CN87103217A - Digital-analog combining transmission method - Google Patents
Digital-analog combining transmission method Download PDFInfo
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- CN87103217A CN87103217A CN87103217.1A CN87103217A CN87103217A CN 87103217 A CN87103217 A CN 87103217A CN 87103217 A CN87103217 A CN 87103217A CN 87103217 A CN87103217 A CN 87103217A
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Abstract
The present invention proposes a kind of digital-analog combining transmission method of suitable China PAL-D television system.This method has increased digital-to-analogue blender, digital-to-analogue splitter in equipment, frequency division on base band closes the road PAL-D TV analog signal and digital voice signal, and the ratio of reasonable selecting video and speech modulation frequency deviation is to reach frequency band and the power that makes full use of channel.Its advantage is that equipment is simple, strong anti-interference performance, transmission signals quality height.
Description
The present invention relates to a kind of digital-analog combining transmission method that is used for communications.Be specially adapted for the anolog TV signals of PAL-D standard, the digital-to-analogue mixed transport of digit and speech sound signal.
Present communications has three kinds of methods usually: the analogue transmission method, and this method is relatively simple, and band occupancy is narrow, but interference free performance is poor, and communication transmission quality is poor.Digit transmission method, strong anti-interference performance, communication transmission quality height, digital-analog combining transmission method both can be saved bandwidth, reduced equipment amount, and cost is low, can reach the strong anti-interference performance of digit transmission method again, the purpose of the high communication quality.The Ku frequency range of present Japanese BS-2 broadcast satellite and Canadian An Nike satellite all under ntsc television system situation, has realized the mixed transport of anolog TV signals and digit and speech sound signal.Because the video bandwidth that the ntsc television system takies is the 4.2-4.5 megahertz, mix realization digital-to-analogue mixed transport easily with digital speech.And the existing radio and television of China are the PAL-D television system, occupy the video bandwidth of 6 megahertzes, realize that digital-to-analogue mixed transport difficulty is big, technical sophistication.
The digital-analog combining transmission method of the purpose of this invention is to provide the existing PAL-D television system of a kind of suitable China, realizing easily both can be saved bandwidth, reduced equipment amount, reduced cost, and can reach strong anti-interference performance again and communicate by letter with high-quality.
The present invention is achieved in that voice signal comprises that telephone signal (Tell-N) and television audio signals (Aud) itself synthesize with time division way realization multichannel; in encoder (PCM), carry out pulse code modulation; become the information code current of a 2048Kb/S; it is digital signal; in modulator (QPSK1), carry out difference quadrature four then and be modulated to paying on the carrier wave (fs) of a fixed frequency mutually; the present invention fixedly carrier frequency (fs) is chosen at 7.09379MHZ; the television analog signals therewith of this digital modulation signals and PAL-D standard (vid) is in digital-to-analogue blender (DAM); frequency division closes the road multiplex (MUX) on base band, realizes the digital-to-analogue mixed transport.In digital-to-analogue blender (DAM), frequency division closes the road multiplex (MUX) on base band, realizes the digital-to-analogue mixed transport.Numeral and analog signal are fully isolated.And the choosing of peak to peak frequency deviation △ fppr of anolog TV signals must be satisfied formula:
△fppr＝ (B-2fsc-△fe)/(0.65-0.95)
In the formula: B is a transmission bandwidth.
Fsc is that colourity is paid carrier wave, is 4.43MHZ.
△ fe is frequency spectrum diffusion (the being generally the 1-2 megahertz) sum that the peak to peak frequency deviation that causes of energy dispersal signal and spike cause.
Mutual interference is little mutually with analog signal in order to make numeral simultaneously, and language is paid the peak to peak frequency deviation of carrier frequency frequency deviation △ fops and TV signal, and it is 0.17-0.25 that the ratio of △ fppr is chosen scope, adjusts the amplitude ratio of the two in this scope.
Then digital-to-analogue mixed signal on this base band is carried out frequency modulation(FM) and transfer out, undertaken by its inverse process, realized the digital-analog combining transmission method of the PAL-D television system that China is existing at receiving terminal.
PAL-D standard digital-to-analogue mixed transport of the present invention, its technology is simple, and equipment amount is few, and debugging is convenient, realizes that easily cost is low, can be used in the satellite channel, reaches in the fiber channel in the channel of digital microwave relay with the equipment of this inventive method development.Its strong anti-interference performance; transmission signal quality height; TV, sound accompaniment and telephone signal transmission quality all meet China radio and television department, CCIP(Consultative Committee on International Radio (CCIR)) and the CCITT(international telegram phone committee) requirement, be a kind of desirable digital-analog combining transmission method.
