CA2160259A1 - Television signal amplification device, with variable operating class which is predetermined in order to eliminate transmission errors - Google Patents
Television signal amplification device, with variable operating class which is predetermined in order to eliminate transmission errorsInfo
- Publication number
- CA2160259A1 CA2160259A1 CA002160259A CA2160259A CA2160259A1 CA 2160259 A1 CA2160259 A1 CA 2160259A1 CA 002160259 A CA002160259 A CA 002160259A CA 2160259 A CA2160259 A CA 2160259A CA 2160259 A1 CA2160259 A1 CA 2160259A1
- Authority
- CA
- Canada
- Prior art keywords
- amplifier
- circuit
- digital
- bias point
- television signal
- 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
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
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
- H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
- H03F1/3247—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits using feedback acting on predistortion circuits
-
- 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
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
- H03F1/0205—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
- H03F1/0261—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers with control of the polarisation voltage or current, e.g. gliding Class A
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Amplifiers (AREA)
- Transmitters (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
Television signal amplification device, with variable operating class which is predetermined in order to eliminate transmission errors The device comprises an amplifier (1) coupled to a circuit (2) for control of the shifting of the bias point of the amplifier depending on the standard of the television signals applied to the input of the amplifier.
Applications relate to the production of multi-standard television transmitters.
Applications relate to the production of multi-standard television transmitters.
Description
Television signal amplification device, with variable operating class which is predetermined in order to eliminate transmission errors The present invention relates to a television signal amplification device with variable operating class which is predetermined in order to eliminate transmission errors.
It applies particularly to producing television transmitters which have to transmit signals to very different standards: current analogue standards and future digital standards.
In the current embodiments of television trans-mitters two types of amplification are u6ed, in general. A first type concerns amplification known as "separate" amplification, consisting of two or three channels, one for the image and one or two channels for transmitting the sound. A second type concerns ampli-fication known as "common" amplification, which con-sists of a single channel for transmitting the image and the sound. For this second type of amplification the constraints relating to retransmission of the sig-nal are generally strict, since it is important that the di~tortion of the signal caused by the non-linearities of the amplification device are very low, so that transmission of the television signal is not affected by noise within the image and by trans-modulations of the image signal onto the sound channels and conversely. However, whatever these two types of amplification, it is important that the television transmitter thus produced be transparent for the tele-vision standard to be transmitted. In fact, whatever the standard, PAL, SECAM, NTSC, it is very important that the output signal should be a faithful reflection of the signal which is applied to the input of the amplification devices of the transmitter, and the latter devices must therefore not contribute disturbances such ~ as compression due to non-linearities.
- la -In the case of the common amplification, it is generally preferred to bias the power amplifier into class A 80 as to m;n;m; ze the low-level inter-modulation~, since, in this case, the devices for correction by predistortion are fairly simple to produce and con~ist simply in carrying out a high-level expansion since the low levels are transmitted faith-fully. However, the well-known disadvantage of this 2~60259 amplification class is that it exhibits a low power efficiency, of the order of 20 to 25% at mo6t, which leads to prohibitive consumption of electric current for very high-power transmitters.
~ ecent studie6 have shown, however, that it was po6sible to precorrect amplification systems of AB
class by a double correction of the low levels and of the high levels, applicable also to the type of common amplification by a single amplification stage. However, this is clearly not suitable when, to optimize the efficiency of the amplification channel, it is necessary to place two or three stages in class AB in series. In this case the level of intermodulation of the television signal is then of the order of 40 dB, which is a prohibitive level in the presence of images and of 60unds, and the cumulated distortion levels of the three stages consisting of three low-level distortions and of three high-level distortions become too great to be corrected to the level of 62 dB which is necessary for transmission of the sound pair. These considerations dictate the use of separate ampli-fication in order to avoid the limitations stem~;ng from these phenomena, accepting an intermodulation of 40 dB, a level which is sufficient for an image channel alone and which can easily be obtained with correct stability.
