satisfied by the present invention in the first instance by using a .
transmissiOn link having at least two ~requencies for modulating the pulse siynals. A separate evaluation circuit ls provided in the receiver ~or each modulating frequency. The outputs of the evaluation circuits are each coupled to an AND gate. The signal appearing at the receiver circuit is only accepted when it is received without disturbance over each of the transmission links, each transmission link corresponding to a modulating frequency. The higher the number of transmission links, lo the more likely erroneous in~ormation will be excluded at the receiver.
The signal, which contains the message or information, can be a baseband or an encoded signal. The signal can be encoded ~y a variety of methods including dual phase, PPM, PAM etc.
In a further development of the present invention, the transmission link is constructed so that a first modulating frequenc~ which modulates the pulses is modulated by a second, higher modulating frequency. This principle can be continued accordingly with a third or higher modulating frequency. In th~ case of two modulating frequencies, the first modulating frequency preferably lies in the 30 to 50 kHz range and the second modulating frequency lies in the 400 to 500 kHz range .
A frequency of 455 kHz, which i5 held open in AM radio for intermediate frequencies, can be used in a technically favorable manner in order to avoid electrical shielding measures such as on an infrared input amplifier.
The transmission link can also be constructed so that after the pulse signals have been modulated with a first modulating frequency, these modulated pulse signals are then alternately modulated by a second modulating frequency and third modulating frequency~ Fourth and higher frequencies can be used in this manner. The .
, .
~, .
.
. ~ .
7~
interference immunity can be increased when the additional modulating frequency has only a relatively small frequency diff~ren~ial compared to the previous frequency.
The present invention can be realized using many signalling methods, in particular, the transmission link can operate with infrared signals.
Brie Description of_the Drawin~s Fig. 1 is a block diagram of a transmission link.
Fig. 2 shows a waveform comprising a sequence of pulses and intervals that represent a signal or a sequence of signals.
Fig. 3 shows a waveform comprising pulses that are modulated with a first modulating frequency according to the present invention.
Fig. 4 shows a waveform comprising a sequence of pulses that has been modulated with a first modulating frequency and then modulated with a second, higher modulating frequency according to the present invention.
Fig. 4a is a block diagram of a transmitter using two consecutive modulating frequencies constructed according to the present invention.
Fig. 5 shows a waveform comprising a sequence of pulses that has been modulated with a first modulating frequency and then each modulated pulse is alternately modulated with a second and a third modulatiny frequency according to the present invention. Figs. 3, 4, and 5 are not drawn to scale.
Fig. 5a is a block diagram of a transmi-tter using three modulating frequencies constructed according to the present invention.
, : ' ~,~3~ 7~
Fig. 6 is a block cllayram of a receiver comprising two evaluation circuits for two difPerent modulating frequencies coupled ~o an AND gate.
Detailed Description Referring to Fig. 1, a transmiasion link 1 comprising a transmitter 2 and a receiver 3 i5 shown. A
sequence of pulses 4 spaced by intervals 5 are transmitted in a medium such as infrared light to the receiver circuit of the recPiver 3.
Referring to Fig.2, a waveform comprising a sequence of pulses spaced by in~ervals is shown. The pulses and intervals signals can represent the high and low signals of a binary signal system. In this known system high and low signals represent the binary digits 1 and 0.
Referring to Fig. 3, a waveform of pulses generated using a known method of modulation is shown. In this method, each pulse signal of Fig. 2 is modulated with one frequency (e.g. fl). In the prior art, modulation stops here. With the present invention the wave~orm of Fig. 3 is further modulated, i.e., according to the present invention, several frequencies are used to modulate the pulses.
Referring to Fig. 4, a waveform of one full pulse and a part of a pulse generated using a method of the present invention is shown. In this embodiment, two frequencies, fl and f2, are used to modulate the pulse signals. The first modulating frequency fl, corresponding to fl in Fig. 3, can have a frequency magnitude in the 30 to 50 kHz range, and the second modulating frequency can have a frequency magnitude in the 400 to 500 kHz range.
, , . . , :
- ~ ' ' , ', ' ,,, , ' .
Referring to Fig. 4a, the transmitter 2 ~or implementing the aforementioned me~hod is shown. Pulses are modulated by a first modulator 41. The first modulator 41 is coupled to a second modulator 43. Pulses modulated by the first modula~or 41 are then modulated by the second modulator 43. The resulting modulated waveform is then transmitted by the IR ~ransmitter 45.
Referring to Fig. 5, a waveform of pulse signals generated using another method of the pres~nt invention is shown. In this method of transmission, the pulse signals are modulated using three modulating frequencies. In a first step, the pulse signals are modula~ed by a first modulating frequency to obtain a waveform such as that shown in Fig. 3. Then, pulse signals are alternately modulated with a second and third modulating fr~quencies~
Referring to Fig. 5a, a transmitter which alternately modulates pulses using secon and third frequencies to obtain the waveform of Fig. 5 is shown.
