CN202231789U - Analog-to-digital television transmitter - Google Patents
Analog-to-digital television transmitter Download PDFInfo
- Publication number
- CN202231789U CN202231789U CN2011201487952U CN201120148795U CN202231789U CN 202231789 U CN202231789 U CN 202231789U CN 2011201487952 U CN2011201487952 U CN 2011201487952U CN 201120148795 U CN201120148795 U CN 201120148795U CN 202231789 U CN202231789 U CN 202231789U
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Abstract
The utility model relates to an analog-to-digital television transmitter, comprising a signal exciter, a power amplifier, a directional coupler, an output filter, an antenna, a monitor and a power supply, wherein the signal exciter is a digital television signal exciter composed of an ASI (asynchronous serial interface) management module, a base-band processing module, an ADPC (automatic data processing centre) module, a DAC (digital to analog converter) module, a first mixer, a local oscillator, an amplifier, an exciting amplifier and an ALC (adaptive logic circuit) module; the ASI module is used for seamless switch and output for an active signal and an standby signal of an ASI; the base-band processing module is used for conversion from input ASI code stream to the transmission signal of a terrestrial television channel; the DAC module is used for digital-to-analog conversion; the first mixer is used for mixing the digital signal frequency output by the DAC module with the carrier frequency output by the local oscillator, and outputting to the power amplifier of the transmitter through the amplifier and the exciting amplifier in order; and the ALC module is disposed between the output end of the exciting amplifier and the input end of the amplifier. The various functions of digital television transmitter are satisfied.
Description
Technical field
The utility model relates to a kind of mould and changes several television transmitters, belongs to the television transmitter technical field.
Background technology
At present; The domestic TV signal of generally using the emission of simulated television transmitter not only exists nonlinear distortion, signal-to-noise ratio degradation etc. to influence the problem of television image and Television Sound Quality, but also exists technical indicator lower; Poor anti jamming capability, defective such as frequency efficiency is low.For this reason, State Administration of Radio Film and Television has made planning, since 2015 with progressively implementing digital improvement, will close all analog TV broadcastings to the year two thousand twenty.Therefore, existing more than 10 ten thousand the simulated television transmitters of China will be faced with two alternatives: the one, and break and scrap; The 2nd, change number through mould and continue to use.Scrap if all simulating transmitting machines of the whole nation are all stopped using, purchase new digital TV transmitter, this brings very big economic loss and burden will for China's radio, TV and film industries, causes the great wasting of resources, also can influence the television digitization process of China simultaneously.
The utility model content
It is a kind of on the basis of simulated television transmitter that the purpose of the utility model is to provide, and can realize that the mould of digital television signal emission changes several television transmitters.
Its technical scheme is: a kind of mould changes several television transmitters; Comprise signal excitation device, power amplifier, directional coupler, output filter, antenna and monitoring and power supply, it is characterized in that: the digital television signal exciter of said signal excitation device for forming by ASI administration module, baseband processing module, ADPC module, DAC module, first frequency mixer, local oscillator, amplifier, exciting amplifier and ALC module; Wherein, the ASI administration module is used for the output of the active and standby two paths of signals seamless switching of ASI; Baseband processing module is used for the conversion from input ASI code stream to terrestrial television Channel Transmission signal; The DAC module is used for digital-to-analogue conversion; First frequency mixer is used for the digital signal frequency of DAC module output is mixed with the carrier frequency that local oscillator is exported, and exports the power amplifier of transmitter to through amplifier and exciting amplifier successively; Be provided with the ALC module between exciting amplifier output and the amplifier.
Its technique effect is: the utility model mould changes several television transmitters and meets under the prerequisite of relative national standards in the performance, technical indicator and the service condition that guarantee transmitter, maximally utilises and kept the device and the structure of former simulation television transmitter, has satisfied each item function of digital TV transmitter to greatest extent; Simplified improvement project to greatest extent; Both effectively improved the TV signal nonlinear distortion, reduced the noise of signal, and increased substantially DTV and broadcasted quality of signals; Promoted technical indicator; Improve the utilance of antijamming capability and frequency, practiced thrift expense again, reduced waste; Meet China's national conditions of present stage fully, have good society and economic benefit.
Description of drawings
Fig. 1 is the utility model circuit block diagram;
Fig. 2 is a signal excitation device electrical schematic diagram.
Embodiment
As shown in Figure 1, a kind of mould changes several television transmitters, comprises signal excitation device, power amplifier, directional coupler, output filter, antenna and monitoring and power supply.
As shown in Figure 2, the signal excitation device is the digital television signal exciter of being made up of ASI administration module, baseband processing module, ADPC module, DAC module, first frequency mixer, local oscillator, amplifier, exciting amplifier and ALC module.Wherein, the ASI administration module is used for the output of the active and standby two paths of signals seamless switching of ASI; Baseband processing module is used for the conversion from input ASI code stream to terrestrial television Channel Transmission signal.Baseband processing module adopts and meets the baseband processing module that GB20600 requires; The DAC module is used for digital-to-analogue conversion; First frequency mixer is used for the digital signal frequency of DAC module output and the power amplifier that exports transmitter after carrier frequency that local oscillator is exported mixes successively through amplifier and exciting amplifier to; Be provided with the ALC module that contains degree of depth automatic level control circuit between exciting amplifier output and the ALC amplifier, to realize the coupling of digital television signal exciter and various simulated television transmitter power amplifier level.
