CN201491137U - Television transmitter exciter with mid frequency precision offset - Google Patents
Television transmitter exciter with mid frequency precision offset Download PDFInfo
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- CN201491137U CN201491137U CN2009202029653U CN200920202965U CN201491137U CN 201491137 U CN201491137 U CN 201491137U CN 2009202029653 U CN2009202029653 U CN 2009202029653U CN 200920202965 U CN200920202965 U CN 200920202965U CN 201491137 U CN201491137 U CN 201491137U
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Abstract
The utility model relates to a television transmitter exciter, in particular to a television transmitter exciter with mid frequency precision offset. The exciter is characterized in that the exciter comprises a precision offset mid frequency oscillator, a local oscillator phase-locked loop, a mid frequency modulator circuit, an up-conversion circuit, a filtering amplifying circuit, and a clock reference circuit, wherein the clock reference circuit is respectively connected with the precision offset mid frequency oscillator and the input end of a local oscillator phase-locked loop circuit, the output end of the precision offset mid frequency oscillator is connected with the mid frequency modulator circuit, the output end of the local oscillator phase-locked loop circuit is connected with the up-conversion circuit, and the mid frequency modulator circuit, the up-conversion circuit, the filtering amplifying circuit are connected in sequence. Compared with the prior art, the exciter has the advantages that the circuit is simple, and the carrier-frequency offsets of different channels share the same circuit parameter, thereby applying to a quick variant exciter.
Description
Technical field
The utility model relates to a kind of television transmitter exciter, relates in particular to a kind of television transmitter exciter of realizing precision offset at intermediate frequency.
Background technology
Development along with China's radio and television services, various places TV station sets up the TV frequency one after another or increases transmitting power, the frequency spectrum resource that is used for television broadcasting is deficient day by day, thereby causes the adjoining area co-channel interference phenomenon to occur, reticulate pattern occurs on the television receiver picture.Theory and practice proves that carrier frequency precision offset technology is the effective means that solves television identical-frequency interference, and in the co-channel interference serious area, the transmitter with carrier frequency precision offset function can make the image quality of receiver improve greatly.
Traditional carrier frequency precision offset TV exciter, its functional-block diagram as shown in Figure 1, different with common TV transmitter exciter is: 1) increased " synchronised clock " input signal; 2) clock reference of " local oscillator phase-locked loop " is provided by " bias oscillator "." bias oscillator " can be realized by phase-locked loop circuit or DDS circuit, and " synchronised clock " input can be realized by 6PS or " Big Dipper " time service circuit.
For different television channels, " bias oscillator " of traditional carrier frequency precision offset TV exciter all will do corresponding adjusting, to reach required carrier frequency precision and stability.
Summary of the invention
The purpose of this utility model is based on the above-mentioned background technology, proposes the carrier frequency precision offset scheme that a kind of intermediate frequency is realized, for different television channels, the parameter of circuit is the television transmitter exciter of the intermediate frequency precision offset of unanimity.
For achieving the above object, the utility model is achieved through the following technical solutions:
A kind of television transmitter exciter of intermediate frequency precision offset, it is characterized in that, comprise precision offset intermediate-frequency oscillator, local oscillator phase-locked loop, modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit, clock reference circuit, the clock reference circuit connects the input of precision offset intermediate-frequency oscillator and local oscillator phase-locked loop circuit respectively, precision offset intermediate-frequency oscillator output connects modulation circuit of intermediate frequency, and local oscillator phase-locked loop circuit output connects up-converter circuit; Modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit connect successively.
Described precision offset intermediate-frequency oscillator comprises phase-locked loop intergrated circuit IC5, voltage controlled oscillator VC0, loop filter and power source deoupling circuit, 6 pin of phase-locked loop intergrated circuit IC5 are coupled in the output of voltage controlled oscillator VC0 through resistance R 87, capacitor C 26, capacitor C 27, capacitor C 28, capacitor C 29, capacitor C 30, capacitor C 31, capacitor C 32, resistance R 85, resistance R 86 are formed power source deoupling circuit, are connected to 16 pin, 15 pin, 10 pin and 7 pin of phase-locked loop intergrated circuit IC5; Loop filter is by capacitor C 22, and capacitor C 23, resistance R 88 are formed, and the programming of phase-locked loop intergrated circuit IC5 is finished by 11 pin (CLK), 12 pin (DATA), 13 pin (LE); Clock reference REF10MHz is coupled to 8 pin of phase-locked loop intergrated circuit IC5 by C25.
Compared with prior art, the utility model has the advantages that: circuit is simple, and the carrier-frequency offset of different channel has identical circuit parameter, is suitable for prompt variant exciter.
Description of drawings
Fig. 1 is the functional-block diagram of traditional carrier frequency precision offset TV exciter.
Fig. 2 is the functional-block diagram of intermediate frequency precision offset TV exciter.
Fig. 3 is the schematic diagram of precision offset intermediate-frequency oscillator.
Embodiment
A kind of television transmitter exciter of intermediate frequency precision offset, comprise precision offset intermediate-frequency oscillator, local oscillator phase-locked loop, modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit, clock reference circuit, the clock reference circuit connects the input of precision offset intermediate-frequency oscillator and local oscillator phase-locked loop circuit respectively, precision offset intermediate-frequency oscillator output connects modulation circuit of intermediate frequency, and local oscillator phase-locked loop circuit output connects up-converter circuit; Modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit connect successively.