Pulses are modulated at a first frequency by a first modulator 51. The firs~ modulator 51 is coupled to a multiplexor (Mux) 53. The input waveform is also coupled to a flip-flop 52. Each pulse signal appearing at the input of the first modulator 51 causes the flip-flop 52 to alternate its output between a high and low state. This alternating output controls the output of the Mux 53. Mux 53 alternately sends modulated pulses from the first modulator 51 to a second modulator 55 having a second fequency and a third modulator 57 having a third frequency~ The second modulator 55 and the third modulator 57 are coupled to an IR transmitter 59. Every pulse modulated by the second modulator 55 and the third modulator 57 is transmitted by the IR transmitter 59.
`; ' .
.:
.
7~.., The methods mentioned above for modulatiny pulse signals can be used in conjunction with known methods for encoding messages such as dual phase, PPM, PAM, etc.
Referring to Fig. 6, a block diagram of the receiver 3 is shown. The receiver 3 comprises at least two evaluation circuits 6 and 7 and an AND-gate circuit 8.
The modulated pulses appear at the inputs of the evaluation circuits 6 and 7. The evaluation circuits 6 and 7 correspond to the two modulating frequenci~s fl and f2. Therefore, only pulse signals having a modulating frequency equal to fl or f2 will pass, respectively, through the evaluation circuits 6 and 7. The outputs of the evaluation circuits 6 and 7 are concatenated in an AND-gate circuit 8. Therefore, the evaluation circuits 6 and 7 block all noise components appearing in the transmission signal.
Infrared signals can be used as the medium for the transmission link when modulating frequencies have a magnitude of approximately 455 kHz.
` ,,, ` ~ ': ' ' '' ' ' :
. - . . . . .
. . , ~
.
: ' ,' :' ..
Claims (18)
1. A transmission link for transmitting a sequence of pulses and intervals over a transmission medium comprising:
a transmitter including means for modulating pulses with at least two frequencies to form modulated pulse signals containing said two frequencies;
a receiver having a separate evaluation circuit corresponding to each modulation frequency, each evaluation circuit having as an input said modulated pulses and providing a demodulated output; and an AND-gate circuit, having at least two inputs, each input being coupled to a respective output of one of said evaluation circuits, whereby said AND-gate circuit concatenates the demodulated pulse signals appearing at the outputs of said evaluation circuits.
a transmitter including means for modulating pulses with at least two frequencies to form modulated pulse signals containing said two frequencies;
a receiver having a separate evaluation circuit corresponding to each modulation frequency, each evaluation circuit having as an input said modulated pulses and providing a demodulated output; and an AND-gate circuit, having at least two inputs, each input being coupled to a respective output of one of said evaluation circuits, whereby said AND-gate circuit concatenates the demodulated pulse signals appearing at the outputs of said evaluation circuits.
2. The transmission link of claim 1, wherein said means for modulating include first means for modulating each pulse signal with a first modulating frequency and second means for modulating each pulse with a second modulating frequency having a higher frequency magnitude than said first modulating frequency.
3. The transmission link of claim 2, wherein said first modulating frequency has a frequency magnitude in a range from 30 to 50 kHz and the second modulating frequency has a frequency magnitude in a range from 400 to 500 kHz.
4. The transmission link of claim 1, wherein said means for modulating include first means for modulating each pulse signal with a first modulating frequency to form a modulated pulse signal, and second and third means to modulate each modulated pulse signal alternately with a second and third modulating frequency.
5. The transmission link of claim 4, wherein said modulating means includes means to modulate each modulated pulse signal alternately with three or more additional modulating frequencies.
6. The transmission link of claim 1, wherein said transmission medium is infrared light.
7. The transmission link of claim 2, wherein said transmission medium is infrared light.
8. The transmission link of claim 3, wherein said transmission medium is infrared light.
9. The transmission link of claim 4, wherein said transmission medium is infrared light.
10. A method of transmitting a sequence of pulses and intervals over a transmission medium comprising:
modulating pulses with at least two frequencies to form modulated pulses containing said two frequencies;
transmitting said modulated pulses over the medium;
seperately receiving said modulated pulses;
evaluating said pulses at each modulating frequency; and ANDing the respective results of said evaluations whereby said evaluation results will be concatenated.
modulating pulses with at least two frequencies to form modulated pulses containing said two frequencies;
transmitting said modulated pulses over the medium;
seperately receiving said modulated pulses;
evaluating said pulses at each modulating frequency; and ANDing the respective results of said evaluations whereby said evaluation results will be concatenated.