However, for transmitting television signals within the new digital standards of high-definition television (HDTV), it emerges that, the more sophi6ti-cated the coding of the channel the more it requires a constant transfer characteristic during power amplification, which dictates the use of effective lineari-zation techniques. Whereas a class B/BC bias mode may be suitable and efficient for a QPSK digital modulation type, for example, this type of bias is no longer suitable for 16QAM - PAL/NTSC or PAL/NTSC-type modu-lation, and still les6 for 64QAM modulation types, which make it necessary to use amplifiers biased in class A for the type of ultra-linear operation in - 2a -common amplification mode.
Hence it is not currently possible, with a single tran6mitter, to be able to satisfy all the television signal transmission services, within the various standards.
The object of the invention is to mitigate the abovementioned drawbacks.
To this end, the subject of the invention is a television signal amplification device with variable class of operation which is predetermined 2~ 6~259 in order to eliminate digital television signals transmission errors, charac-terized in that it comprises an amplifier coupled to a circuit for control of the shifting of the bias point of the amplifier, depending on the standard of the television signals applied to the input of the amplifier on the mean power supply current of the amplifier and on the out-of-band noise.
The main advantage of the invention is that it makes it possible to produce television transmitters which are compatible and optimized for the current television st~n~rds and for the future st~n~rds. It also makes it po~sible to optimize the performance of these transmitters dep~n~;ng on each type of modulation by promoting, in particular, the performance of current st~nA~rds by optimizing the efficiency of the ampli-fication system within each of the st~n~rds of use. In digital transmission, it makes it po~sible to optimize the bit error rate (BER) for predetermination of the class of operation, to m;n;m;ze the bit error rate (BER) at the amplification output and input by virtue of a feedback loop for slaving to this error rate.
Other characteristics and advantages of the invention will emerge in the description which follows given with regard to the figures of the attached drawings which represent:
- Figure 1, a television signal amplifier with class of operation which is variable dep~n~;ng on the standard of the television signals to be transmitted, according to the invention.
- Figure 2, a table indicating the operating points of a transmitter operating within the 4PSK, 16QAM and 64QAM 8 tandards.
- Figure 3, a second embodiment of the amplifier of Figure 1 equipped with a device for optimizing the bit error rate by automatic choice of the class of operation.
- Figure 4,l a third embodiment of the ampli-AMENDED PAGE
- 3a -fication device according to Figure 1 equipped with a device for optimizing the bit error rates by automatic choice of the class of operation and of the level of precorrection of the television signal.
- Figures 5 to 8, tables representing biasing classes of transmitters using an amplification device in accordance with the invention.
- Figure 9, a transmission spectrum in 64QAM
digital standard.
- Figure 10, an embodiment of the circuit for control of the bias point represented in Figures 1, 3 and 4.
AMENDED PAGE
216~259 - Figure 11, a process for control of the shifting of the bias point of the amplifier of Figures 1, 3 and 4 in the form of a flowchart.
The amplification device according to the invention which is represented in Figure 1 makes it possible to optimize the amplification class of the amplifiers of television transmitters depending on the nature of the television signal to be transmitted. To this end, the amplification device represented in Figure 1 includes a high-frequency signal amplifier 1 coupled to a circuit 2 for control of the shifting of the bias point of the amplifier 1. A circuit 2 supplies a signal Vp for control of the bias of the output stage of the amplifier 1 as a function of the mean current consumed by the amplifier 1 which is itself a function of the standard of transmission of the television signal, by slaving the mean current consumed by the amplifier 1 correspon~ng to the st~n~rd, using any known device, which is not represented. The measurement of this mean current is performed by the circuit 2 which makes use of the voltage developed at the terminals of a resistor 3 placed in series between a power supply terminal for the amplifier 1 and an external power supply generator, not represented, supplying a voltage Vc. In this embodiment, the shift control circuit 2 predefines the various classes of operation of the amplifier 1 on the basis of the standard6 to be transmitted. It allows transmissions with multiple amplitude states, for example, as Figure 2 shows, by placing the amplifier 1 in the class A
operating mode and by setting the mean output power to a low level in order to take account of the low efficiency of the output amplification stage of the amplifier. For transmissions including only a few amplitude states it makes it possible to bias the amplifier 1 into class AB, enabling a higher mean out-put power. Finally, for constant-amplitude operating modes, -the circuit ~2 makes it possible to bias the amplifier 1 into class BC, for example, in this way enabling an operating mode with high mean power.
