CN201781502U - Signal modulating circuit and signal demodulating circuit for track traffic signal transponder - Google Patents
Signal modulating circuit and signal demodulating circuit for track traffic signal transponder Download PDFInfo
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- CN201781502U CN201781502U CN2010205298372U CN201020529837U CN201781502U CN 201781502 U CN201781502 U CN 201781502U CN 2010205298372 U CN2010205298372 U CN 2010205298372U CN 201020529837 U CN201020529837 U CN 201020529837U CN 201781502 U CN201781502 U CN 201781502U
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Abstract
The utility model relates to a signal modulating circuit and a signal demodulating circuit for a track traffic signal transponder. The signal modulating circuit comprises a digital signal processor (DSP), a frequency modulator of a direct digital type frequency synthesizer (DDS), a power amplifier and a coil coupling transmitter which are successively connected. The signal demodulating circuit comprises the digital signal processor (DSP), a frequency generator of the direct digital type frequency synthesizer (DDS), a receiving signal amplifier, a multiplication frequency mixer, a band-pass filter and a shaping filter. The utility model has the advantages that the modulating of FSK (frequency shift keying) signals can be conveniently realized through the software programming under the condition that the peripheral circuits are not changed; and the work of the signal demodulating circuit is realized mainly through the software so as to simplify the circuit and reduce the cost.
Description
Technical field
The utility model relates to a kind of signal modulation and demodulation circuit, and especially a kind of signal modulation circuit and demodulator circuit that is used for the track traffic signal responder unit belongs to city rail communication and signal equipment field.
Background technology
Transponder device is a kind of high speed point type data transmission set that constitutes with electromagnetic induction principle, can be used for to fixing and real-time variable information such as train automatic controlling system (ATC) transmission lines basic parameter, line speed, special location, train operation target data, temporary speed limitation, station route.
As shown in Figure 1, existing transponder device comprises vehicle-mounted transponder and ground transponder, vehicle-mounted transponder comprises transmitting system and receiving system, wherein transmitting system comprises carrier-fequency generator, power amplifier and car antenna, and receiving system comprises car antenna, filter, digital demodulator and message handler; Ground transponder comprises the signal generator that contains frequency shift keying (FSK) modulating unit, coded stack etc.Its operation principle is: when vehicle-mounted transponder was worked, the 27.095MHz carrier frequency that the carrier-fequency generator vibration produces amplified after the outside transmission that car antenna does not stop by power amplifier; When operating locomotive process ground transponder top, the ground transponder that is in resting state receives the 27.095MHz power signal of launching from car antenna, behind rectifying and voltage-stabilizing, become the power supply of transponder internal circuit, control the FSK modulating unit simultaneously and produce the continuous up link fsk signal of phase place, via amplification driving circuit, give car antenna by the loopback of FSK transmitting antenna with this signal; Car antenna has duplex capability, a series of processing such as the information via filtering that it receives, demodulation, verification, decoding, form accurately message after, just be transferred to vehicle control syetem, display system and other related systems are finished the mission that submits necessary information to running train.
The problem that existing equipment exists is that the generation of fsk signal needs oscillating circuit, and its frequency depends on peripheral resistance capacitance, frequency adjustment range is narrow, can only change peripheral circuit when needing to change frequency, and the temperature of peripheral circuit is floated to influence circuit very big, complex operation, effect are also bad.
The utility model content
The purpose of this utility model is: the problem at above-mentioned prior art exists proposes a kind of simple in structure, easy to operate signal modulation circuit that is used for the track traffic signal responder unit and demodulator circuit.
In order to reach above purpose, the signal modulation circuit that is used for the track traffic signal responder unit of the present utility model comprises digital signal processor (DSP), Direct Digital Synthesizer (DDS) frequency modulator, power amplifier and the coil coupling transmitter that connects successively.
Further, described Direct Digital Synthesizer (DDS) frequency modulator comprises two frequency registers.
The signal demodulating circuit that is used for the track traffic signal responder unit comprises digital signal processor (DSP), Direct Digital Synthesizer (DDS) frequency generator, the acknowledge(ment) signal amplifier, the multiplication frequency mixer, band pass filter, shaping filter, the output of described digital signal processor (DSP) links to each other with the first input end of multiplication frequency mixer through Direct Digital Synthesizer (DDS) frequency generator, the output of described multiplication frequency mixer links to each other with the input of shaping filter with digital signal processor (DSP) through band pass filter successively, and described signal amplifier links to each other with second input of multiplication frequency mixer.
Signal modulation circuit of the present utility model adopts digital signal processor (DSP), can give full play to the advantage and the flexibility of Direct Digital Synthesizer (DDS) modulation, under the situation that does not change peripheral circuit, only just can conveniently realize the modulation of fsk signal by software programming; Signal demodulating circuit becomes low-frequency modulation signal with the high-frequency modulation signal that receives after by mixing, carry out software demodulation through delivering to digital signal processor (DSP) behind the shaping filter, utilize the high handling property of DSP, mainly giving software with the work of demodulation realizes, thereby simplified circuit, reduced cost.
Description of drawings
Below in conjunction with accompanying drawing the utility model is further described.
Fig. 1 is the schematic diagram of existing transponder device.
Fig. 2 is the signal modulation circuit schematic diagram of the utility model embodiment.
Fig. 3 is the signal demodulating circuit schematic diagram of Fig. 2 embodiment.