11. The method of claim 10, comprising modulating each pulse signal with a first modulating frequency and a second modulating frequency having a higher frequency magnitude than the first modulating frequency.
12. The method of claim 11, wherein said first modulating frequency has a frequency magnitude in a range from 30 to 50 kHz and the second modulating frequency has a frequency magnitude in a range from 400 to 500 kHz.
13. The method of claim 10, comprising modulating each pulse signal with a first modulating frequency to form a modulated pulse signal, and further modulating each modulated pulse signal alternately with a second and third modulating frequency.
14. The method of claim 13, comprising modulating each modulated pulse signal alternately with three or more additional modulating frequencies.
15. The method of claim 10, wherein said transmission medium is infrared light.
16. The method of claim 11, wherein said transmission medium is infrared light.
17. The method of claim 12, wherein said transmission medium is infrared light.
18. The transmission link of claim 13, wherein said transmission medium is infrared light.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP89107170 | 1989-04-20 | ||
| EP89107170.6 | 1989-04-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2014772A1 true CA2014772A1 (en) | 1990-10-20 |
Family
ID=8201264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002014772A Abandoned CA2014772A1 (en) | 1989-04-20 | 1990-04-18 | Transmission link |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5020154A (en) |
| EP (1) | EP0393470B1 (en) |
| AT (1) | ATE118938T1 (en) |
| CA (1) | CA2014772A1 (en) |
| DE (1) | DE59008497D1 (en) |
| DK (1) | DK0393470T3 (en) |
| ES (1) | ES2068272T3 (en) |
| PT (1) | PT93801B (en) |
Families Citing this family (31)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3027275B2 (en) * | 1991-12-23 | 2000-03-27 | ゼネラル・エレクトリック・カンパニイ | Device to position cursor on monitor screen |
| DE4210069A1 (en) * | 1992-03-27 | 1993-09-30 | Asea Brown Boveri | Amplitude-modulated radio transmitter for various types of modulation, especially DSB, SSB and ISB |
| US5319797A (en) * | 1992-09-17 | 1994-06-07 | Rockwell International Corporation | Remote vehicle access featuring high security |
| US5663824A (en) * | 1993-11-02 | 1997-09-02 | Lucent Technologies Inc. | Optical modulators as monolithically integrated optical isolators |
| HUP9702398A3 (en) * | 1995-03-30 | 1998-06-29 | Siemens Ag | Method of generating a.c. information for a bus system, and transmission unit for carrying out the method |
| US6061551A (en) | 1998-10-21 | 2000-05-09 | Parkervision, Inc. | Method and system for down-converting electromagnetic signals |
| US6091940A (en) | 1998-10-21 | 2000-07-18 | Parkervision, Inc. | Method and system for frequency up-conversion |
| US6694128B1 (en) | 1998-08-18 | 2004-02-17 | Parkervision, Inc. | Frequency synthesizer using universal frequency translation technology |
| US7515896B1 (en) | 1998-10-21 | 2009-04-07 | Parkervision, Inc. | Method and system for down-converting an electromagnetic signal, and transforms for same, and aperture relationships |
| US6049706A (en) | 1998-10-21 | 2000-04-11 | Parkervision, Inc. | Integrated frequency translation and selectivity |
| US6542722B1 (en) | 1998-10-21 | 2003-04-01 | Parkervision, Inc. | Method and system for frequency up-conversion with variety of transmitter configurations |
| US6560301B1 (en) | 1998-10-21 | 2003-05-06 | Parkervision, Inc. | Integrated frequency translation and selectivity with a variety of filter embodiments |
| US7039372B1 (en) | 1998-10-21 | 2006-05-02 | Parkervision, Inc. | Method and system for frequency up-conversion with modulation embodiments |
| US6061555A (en) | 1998-10-21 | 2000-05-09 | Parkervision, Inc. | Method and system for ensuring reception of a communications signal |
| US7236754B2 (en) | 1999-08-23 | 2007-06-26 | Parkervision, Inc. | Method and system for frequency up-conversion |
| US6813485B2 (en) | 1998-10-21 | 2004-11-02 | Parkervision, Inc. | Method and system for down-converting and up-converting an electromagnetic signal, and transforms for same |
| US6370371B1 (en) | 1998-10-21 | 2002-04-09 | Parkervision, Inc. | Applications of universal frequency translation |