In the embodiment of Figure 3 in which the elements corresponding to tho6e of Figure 1 are represented with the same references, the circuit of Figure 1 is completed by a circuit for measuring the error rate in the digital information transmitted by the amplifier 1 when this amplifier is used for trans-mitting digital television signals. This measurement circuit 4 acts directly on the circuit for controlling the shifting of the bias point of the amplifier 2.
Finally, the amplification circuit of the Figure 3 is effectively completed in Figure 4 by a pre-correction circuit 5 controlled by the bias point 6hift control circuit 2.
According to the embodiment of the bias point shift control circuit 2 which is represented in Figure 10, the circuit includes a microprocessor 6, a set of programmable read-only memories 7, a random-access memory 8, an analogue-digital conversion circuit 9 and a digital-analogue conversion circuit 10 which are coupled together by means of a single bus 11. The programmable read-only memories 7 contain a table for each type of modulation. The values of the power supply current of the amplifier 3 are applied to the input of the analogue-digital converter 3 80 as to be quantized before being used by the microprocessor 6 to calculate values of mean and m~; mllm power supplied by the ampli-fier 3. The circuit 2 also includes a device 12 for detecting synchronization signals, the number of levels of the modulation and the bit error rate.
The microprocessor 6 is program~ed as repre-sented in Figure 11 in order to identify the configuration of the amplifier depending on the data which it receives from the analogue-digital converter 9 and from the detection device 12 and, on the basis of the measurements performed, to apply the values for correction of the bias point of the amplifier 3 via the digital-analogue converter 10. The process commences at step 13 with identification of the configuration of the amplifier 3, followed, at step 14, by loading into the random-access memory 8 of the tables read in the memory 7 corresponding to the configuration identified.
The bias values for the amplifier are applied at step 15. At steps 16, 17 and 18 the device checks itself, by measuring the characteristics of the ampli-fier 3 at step 16 and by applying correction values to the amplifier 3, at step 18, if the characteristics of the amplifier 3 at step 17 do not correspond to those expected.
Signal/noise ratios at a given bit error rate (BER) for 4PSK, 16QAM and 64QAM modulations obtained by amplifiers operating according to the principle of Figures 1, 3 and 4 are set out in the table of Figure 5.
Comparison of the range characteristics of a transmitter operating in 800-watt class AB in conven-tional television and in digital television operating in OFDM modulation incorporating amplification accor-ding to the invention is shown by the table of Figure 6. In the three cases of OFDM modulation of Figure 6 (64QAM, 16QAM and 4PSK), the determination of the out-put power usable is done by ~yA~i n; ng the curves of bit error rate as a function of output power of the ampli-fier with constant signal-to-noise ratio, tolerating, for example, a degradation of the bit error rate due to the saturation non-linearity of the amplifier. In this latter case the results obtained are shown in the table of Figure 7. A margin of 1 dB, 80 as to attenuate the non-linearities due to the contribution of white noise has been included.
The table of Figure 8 shows the implementation margin to be taken into account for a class AB trans-mitter amplifier operating in OFDM modulation. It is apparent that the implementation margin to be taken into account decreasès when the number of points of the OFDM constellation increases.