Because the effective bandwidth of digital TV transmitter output filter is decided to be 7.56MHz; And the output filter of simulated television transmitter adopts bandpass filtering as not adopting the trap mode; Its bandwidth is decided to be 8MHz; So the output band pass filter curve of reply simulated television transmitter is adjusted a little, under the prerequisite that guarantees its effective bandwidth, can satisfy the requirement that suppresses outside the band basically.
Simultaneously, because simulating transmitting machine is as the criterion with synchronous top power, digital transmitter then is as the criterion with average power.Therefore, need the comparison coefficient of adjustment output power levels sample circuit, change the authenticity of several output power of the TV transmitter indications to guarantee mould.
In addition, because the analog signal peak-to-average force ratio is generally 3dB, the peak-to-average force ratio of digital signal then be 8-9dB, and above nearly 10 times, therefore, mould changes several transmitters should be sent out grand master pattern and penetrate acc power rollback 6dB, so that use former antenna-feedback system.
In order to improve the power amplification efficiency that digital television signal technical indicator and mould change several transmitters; The radio frequency signal feedback circuit that is made up of ALC module, second frequency mixer, ADC module and demodulation module is set between directional coupler and ADPC module; The radio frequency feedback signal is drawn from directional coupler; After the carrier frequency that the ALC module exports the output of second frequency mixer and local oscillator to mixes, reduce to intermediate frequency, send into the ADPC module through ADC module analog-to-digital conversion and demodulation module again and carry out the adaptive digital correction.The same employing of demodulation module meets the demodulation module that GB20600 requires.
For realizing the interactive operation between user and the digital television signal exciter, be provided with top control module in the digital television signal exciter.Top control module is through being connected with liquid crystal display screen with keyboard; Can realize the various configurations and the human-computer interaction function of digital television signal exciter; Can realize the PC controlled function through the RS232 interface, can realize Network Management Function, make things convenient for user's Long-distance Control through Ethernet (Ethernet) interface.
Also be provided with clock module in the digital television signal exciter.Clock module is input 1PPS and 10MHz input clock signal from the outside, exports baseband processing module to, is used to provide the unified clock reference of the whole network.
Claims (4)
1. a mould changes several television transmitters; Comprise signal excitation device, power amplifier, directional coupler, output filter, antenna and monitoring and power supply, it is characterized in that: the digital television signal exciter of said signal excitation device for forming by ASI administration module, baseband processing module, ADPC module, DAC module, first frequency mixer, local oscillator, amplifier, exciting amplifier and ALC module; Wherein, the ASI administration module is used for the output of the active and standby two paths of signals seamless switching of ASI; Baseband processing module is used for the conversion from input ASI code stream to terrestrial television Channel Transmission signal; The DAC module is used for digital-to-analogue conversion; First frequency mixer is used for the digital signal frequency of DAC module output is mixed with the carrier frequency that local oscillator is exported, and exports the power amplifier of transmitter to through amplifier and exciting amplifier successively; Be provided with the ALC module between exciting amplifier output and the amplifier in.
2. a kind of mould according to claim 1 changes several television transmitters, it is characterized in that: the said radio frequency signal feedback circuit that is made up of ALC module, second frequency mixer, ADC module and demodulation module that between directional coupler and ADPC module, is provided with.
3. a kind of mould according to claim 1 changes several television transmitters, it is characterized in that: be provided with top control module in the said digital television signal exciter.
4. a kind of mould according to claim 1 changes several television transmitters, it is characterized in that: be provided with clock module in the said digital television signal exciter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201487952U CN202231789U (en) | 2011-05-11 | 2011-05-11 | Analog-to-digital television transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201487952U CN202231789U (en) | 2011-05-11 | 2011-05-11 | Analog-to-digital television transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202231789U true CN202231789U (en) | 2012-05-23 |
Family
ID=46082361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011201487952U Expired - Lifetime CN202231789U (en) | 2011-05-11 | 2011-05-11 | Analog-to-digital television transmitter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202231789U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103219874A (en) * | 2013-03-20 | 2013-07-24 | 北京市信息技术研究所 | Direct-current modulation power supply drain electrode modulation device of unmanned machine |
| CN103227649A (en) * | 2013-03-20 | 2013-07-31 | 北京市信息技术研究所 | OFDM (orthogonal frequency division multiplexing) transmitter provided with direct current modulation power supply of unmanned aerial vehicle |
-
2011
- 2011-05-11 CN CN2011201487952U patent/CN202231789U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103219874A (en) * | 2013-03-20 | 2013-07-24 | 北京市信息技术研究所 | Direct-current modulation power supply drain electrode modulation device of unmanned machine |
| CN103227649A (en) * | 2013-03-20 | 2013-07-31 | 北京市信息技术研究所 | OFDM (orthogonal frequency division multiplexing) transmitter provided with direct current modulation power supply of unmanned aerial vehicle |
| CN103227649B (en) * | 2013-03-20 | 2015-02-04 | 北京市信息技术研究所 | OFDM (orthogonal frequency division multiplexing) transmitter provided with direct current modulation power supply of unmanned aerial vehicle |
| CN103219874B (en) * | 2013-03-20 | 2015-03-11 | 北京市信息技术研究所 | Direct-current modulation power supply drain electrode modulation device of unmanned machine |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20120523 |
|
| CX01 | Expiry of patent term |