Fig. 4 is the software demodulation schematic flow sheet of Fig. 2 embodiment.
Embodiment
Embodiment one
The signal modulation circuit that is used for the track traffic signal responder unit of present embodiment and demodulator circuit are shown in Fig. 2-3.
Signal modulation circuit comprises digital signal processor (DSP), Direct Digital Synthesizer (DDS) frequency modulator, power amplifier and the coil coupling transmitter that connects successively.
Direct Digital Synthesizer (DDS) frequency modulator comprises two frequency register (not shown).
Signal demodulating circuit comprises digital signal processor (DSP), Direct Digital Synthesizer (DDS) frequency generator, the acknowledge(ment) signal amplifier, the multiplication frequency mixer, band pass filter, shaping filter, the output a of digital signal processor (DSP) links to each other with the first input end b of multiplication frequency mixer through Direct Digital Synthesizer (DDS) frequency generator, the output c of multiplication frequency mixer links to each other with the input d of shaping filter with digital signal processor (DSP) through band pass filter successively, and signal amplifier links to each other with the second input e of multiplication frequency mixer.
In the present embodiment, digital signal processor (DSP) is the TMS 320C2407A type DSP of TI company.
Modulation circuit running: DSP sends out frequency control word and gives the DDS frequency modulator, makes two frequency registers of DDS load different frequency values, and for example frequency register 0 loads high frequency values, and frequency register 1 loads low frequency value; And then the DDS control register is set just can selects frequency register by sending out a frequency control word, thereby generation fsk modulated signal, fsk signal amplifies through the amplitude of power amplifier and electric current amplifies back realization power amplification, is sent by coil coupling transmitter at last.
Demodulator circuit running: the fsk signal that receives from track, computing through the acknowledge(ment) signal amplifier is amplified, in the multiplication frequency mixer, carry out mixing with the sinusoidal signal of the certain frequency that produces by the DDS frequency generator, thereby produce two kinds of input signals with frequently and difference frequency signal, band pass filter will keep difference frequency signal with the frequency target signal filter then, enter DSP through shaping filter again, by the software demodulation difference frequency signal, finally restore modulation signal again.
The software demodulation flow process is seen Fig. 4.
If the cycle of high-frequency signal is T1, counting unit is n1; The cycle of low frequency signal is T2, and counting unit is n2.
If the period T=T1 of the signal that receives, then explanation is a high-frequency signal, and then n1 adds 1, if the number of n1 equals 1, then adds up n2, has looked at what low frequency signals, thereby has counted the number of digital signaling zero; If the period T=T2 of the signal that receives, then explanation is a low frequency signal, and then n2 adds 1, if the number of n2 equals 1, then adds up n1, has looked at what high-frequency signals, thereby has counted the number of digital signal 1; Thereby realized the software demodulation of fsk modulated signal.
DDS is a kind of frequency synthesizer of total digitalization, and it is reference with the crystal oscillator frequency of a high stable, by writing the sine wave that different frequency control words just can produce stable different frequency.The advantage of DDS is: phase place was continuous when frequency was switched, and compole is short during frequency inverted, and frequency resolution is very high, relative bandwidth is very wide, and total digitalization realizes that frequency, phase place and amplitude all can realize program control, therefore can be closely linked with computer, give full play to the software effect.
In addition to the implementation, the utility model can also have other execution modes.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection range of the utility model requirement.
Claims (3)
1. a signal modulation circuit that is used for the track traffic signal responder unit is characterized in that, comprises the digital signal processor, Direct Digital Synthesizer frequency modulator, power amplifier and the coil coupling transmitter that connect successively.
2. the signal modulation circuit that is used for the track traffic signal responder unit according to claim 1 is characterized in that, described Direct Digital Synthesizer frequency modulator comprises two frequency registers.
3. signal demodulating circuit that is used for the track traffic signal responder unit, it is characterized in that, comprise digital signal processor, the Direct Digital Synthesizer frequency generator, the acknowledge(ment) signal amplifier, the multiplication frequency mixer, band pass filter, shaping filter, the output of described digital signal processor links to each other through the first input end of Direct Digital Synthesizer frequency generator with the multiplication frequency mixer, the output of described multiplication frequency mixer links to each other with the input of digital signal processor with shaping filter through band pass filter successively, and described signal amplifier links to each other with second input of multiplication frequency mixer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205298372U CN201781502U (en) | 2010-09-14 | 2010-09-14 | Signal modulating circuit and signal demodulating circuit for track traffic signal transponder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205298372U CN201781502U (en) | 2010-09-14 | 2010-09-14 | Signal modulating circuit and signal demodulating circuit for track traffic signal transponder |
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| Publication Number | Publication Date |
|---|---|
| CN201781502U true CN201781502U (en) | 2011-03-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010205298372U Expired - Fee Related CN201781502U (en) | 2010-09-14 | 2010-09-14 | Signal modulating circuit and signal demodulating circuit for track traffic signal transponder |
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| CN (1) | CN201781502U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110460353A (en) * | 2019-07-24 | 2019-11-15 | 柳州铁道职业技术学院 | A kind of railway active balise message generating device of hand-held |
-
2010
- 2010-09-14 CN CN2010205298372U patent/CN201781502U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110460353A (en) * | 2019-07-24 | 2019-11-15 | 柳州铁道职业技术学院 | A kind of railway active balise message generating device of hand-held |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110330 Termination date: 20140914 |
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| EXPY | Termination of patent right or utility model |