Figure 9 shows the effect of the automatic correction on the HF spectrum of the ~ignal transmitted in 64QAM digital st~n~d. Measurement of the error rate can thus advantageously be replaced by a circuit for measuring the out-of-band intermodulation noise which replaces the circuit 4 of Figures 3 and 4.
The curve A repre~ents the spectrum before correction. The curve B reprecents the m;nim; zed spectrum after correction and thus corresponds to optimization of the transmission error rate by automatic means.
It applies particularly to producing television transmitters which have to transmit signals to very different standards: current analogue standards and future digital standards.
In the current embodiments of television trans-mitters two types of amplification are u6ed, in general. A first type concerns amplification known as "separate" amplification, consisting of two or three channels, one for the image and one or two channels for transmitting the sound. A second type concerns ampli-fication known as "common" amplification, which con-sists of a single channel for transmitting the image and the sound. For this second type of amplification the constraints relating to retransmission of the sig-nal are generally strict, since it is important that the di~tortion of the signal caused by the non-linearities of the amplification device are very low, so that transmission of the television signal is not affected by noise within the image and by trans-modulations of the image signal onto the sound channels and conversely. However, whatever these two types of amplification, it is important that the television transmitter thus produced be transparent for the tele-vision standard to be transmitted. In fact, whatever the standard, PAL, SECAM, NTSC, it is very important that the output signal should be a faithful reflection of the signal which is applied to the input of the amplification devices of the transmitter, and the latter devices must therefore not contribute disturbances such ~ as compression due to non-linearities.
- la -In the case of the common amplification, it is generally preferred to bias the power amplifier into class A 80 as to m;n;m; ze the low-level inter-modulation~, since, in this case, the devices for correction by predistortion are fairly simple to produce and con~ist simply in carrying out a high-level expansion since the low levels are transmitted faith-fully. However, the well-known disadvantage of this 2~60259 amplification class is that it exhibits a low power efficiency, of the order of 20 to 25% at mo6t, which leads to prohibitive consumption of electric current for very high-power transmitters.
~ ecent studie6 have shown, however, that it was po6sible to precorrect amplification systems of AB
class by a double correction of the low levels and of the high levels, applicable also to the type of common amplification by a single amplification stage. However, this is clearly not suitable when, to optimize the efficiency of the amplification channel, it is necessary to place two or three stages in class AB in series. In this case the level of intermodulation of the television signal is then of the order of 40 dB, which is a prohibitive level in the presence of images and of 60unds, and the cumulated distortion levels of the three stages consisting of three low-level distortions and of three high-level distortions become too great to be corrected to the level of 62 dB which is necessary for transmission of the sound pair. These considerations dictate the use of separate ampli-fication in order to avoid the limitations stem~;ng from these phenomena, accepting an intermodulation of 40 dB, a level which is sufficient for an image channel alone and which can easily be obtained with correct stability.
However, for transmitting television signals within the new digital standards of high-definition television (HDTV), it emerges that, the more sophi6ti-cated the coding of the channel the more it requires a constant transfer characteristic during power amplification, which dictates the use of effective lineari-zation techniques. Whereas a class B/BC bias mode may be suitable and efficient for a QPSK digital modulation type, for example, this type of bias is no longer suitable for 16QAM - PAL/NTSC or PAL/NTSC-type modu-lation, and still les6 for 64QAM modulation types, which make it necessary to use amplifiers biased in class A for the type of ultra-linear operation in - 2a -common amplification mode.
Hence it is not currently possible, with a single tran6mitter, to be able to satisfy all the television signal transmission services, within the various standards.
The object of the invention is to mitigate the abovementioned drawbacks.
To this end, the subject of the invention is a television signal amplification device with variable class of operation which is predetermined 2~ 6~259 in order to eliminate digital television signals transmission errors, charac-terized in that it comprises an amplifier coupled to a circuit for control of the shifting of the bias point of the amplifier, depending on the standard of the television signals applied to the input of the amplifier on the mean power supply current of the amplifier and on the out-of-band noise.