The present invention is provided by following examples and accompanying drawing.
Accompanying drawing is the principle calcspar of the embodiment of the invention.It is by encoder (PCM1), modulator (QPSK1), digital-to-analogue blender (DAM), frequency interleaved modulation modulator (FM), upconverter (U/C), and channel (ch), low-converter (D/C), frequency discriminator (DFM), digital-to-analogue splitter (DAS), demodulator (QPSK2), decoder (PCM2) are formed.
Voice signal comprises the telephone signal (Tel1-N) and the television audio signals (Aud) of several; itself realizes that with time division way multichannel is synthetic; carry out the information code current that pulse code modulation becomes a 2048kb/S in the input coding device (PCM1); it is the language digital signal; carrying out difference quadrature four then in modulator (QPSK1) is modulated on the language carrier frequency (fs) mutually; the language carrier frequency (fs) of the embodiment of the invention is chosen at 7.09379MHZ; the television analog signals therewith of this digital modulation signals and PAL-D standard (Vid) is in digital-to-analogue blender (DAM); frequency division closes the road multiplex (MUX) on base band, realizes the digital-to-analogue mixed transport.In digital mixer; numeral and analog signal are fully isolated; and adjust numeral and the two amplitude ratio of analogue type signal; make mutual interference little; then the digital-to-analogue mixed signal on this base band is sent in the frequency interleaved modulation modulator (FM) and carried out frequency modulation(FM), be modulated on 70 mhz frequencys, send into again in the upconverter (U/C); its frequency is operated on 1935 megahertzes, and channel (ch) transfers out digital-to-analogue mixed signal.
On 1935 mhz frequencys, digital-to-analogue mixed signal is sent into low-converter (D/C) at the receiving terminal operation of receiver; make it be reduced into the modulating frequency of 70 megahertzes; send into again in frequency discriminator (DFM) and the digital-to-analogue splitter (DAS); decomposite the television analog signals therewith of PAL-D standard; the language digital signal is sent in the demodulator (QPSK2) again; demodulate the digital signal code stream of 2048kb/S; this digital signal is sent in the decoder (PCM) again; resolve into television field frame (Aud) and multiplex telephony (Tel1-N) signal, reach digital-to-analogue mixed transport purpose.
Claims (3)
1, the digital-analog combining transmission method of the digital-to-analogue mixed transport circuit of being formed by encoder [PCM1], modulator [QPSK1], frequency interleaved modulation modulator [FM], upconverter [U/C], channel [Ch], low-converter [D/C], frequency discriminator [DFM], demodulator [QPSK2], decoder [PCM2]; it is characterized in that base band frequency division multiplex (MUX); TV with the PAL-D standard is an analog signal, and language is a digital signal.
2, digital-analog combining transmission method according to claim 1 is characterized in that:
(1) the peak to peak frequency deviation △ fppr of anolog TV signals is:
△fppr＝ (B-2fsc-△fe)/(0.65-0.95)
B is a transmission bandwidth in the formula
Fsc is that colourity is paid carrier wave, is 4.43 megahertzes.
△ fe is frequency spectrum diffusion (the being generally the 1-2 megahertz) sum that the peak to peak frequency deviation that causes of energy dispersal signal and spike cause.
(2) the language ratio of paying the peak to peak frequency deviation △ fppr of carrier frequency frequency deviation △ fops and TV signal is chosen for 0.17-0.25.
3, digital-analog combining transmission method according to claim 1 and 2 has a digital-to-analogue blender (DAM) and a digital-to-analogue splitter (DAS) in the digital-to-analogue mixed transport circuit that it is characterized in that being constituted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN87103217.1A CN1003904B (en) | 1987-04-28 | 1987-04-28 | Digital-analog combining transmission method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN87103217.1A CN1003904B (en) | 1987-04-28 | 1987-04-28 | Digital-analog combining transmission method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN87103217A true CN87103217A (en) | 1987-11-18 |
| CN1003904B CN1003904B (en) | 1989-04-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN87103217.1A Expired CN1003904B (en) | 1987-04-28 | 1987-04-28 | Digital-analog combining transmission method |
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| Country | Link |
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| CN (1) | CN1003904B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113411131A (en) * | 2021-06-18 | 2021-09-17 | 北京邮电大学 | Digital-analog signal hybrid transmission method |
-
1987
- 1987-04-28 CN CN87103217.1A patent/CN1003904B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113411131A (en) * | 2021-06-18 | 2021-09-17 | 北京邮电大学 | Digital-analog signal hybrid transmission method |
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| Publication number | Publication date |
|---|---|
| CN1003904B (en) | 1989-04-12 |
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