| US6704549B1 (en) | 1999-03-03 | 2004-03-09 | Parkvision, Inc. | Multi-mode, multi-band communication system |
| US6704558B1 (en) | 1999-01-22 | 2004-03-09 | Parkervision, Inc. | Image-reject down-converter and embodiments thereof, such as the family radio service |
| US6879817B1 (en) | 1999-04-16 | 2005-04-12 | Parkervision, Inc. | DC offset, re-radiation, and I/Q solutions using universal frequency translation technology |
| US6853690B1 (en) | 1999-04-16 | 2005-02-08 | Parkervision, Inc. | Method, system and apparatus for balanced frequency up-conversion of a baseband signal and 4-phase receiver and transceiver embodiments |
| US7110444B1 (en) | 1999-08-04 | 2006-09-19 | Parkervision, Inc. | Wireless local area network (WLAN) using universal frequency translation technology including multi-phase embodiments and circuit implementations |
| US7065162B1 (en) | 1999-04-16 | 2006-06-20 | Parkervision, Inc. | Method and system for down-converting an electromagnetic signal, and transforms for same |
| US7693230B2 (en) | 1999-04-16 | 2010-04-06 | Parkervision, Inc. | Apparatus and method of differential IQ frequency up-conversion |
| US8295406B1 (en) | 1999-08-04 | 2012-10-23 | Parkervision, Inc. | Universal platform module for a plurality of communication protocols |
| US7010286B2 (en) | 2000-04-14 | 2006-03-07 | Parkervision, Inc. | Apparatus, system, and method for down-converting and up-converting electromagnetic signals |
| US7454453B2 (en) | 2000-11-14 | 2008-11-18 | Parkervision, Inc. | Methods, systems, and computer program products for parallel correlation and applications thereof |
| US7072427B2 (en) | 2001-11-09 | 2006-07-04 | Parkervision, Inc. | Method and apparatus for reducing DC offsets in a communication system |
| US7460584B2 (en) | 2002-07-18 | 2008-12-02 | Parkervision, Inc. | Networking methods and systems |
| US7379883B2 (en) | 2002-07-18 | 2008-05-27 | Parkervision, Inc. | Networking methods and systems |
| DE10304081B4 (en) * | 2002-10-24 | 2007-09-13 | Visteon Global Technologies Inc., Van Buren | Access system for a motor vehicle |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2952812A (en) * | 1956-01-27 | 1960-09-13 | California Research Corp | Pulse modulation function multiplier |
| US3956626A (en) * | 1973-06-14 | 1976-05-11 | Mcdonnell Douglas Corporation | Pulse quaternary communication means |
| US4150284A (en) * | 1977-04-28 | 1979-04-17 | Texas Instruments Incorporated | Medical patient condition monitoring system |
| DE2719937A1 (en) * | 1977-05-04 | 1978-11-09 | Bosch Gmbh Robert | Optically coupled signal transmission - has antenna received signal transmitted over optically isolated coupling |
| AT358959B (en) * | 1977-11-21 | 1980-10-10 | Kibolac Handelsgesellschaft M | REMOTE CONTROL SWITCH |
| CA1187187A (en) * | 1981-04-27 | 1985-05-14 | Akira Fukuda | Method and system for pulse communication |
| DE3337205A1 (en) * | 1983-10-13 | 1985-04-25 | Telefunken Fernseh Und Rundfunk Gmbh, 3000 Hannover | Infrared remote control system for an electric appliance, in particular a TV receiver |
| JPS60263590A (en) * | 1984-06-11 | 1985-12-27 | Sumitomo Electric Ind Ltd | Picture signal transmitting system |
| JPS61198935A (en) * | 1985-02-28 | 1986-09-03 | Toshiba Corp | Optical transmission system |
-
1990
- 1990-04-09 ES ES90106801T patent/ES2068272T3/en not_active Expired - Lifetime
- 1990-04-09 DK DK90106801.5T patent/DK0393470T3/en active
- 1990-04-09 AT AT90106801T patent/ATE118938T1/en not_active IP Right Cessation
- 1990-04-09 EP EP90106801A patent/EP0393470B1/en not_active Expired - Lifetime
- 1990-04-09 DE DE59008497T patent/DE59008497D1/en not_active Expired - Fee Related
- 1990-04-18 CA CA002014772A patent/CA2014772A1/en not_active Abandoned
- 1990-04-19 US US07/511,196 patent/US5020154A/en not_active Expired - Fee Related
- 1990-04-19 PT PT93801A patent/PT93801B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| PT93801A (en) | 1990-11-20 |
| US5020154A (en) | 1991-05-28 |
| PT93801B (en) | 1998-05-29 |
| EP0393470B1 (en) | 1995-02-22 |
| DK0393470T3 (en) | 1995-07-10 |
| ATE118938T1 (en) | 1995-03-15 |
| DE59008497D1 (en) | 1995-03-30 |
| EP0393470A1 (en) | 1990-10-24 |
| ES2068272T3 (en) | 1995-04-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |