CN202077058U - Phase lock frequency modulation emitter - Google Patents
Phase lock frequency modulation emitter Download PDFInfo
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- CN202077058U CN202077058U CN2011201935111U CN201120193511U CN202077058U CN 202077058 U CN202077058 U CN 202077058U CN 2011201935111 U CN2011201935111 U CN 2011201935111U CN 201120193511 U CN201120193511 U CN 201120193511U CN 202077058 U CN202077058 U CN 202077058U
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- phase
- frequency modulation
- controlled oscillator
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Abstract
The utility model discloses a phase lock frequency modulation emitter. Baseband signals are enhanced by a pre-stage driving circuit and then are transmitted to a D/A converter for digital analog conversion, and the baseband signals are amplified by a final stage amplifier and then are outputted to a phase lock frequency modulation circuit. A frequency reference source provides a reference frequency for a frequency synthesizer chip, and a double-electric-tuning-end voltage controlled oscillator is provided with two tuning ends. Output signals of a baseband signal conditioning circuit are inputted to a fine tuning end of the double-electric-tuning-end voltage controlled oscillator. In a phase discriminator of the frequency synthesizer chip, after phase comparison between output signals of the double-electric-tuning-end voltage controlled oscillator and a phase demodulation frequency, direct current error voltage is outputted, the error voltage is inputted to a coarse tuning end of the double-electric-tuning-end voltage controlled oscillator via a loop low pass filter, and closed loop phase lock control of a phase-locked loop is completed, and output is frequency modulation signals. The phase lock frequency modulation emitter reduces influences of the environment to frequency modulation signal bandwidth outputted by the phase lock frequency modulation emitter.
Description
Technical field
The present invention relates to Digital Signal Processing, especially the baseband signal conditioning device of controlling about the frequency modulation of the phase locking signal bandwidth.
Background technology
At present, known frequency modulation of the phase locking reflector is made up of frequency divider, voltage controlled oscillator, loop low pass filter etc., and base band data to be modulated is directly inserted the loop low pass filter front end or the rear end of phase-locked loop, and phase-locked loop output is FM signal.When work, the FM signal bandwidth of existing frequency modulation of the phase locking reflector depends on the base band data amplitude of input, and the base band data amplitude is bigger with variation of ambient temperature, and final result causes FM receiver sensitivity to reduce.
Summary of the invention
The deficiency that influenced by variation of ambient temperature for the FM signal bandwidth that overcomes prior art output, the invention provides a kind of input baseband signal modulate circuit, this signal conditioning circuit can reduce the variation of the FM signal bandwidth of frequency modulation of the phase locking reflector with ambient temperature.
The technical solution adopted for the present invention to solve the technical problems is: comprise baseband signal modulate circuit and frequency modulation of the phase locking circuit.Described baseband signal modulate circuit comprises preceding stage drive circuit, D/A converter, final amplifier and voltage-reference.Enter D/A converter after baseband signal is strengthened by preceding stage drive circuit and carry out digital-to-analogue conversion, export the frequency modulation of the phase locking circuit to after amplifying by final amplifier then.The clock signal of baseband signal directly enters the data clock pin of D/A converter, and D/A converter converts thereof into analog level output at the signal of the rising edge clock signal sampled digital input of baseband signal.Voltage-reference is connected to D/A converter, for it provides reference voltage.
Described frequency modulation of the phase locking circuit comprises frequency reference source, synthesizer chip, loop low pass filter, two electricity accent end voltage controlled oscillator and single-chip microcomputer.The frequency reference source provides reference frequency for synthesizer chip, and in synthesizer chip frequency division or frequency multiplication as phase demodulation frequency; Two electricity transfer the end voltage controlled oscillator to have two tuning ends, and the output signal of baseband signal modulate circuit is input to the fine tuning end that two electricity are transferred the end voltage controlled oscillator, is used for frequency modulation; In the phase discriminator of synthesizer chip, two electricity transfer the output signal of end voltage controlled oscillator to carry out bit comparison mutually with phase demodulation frequency behind frequency division, according to both phase difference phase discriminator output direct-flow error voltages; Direct-flow error voltage is transferred the coarse adjustment end of end voltage controlled oscillator by being input to two electricity after loop low pass filter filtering phase demodulation frequency and the high-frequency noise, finishes the phase-locked control of closed loop of phase-locked loop.Two electricity transfer the output of end voltage controlled oscillator to be FM signal.Described single-chip microcomputer is to be used for the internal register of configuration frequency chip combiner.
Stage drive circuit is to constitute emitter follower by operational amplifier before described, and effect is the driving force that strengthens baseband signal; Described final amplifier is to constitute proportional amplifier in the same way by operational amplifier, is used for adjusting the amplitude of baseband signal, makes it satisfy the input voltage range that two electricity are transferred end voltage controlled oscillator fine tuning end.
The invention has the beneficial effects as follows: owing to adopted the less voltage-reference of temperature coefficient, make the amplitude output signal of D/A converter in the baseband signal modulate circuit very little with variation of ambient temperature, thereby reduced the influence of ambient temperature, overcome prior art and exported the deficiency that the FM signal bandwidth is subjected to the influence of variation of ambient temperature the FM signal bandwidth of frequency modulation of the phase locking reflector output.
The present invention is further described below in conjunction with drawings and Examples.
Description of drawings
Fig. 1 is a structural representation of the present invention;
Among the figure, 1-baseband signal, the clock signal of 2-baseband signal, stage drive circuit before the 3-, 4-voltage-reference, 5-D/A transducer, the 6-final amplifier, 7-baseband signal modulate circuit, 8-frequency reference source, the 9-synthesizer chip, 10-single-chip microcomputer, 11-loop low pass filter, the two electricity of 12-are transferred the end voltage controlled oscillator, 13-frequency modulation of the phase locking circuit, the output signal of 14-baseband signal modulate circuit 7, the output signal that the two electricity of 15-are transferred end voltage controlled oscillator 12.
Embodiment
Device embodiment:, the inventive system comprises baseband signal modulate circuit 7, frequency modulation of the phase locking circuit 13 with reference to Fig. 1.Described baseband signal modulate circuit 7 contains preceding stage drive circuit 3, D/A converter 5, final amplifier 6 and voltage-reference 4.Described D/A converter 5 connects the clock signal 2 of preceding stage drive circuit 3, final amplifier 6, voltage-reference 4 and baseband signal.Stage drive circuit 3 is the emitter followers that are made of operational amplifier before described, and effect is the driving force that strengthens baseband signal 1; Described final amplifier 6 constitutes proportional amplifier in the same way by operational amplifier, is used for adjusting the amplitude of baseband signal.
Described frequency modulation of the phase locking circuit 13 transfers end voltage controlled oscillator 12 and single-chip microcomputer 10 to form by frequency reference source 8, synthesizer chip 9, loop low pass filter 11, two electricity.Described synthesizer chip 9 connects frequency reference source 8, loop low pass filter 11, single-chip microcomputer 10 and two electricity and transfers end voltage controlled oscillator 12; Described two electricity is transferred end voltage controlled oscillator 12 T-Ring road low pass filter 11 and final amplifiers 6.
The input of stage drive circuit 3 before baseband signal 1 enters, the output of preceding stage drive circuit 3 connects the DB0～DB11 digital input end of D/A converter 5; Described D/A converter is selected current-output type high-speed d/a AD9762 for use; The clock signal 2 of baseband signal is input to 28 pin of D/A converter 5.Voltage-reference 4 is connected to 17 pin of D/A converter 5, for it provides reference voltage; Described voltage-reference is selected ADR3412 for use, and the temperature coefficient of output voltage is 8ppm/ ℃ in-40 ℃～125 ℃.D/A converter 5 analog outputs 22 pin connect final amplifier 6; Described final amplifier 6 adopts proportional amplifier in the same way, and gain amplifier is 6dB; Operational amplifier before described in stage drive circuit 3, the final amplifier 6 is selected AD8615 for use.The amplitude temperature coefficient of the output signal 14 of baseband signal modulate circuit 7 depends on the temperature coefficient of voltage-reference 4.
Frequency modulation of the phase locking circuit 13 is general known phase-locked loop circuits.Compensation crystal oscillator is selected in described frequency reference source 8 for use, for synthesizer chip 9 provides reference frequency, and in synthesizer chip 9 frequency division or frequency multiplication as phase demodulation frequency fp; In the phase discriminator of synthesizer chip 9, two electricity transfer end voltage controlled oscillator 12 output signals 15 to carry out bit comparison mutually with phase demodulation frequency fp behind frequency division, output direct-flow error voltage Ud; Ud transfers the coarse adjustment end of end voltage controlled oscillator 12 by being input to two electricity after loop low pass filter 11 filtering phase demodulation frequencies and the high-frequency noise, finishes the phase-locked control of closed loop of phase-locked loop circuit.It is the passive low ventilating filter of 10kHz that described loop low pass filter 11 adopts cut-off frequency, can also adopt active low-pass filter; The cut-off frequency of loop low pass filter must be less than the bit rate of 1/2nd baseband signals.Described two electricity transfers end voltage controlled oscillator 12 to have two tuning ends, and the output signal 14 of baseband signal modulate circuit 7 is input to the fine tuning end that two electricity are transferred end voltage controlled oscillator 12, is used for frequency modulation.Two electricity transfer the output signal 15 of end voltage controlled oscillator 12 to be FM signal.