The main advantage of the invention is that it makes it possible to produce television transmitters which are compatible and optimized for the current television st~n~rds and for the future st~n~rds. It also makes it po~sible to optimize the performance of these transmitters dep~n~;ng on each type of modulation by promoting, in particular, the performance of current st~nA~rds by optimizing the efficiency of the ampli-fication system within each of the st~n~rds of use. In digital transmission, it makes it po~sible to optimize the bit error rate (BER) for predetermination of the class of operation, to m;n;m;ze the bit error rate (BER) at the amplification output and input by virtue of a feedback loop for slaving to this error rate.
Other characteristics and advantages of the invention will emerge in the description which follows given with regard to the figures of the attached drawings which represent:
- Figure 1, a television signal amplifier with class of operation which is variable dep~n~;ng on the standard of the television signals to be transmitted, according to the invention.
- Figure 2, a table indicating the operating points of a transmitter operating within the 4PSK, 16QAM and 64QAM 8 tandards.
- Figure 3, a second embodiment of the amplifier of Figure 1 equipped with a device for optimizing the bit error rate by automatic choice of the class of operation.
- Figure 4,l a third embodiment of the ampli-AMENDED PAGE
- 3a -fication device according to Figure 1 equipped with a device for optimizing the bit error rates by automatic choice of the class of operation and of the level of precorrection of the television signal.
- Figures 5 to 8, tables representing biasing classes of transmitters using an amplification device in accordance with the invention.
- Figure 9, a transmission spectrum in 64QAM
digital standard.
- Figure 10, an embodiment of the circuit for control of the bias point represented in Figures 1, 3 and 4.
AMENDED PAGE
216~259 - Figure 11, a process for control of the shifting of the bias point of the amplifier of Figures 1, 3 and 4 in the form of a flowchart.
The amplification device according to the invention which is represented in Figure 1 makes it possible to optimize the amplification class of the amplifiers of television transmitters depending on the nature of the television signal to be transmitted. To this end, the amplification device represented in Figure 1 includes a high-frequency signal amplifier 1 coupled to a circuit 2 for control of the shifting of the bias point of the amplifier 1. A circuit 2 supplies a signal Vp for control of the bias of the output stage of the amplifier 1 as a function of the mean current consumed by the amplifier 1 which is itself a function of the standard of transmission of the television signal, by slaving the mean current consumed by the amplifier 1 correspon~ng to the st~n~rd, using any known device, which is not represented. The measurement of this mean current is performed by the circuit 2 which makes use of the voltage developed at the terminals of a resistor 3 placed in series between a power supply terminal for the amplifier 1 and an external power supply generator, not represented, supplying a voltage Vc. In this embodiment, the shift control circuit 2 predefines the various classes of operation of the amplifier 1 on the basis of the standard6 to be transmitted. It allows transmissions with multiple amplitude states, for example, as Figure 2 shows, by placing the amplifier 1 in the class A
operating mode and by setting the mean output power to a low level in order to take account of the low efficiency of the output amplification stage of the amplifier. For transmissions including only a few amplitude states it makes it possible to bias the amplifier 1 into class AB, enabling a higher mean out-put power. Finally, for constant-amplitude operating modes, -the circuit ~2 makes it possible to bias the amplifier 1 into class BC, for example, in this way enabling an operating mode with high mean power.
In the embodiment of Figure 3 in which the elements corresponding to tho6e of Figure 1 are represented with the same references, the circuit of Figure 1 is completed by a circuit for measuring the error rate in the digital information transmitted by the amplifier 1 when this amplifier is used for trans-mitting digital television signals. This measurement circuit 4 acts directly on the circuit for controlling the shifting of the bias point of the amplifier 2.
Finally, the amplification circuit of the Figure 3 is effectively completed in Figure 4 by a pre-correction circuit 5 controlled by the bias point 6hift control circuit 2.