Described precision offset intermediate-frequency oscillator comprises phase-locked loop intergrated circuit IC5 (LMX2306), voltage controlled oscillator VC0, loop filter and power source deoupling circuit, 6 pin of phase-locked loop intergrated circuit IC5 are coupled in the output of voltage controlled oscillator VC0 through resistance R 87, capacitor C 26, capacitor C 27, capacitor C 28, capacitor C 29, capacitor C 30, capacitor C 31, capacitor C 32, resistance R 85, resistance R 86 are formed power source deoupling circuit, are connected to 16 pin, 15 pin, 10 pin and 7 pin of phase-locked loop intergrated circuit IC5; Loop filter is by capacitor C 22, and capacitor C 23, resistance R 88 are formed, and the programming of phase-locked loop intergrated circuit IC5 is finished by 11 pin (CLK), 12 pin (DATA), 13 pin (LE); Clock reference REF10MHz is coupled to 8 pin of phase-locked loop intergrated circuit IC5 by C25.
The functional-block diagram of the television transmitter exciter of intermediate frequency precision offset as shown in Figure 2, compare with the traditional carrier frequency precision offset exciter shown in the accompanying drawing 1, " bias oscillator " no longer needs, and " intermediate-frequency oscillator " can realize with 1/12 line frequency being the intermediate frequency biasing of stepping by " precision offset intermediate-frequency oscillator " replacement.Need to prove, owing to take off sideband signals after " up-conversion " circuit of exciter, therefore, carry out biasing upwards at intermediate frequency, in " radio frequency output " then is downward biasing, and carries out downward biasing at intermediate frequency, then is biasing upwards in " radio frequency output ".
It is to realize by frequency dividing ratio and clock reference that phase-locked loop intergrated circuit IC5 rationally is set that the intermediate frequency local oscillation signal is carried out precision offset.In the TV broadcasting system of China, line frequency is 15625Hz, and finish with 1/12 line frequency is the phase-locked loop intermediate frequency local oscillator circuit of stepping, reaches 1/12 line frequency after should making phase-locked loop intergrated circuit to the clock reference frequency division.In the present embodiment, clock reference REF10MHz is 10MHz (10000000Hz), and frequency dividing ratio is decided to be 7680, then 10000000Hz/7680=15625Hz/12.When program counter was set at 29184, then intermediate frequency local oscillator was output as the 38MHz that does not setover.
Illustrate:
1) will make intermediate frequency local oscillator is 38MHz-15625Hz/12 (being 1 1/12 line frequency of biased downward), and then the program counter of IC5 is set at 29184-1=29183;
2) will make intermediate frequency local oscillator is 38MHz+3*15625Hz/12 (promptly to 3 1/12 line frequencies of upper offset), and then the program counter of IC5 is set at 29184+3=29187.
Claims (2)
1. the television transmitter exciter of an intermediate frequency precision offset, it is characterized in that, comprise precision offset intermediate-frequency oscillator, local oscillator phase-locked loop, modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit, clock reference circuit, the clock reference circuit connects the input of precision offset intermediate-frequency oscillator and local oscillator phase-locked loop circuit respectively, precision offset intermediate-frequency oscillator output connects modulation circuit of intermediate frequency, and local oscillator phase-locked loop circuit output connects up-converter circuit; Modulation circuit of intermediate frequency, up-converter circuit, filter amplification circuit connect successively.
2. the television transmitter exciter of a kind of intermediate frequency precision offset according to claim 1, it is characterized in that, described precision offset intermediate-frequency oscillator comprises phase-locked loop intergrated circuit IC5, voltage controlled oscillator VCO, loop filter, and power source deoupling circuit, the output of voltage controlled oscillator VCO is through resistance R 87, capacitor C 26 is coupled to 6 pin of phase-locked loop intergrated circuit IC5, capacitor C 27, capacitor C 28, capacitor C 29, capacitor C 30, capacitor C 31, capacitor C 32, resistance R 85, resistance R 86 is formed power source deoupling circuit, is connected to 16 pin of phase-locked loop intergrated circuit IC5,15 pin, 10 pin and 7 pin; Loop filter is by capacitor C 22, and capacitor C 23, resistance R 88 are formed, and the programming of phase-locked loop intergrated circuit IC5 is finished by 11 pin, 12 pin, 13 pin; Clock reference REF10MHz is coupled to 8 pin of phase-locked loop intergrated circuit IC5 by C25.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202029653U CN201491137U (en) | 2009-09-01 | 2009-09-01 | Television transmitter exciter with mid frequency precision offset |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202029653U CN201491137U (en) | 2009-09-01 | 2009-09-01 | Television transmitter exciter with mid frequency precision offset |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201491137U true CN201491137U (en) | 2010-05-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202029653U Expired - Fee Related CN201491137U (en) | 2009-09-01 | 2009-09-01 | Television transmitter exciter with mid frequency precision offset |
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| Country | Link |
|---|---|
| CN (1) | CN201491137U (en) |
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2009
- 2009-09-01 CN CN2009202029653U patent/CN201491137U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100526 Termination date: 20130901 |