Claims (2)
1. frequency modulation of the phase locking reflector, comprise baseband signal modulate circuit and frequency modulation of the phase locking circuit, it is characterized in that: described baseband signal modulate circuit comprises preceding stage drive circuit, D/A converter, final amplifier and voltage-reference, enter D/A converter after baseband signal is strengthened by preceding stage drive circuit and carry out digital-to-analogue conversion, export the frequency modulation of the phase locking circuit to after amplifying by final amplifier then, the clock signal of baseband signal directly enters the data clock pin of D/A converter, D/A converter is at the signal of the rising edge clock signal sampled digital input of baseband signal, convert thereof into analog level output, voltage-reference is connected to D/A converter, for it provides reference voltage; Described frequency modulation of the phase locking circuit comprises the frequency reference source, synthesizer chip, loop low pass filter, two electricity are transferred end voltage controlled oscillator and single-chip microcomputer, the frequency reference source provides reference frequency for synthesizer chip, and in synthesizer chip frequency division or frequency multiplication as phase demodulation frequency, two electricity transfer the end voltage controlled oscillator to have two tuning ends, the output signal of baseband signal modulate circuit is input to the fine tuning end that two electricity are transferred the end voltage controlled oscillator, be used for frequency modulation, in the phase discriminator of synthesizer chip, two electricity transfer the output signal of end voltage controlled oscillator to carry out bit comparison mutually with phase demodulation frequency behind frequency division, according to both phase difference phase discriminator output direct-flow error voltages, direct-flow error voltage is transferred the coarse adjustment end of end voltage controlled oscillator by being input to two electricity after loop low pass filter filtering phase demodulation frequency and the high-frequency noise, finish the phase-locked control of closed loop of phase-locked loop, two electricity transfer the output of end voltage controlled oscillator to be FM signal; Described single-chip microcomputer is to be used for the internal register of configuration frequency chip combiner.
2. frequency modulation of the phase locking reflector according to claim 1 is characterized in that: stage drive circuit is to constitute emitter follower by operational amplifier before described; Described final amplifier is to constitute proportional amplifier in the same way by operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201935111U CN202077058U (en) | 2011-06-09 | 2011-06-09 | Phase lock frequency modulation emitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201935111U CN202077058U (en) | 2011-06-09 | 2011-06-09 | Phase lock frequency modulation emitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202077058U true CN202077058U (en) | 2011-12-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011201935111U Expired - Fee Related CN202077058U (en) | 2011-06-09 | 2011-06-09 | Phase lock frequency modulation emitter |
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| Country | Link |
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| CN (1) | CN202077058U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102299879A (en) * | 2011-06-09 | 2011-12-28 | 西北工业大学 | Phase-lock frequency modulation transmitter |
| CN102739266A (en) * | 2012-05-17 | 2012-10-17 | 清华大学 | Multimode emitter based on numerically controlled oscillator |
| CN109831401A (en) * | 2019-03-19 | 2019-05-31 | 西安电子科技大学 | Modulator and method based on total reference in a kind of MIMO system |
-
2011
- 2011-06-09 CN CN2011201935111U patent/CN202077058U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102299879A (en) * | 2011-06-09 | 2011-12-28 | 西北工业大学 | Phase-lock frequency modulation transmitter |
| CN102739266A (en) * | 2012-05-17 | 2012-10-17 | 清华大学 | Multimode emitter based on numerically controlled oscillator |
| CN102739266B (en) * | 2012-05-17 | 2014-06-04 | 清华大学 | Multimode emitter based on numerically controlled oscillator |
| CN109831401A (en) * | 2019-03-19 | 2019-05-31 | 西安电子科技大学 | Modulator and method based on total reference in a kind of MIMO system |
| CN109831401B (en) * | 2019-03-19 | 2021-04-13 | 西安电子科技大学 | Modulator and method based on common reference in MIMO system |
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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: 20111214 Termination date: 20140609 |