According to the embodiment of the bias point shift control circuit 2 which is represented in Figure 10, the circuit includes a microprocessor 6, a set of programmable read-only memories 7, a random-access memory 8, an analogue-digital conversion circuit 9 and a digital-analogue conversion circuit 10 which are coupled together by means of a single bus 11. The programmable read-only memories 7 contain a table for each type of modulation. The values of the power supply current of the amplifier 3 are applied to the input of the analogue-digital converter 3 80 as to be quantized before being used by the microprocessor 6 to calculate values of mean and m~; mllm power supplied by the ampli-fier 3. The circuit 2 also includes a device 12 for detecting synchronization signals, the number of levels of the modulation and the bit error rate.
The microprocessor 6 is program~ed as repre-sented in Figure 11 in order to identify the configuration of the amplifier depending on the data which it receives from the analogue-digital converter 9 and from the detection device 12 and, on the basis of the measurements performed, to apply the values for correction of the bias point of the amplifier 3 via the digital-analogue converter 10. The process commences at step 13 with identification of the configuration of the amplifier 3, followed, at step 14, by loading into the random-access memory 8 of the tables read in the memory 7 corresponding to the configuration identified.
The bias values for the amplifier are applied at step 15. At steps 16, 17 and 18 the device checks itself, by measuring the characteristics of the ampli-fier 3 at step 16 and by applying correction values to the amplifier 3, at step 18, if the characteristics of the amplifier 3 at step 17 do not correspond to those expected.
Signal/noise ratios at a given bit error rate (BER) for 4PSK, 16QAM and 64QAM modulations obtained by amplifiers operating according to the principle of Figures 1, 3 and 4 are set out in the table of Figure 5.
Comparison of the range characteristics of a transmitter operating in 800-watt class AB in conven-tional television and in digital television operating in OFDM modulation incorporating amplification accor-ding to the invention is shown by the table of Figure 6. In the three cases of OFDM modulation of Figure 6 (64QAM, 16QAM and 4PSK), the determination of the out-put power usable is done by ~yA~i n; ng the curves of bit error rate as a function of output power of the ampli-fier with constant signal-to-noise ratio, tolerating, for example, a degradation of the bit error rate due to the saturation non-linearity of the amplifier. In this latter case the results obtained are shown in the table of Figure 7. A margin of 1 dB, 80 as to attenuate the non-linearities due to the contribution of white noise has been included.
The table of Figure 8 shows the implementation margin to be taken into account for a class AB trans-mitter amplifier operating in OFDM modulation. It is apparent that the implementation margin to be taken into account decreasès when the number of points of the OFDM constellation increases.
Figure 9 shows the effect of the automatic correction on the HF spectrum of the ~ignal transmitted in 64QAM digital st~n~d. Measurement of the error rate can thus advantageously be replaced by a circuit for measuring the out-of-band intermodulation noise which replaces the circuit 4 of Figures 3 and 4.
The curve A repre~ents the spectrum before correction. The curve B reprecents the m;nim; zed spectrum after correction and thus corresponds to optimization of the transmission error rate by automatic means.
Claims (6)
1. Television signal amplification device with variable class of operation which is predetermined in order to eliminate digital television signal trans-mission errors, characterized in that it comprises an amplifier (1) coupled to a circuit (2) for control of the shifting of the bias point of the amplifier depending on the standard of the television signals applied to the input of the amplifier, on the mean power supply current of the amplifier (1) and on the out-of-band noise.
2. Device according to Claim 1, characterized in that it comprises a circuit (4) for measuring the error rate in the digital television signals transmitted by the amplifier, for shifting the bias point as a function of the error rate.
3. Device according to either of Claims 1 and 2, characterized in that it comprises a circuit (4) for measuring the out-of-band noise of the transmitted television signals for shifting the bias point.
4. Device according to any one of Claims 1 to 3, characterized in that it comprises a device (5) for precorrection of the television signal applied to the input of the amplifier (1) controlled by the bias point shift control circuit (2).
5. Device according to any one of Claims 1 to 4, characterized in that the control circuit (2) comprises a microprocessor (6) coupled via a bus (11) to a set of programmable read-only memories (7), a random-access memory (8) an analogue-digital conversion circuit (9), a digital-analogue conversion circuit (10) and to a device (12) for detecting synchronization signals, the number of levels of the modulation and the bit error rate, and in that the microprocessor (6) is programmed to identify the configuration of the amplifier (1) on the basis of data which it receives from the analogue-digital converter (9) and from the detection device (12) in order, on the basis of the measurements - 8a -performed, to apply the values for correcting the bias point of the amplifier (1) via the digital-analogue converter (10).
6. Device according to Claim 5, characterized in that, in the set of programmable read-only memories (7) are stored tables for adjusting the bias point depending on each type of modulation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR93/04312 | 1993-04-13 | ||
| FR9304312A FR2704112B1 (en) | 1993-04-13 | 1993-04-13 | Amplification device for television signals with variable operating class, predetermined for the elimination of transmission errors. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2160259A1 true CA2160259A1 (en) | 1994-10-27 |
Family
ID=9445996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002160259A Abandoned CA2160259A1 (en) | 1993-04-13 | 1994-04-13 | Television signal amplification device, with variable operating class which is predetermined in order to eliminate transmission errors |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0705499B1 (en) |
| JP (1) | JPH08510363A (en) |
| AT (1) | ATE159393T1 (en) |
| CA (1) | CA2160259A1 (en) |
| DE (1) | DE69406287D1 (en) |
| FR (1) | FR2704112B1 (en) |
| WO (1) | WO1994024760A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5969575A (en) * | 1997-12-11 | 1999-10-19 | Alcatel | Class A/F amplifier having second and third order harmonic input and output filtering and self bias distortion correction |
| FR2864404B1 (en) * | 2003-12-17 | 2007-02-16 | Sodielec | SIGNAL GENERATOR FOR ANALOG TELEVISION OR DIGITAL TELEVISION |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3020313C2 (en) * | 1980-05-29 | 1982-05-19 | Rohde & Schwarz GmbH & Co KG, 8000 München | Amplifier stage for amplifying amplitude-modulated frequency signals |
| FI86013C (en) * | 1989-03-29 | 1992-06-25 | Nokia Mobira Oy | FOERFARANDE FOER OMVANDLING AV EN OPERATIONSKLASS AV EN SAENDARE. |
| JPH03198407A (en) * | 1989-12-26 | 1991-08-29 | Mitsubishi Electric Corp | Linear amplifier |
-
1993
- 1993-04-13 FR FR9304312A patent/FR2704112B1/en not_active Expired - Fee Related
-
1994
- 1994-04-13 JP JP6522831A patent/JPH08510363A/en active Pending
- 1994-04-13 AT AT94913641T patent/ATE159393T1/en not_active IP Right Cessation
- 1994-04-13 CA CA002160259A patent/CA2160259A1/en not_active Abandoned
- 1994-04-13 WO PCT/FR1994/000412 patent/WO1994024760A1/en active IP Right Grant
- 1994-04-13 DE DE69406287T patent/DE69406287D1/en not_active Expired - Lifetime
- 1994-04-13 EP EP94913641A patent/EP0705499B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| FR2704112A1 (en) | 1994-10-21 |
| EP0705499B1 (en) | 1997-10-15 |
| ATE159393T1 (en) | 1997-11-15 |
| DE69406287D1 (en) | 1997-11-20 |
| FR2704112B1 (en) | 1995-05-24 |
| WO1994024760A1 (en) | 1994-10-27 |
| EP0705499A1 (en) | 1996-04-10 |
| JPH08510363A (en) | 1996-10-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |