Modulation-demodulation circuit based on GMSK technology
阅读说明：本技术 一种基于gmsk技术的调制解调电路 (Modulation-demodulation circuit based on GMSK technology ) 是由 窦立刚 宁巧娇 潘吉华 李秋莉 吴良金 吴妮真 于 2020-07-20 设计创作，主要内容包括：本发明提供的一种基于GMSK技术的调制解调电路,包括调理电路、A/D转换电路、D/A转换电路、FPGA电路、电源电路、时钟电路、接口电路,电源电路与调理电路、A/D转换电路、D/A转换电路、FPGA电路分别连接,调理电路与A/D转换电路、D/A转换电路分别连接,A/D转换电路、D/A转换电路分别与时钟电路连接,A/D转换电路、D/A转换电路、时钟电路分别与FPGA电路连接,FPGA电路与接口电路连接,可以快速实现无线通信系统信号的调制与解调处理,并能实现外围电磁环境的侦测,相关器组成电路技术成熟度高,GMSK调制方式性能优良,具有很好应用前景。(The invention provides a modulation-demodulation circuit based on GMSK technology, which comprises a conditioning circuit, an A/D conversion circuit, a D/A conversion circuit, an FPGA circuit, a power circuit, a clock circuit and an interface circuit, wherein the power circuit is respectively connected with the conditioning circuit, the A/D conversion circuit, the D/A conversion circuit and the FPGA circuit, the conditioning circuit is respectively connected with the A/D conversion circuit and the D/A conversion circuit, the A/D conversion circuit and the D/A conversion circuit are respectively connected with the clock circuit, the A/D conversion circuit, the D/A conversion circuit and the clock circuit are respectively connected with the FPGA circuit, the FPGA circuit is connected with the interface circuit, the modulation and demodulation processing of wireless communication system signals can be quickly realized, the detection of peripheral electromagnetic environment can be realized, the maturity of the correlator composition circuit technology is high, the GMSK modulation mode has excellent performance and good application prospect.)
1. A modulation and demodulation circuit based on GMSK technology is characterized in that: the digital-to-analog converter comprises a conditioning circuit, an A/D conversion circuit, a D/A conversion circuit, an FPGA circuit, a power supply circuit, a clock circuit and an interface circuit, wherein the power supply circuit is respectively connected with the conditioning circuit, the A/D conversion circuit, the D/A conversion circuit and the FPGA circuit, the conditioning circuit is respectively connected with the A/D conversion circuit and the D/A conversion circuit, the A/D conversion circuit and the D/A conversion circuit are respectively connected with the clock circuit, the A/D conversion circuit, the D/A conversion circuit and the clock circuit are respectively connected with the FPGA circuit, and the FPGA circuit is connected with the interface circuit.
2. A modem circuit based on GMSK technology according to claim 1, wherein: the conditioning circuit comprises a digital control variable gain amplifier D6, a digital control variable gain amplifier D7, a plurality of capacitors, a plurality of resistors, a time relay JSZ32, a time relay JSZ33, a transmission transformer T2 and a transmission transformer T4, wherein the time relay JSZ32 is connected with the input end of a transmission transformer T2, the output end of the transmission transformer T2 is connected with the input pin of a chip digital control variable gain amplifier D6, the 8 pin and the 9 pin of the chip digital control variable gain amplifier D6 are respectively connected with one end of a capacitor C281 and one end of a capacitor C280, the other end of the capacitor C281 is respectively connected with one end of a resistor R72 and one end of a resistor R76, the other end of the capacitor C280 is respectively connected with one end of a resistor R71 and one end of a resistor R75, the other end of a resistor R71 is in short circuit with the other end of the resistor R72, the other end of a resistor R75 and the other end of the resistor R76 are, a node between the resistor R71 and the resistor R72 is connected with the A/D conversion circuit, the node is connected with one end of the capacitor CH, and the other end of the capacitor CH is grounded;
the time relay JSZ33 is connected with the input end of a transmission transformer T4, the output end of a transmission transformer T4 is connected with the input pin of a chip digital control variable gain amplifier D7, the pins 8 and 9 of the chip digital control variable gain amplifier D7 are respectively connected with one end of a capacitor C284 and one end of a capacitor C283, the other end of the capacitor C284 is respectively connected with one end of a resistor R74 and one end of a resistor R78, the other end of the capacitor C283 is respectively connected with one end of a resistor R73 and one end of a resistor R77, the other end of the resistor R74 is in short circuit with the other end of a resistor R73, the other end of the resistor R77 and the other end of the resistor R78 are respectively connected with an A/D conversion circuit, a capacitor C285 is connected in series between the other end of a resistor R77 and the other end of a resistor R3934, a node between the resistor R73 and.
3. A modem circuit based on GMSK technology according to claim 1, wherein: the A/D conversion circuit comprises an A/D conversion chip D2, a plurality of resistors and a plurality of capacitors, wherein a pin 37 and a pin 38 of the A/D conversion chip D2 are respectively connected with the other end of a resistor R75 and the other end of a resistor R76, a pin 44 and a pin 43 of the A/D conversion chip D2 are respectively connected with the other end of a resistor R77 and the other end of a resistor R78, a node between a resistor R71 and the resistor R72 and a node between a resistor R73 and the resistor R74 are respectively connected with a pin 41 of the A/D conversion chip D2, a pin 49 and a pin 50 of the A/D conversion chip D2 are respectively connected with a clock circuit, and a resistor R1 is connected between a pin 49 and a pin 50 of the A/D conversion chip D2 in series.
4. A modem circuit based on GMSK technology according to claim 1, wherein: the D/A conversion circuit comprises an A/D conversion chip D3, a time relay JSZ31, a transmission transformer T1, a plurality of capacitors and a plurality of resistors, wherein the time relay JSZ31 is connected with the primary side of the transmission transformer T1, the secondary side of the transmission transformer T1 is connected with the A/D conversion chip D3, pins 90 and 91 of the A/D conversion chip D3 are respectively connected with a clock circuit, and a resistor R4 is connected between the pin 90 and the pin 91 of the A/D conversion chip D3 in series.
5. A modem circuit based on GMSK technology according to claim 1, wherein: the FPGA circuit comprises an FPGA chip D4, an input end pin of the FPGA chip D4 is respectively connected with an output end pin of the A/D conversion circuit and an output end pin of the clock circuit, an output end of the FPGA chip D4 is connected with an input end pin of the D/A conversion circuit, and an interface pin of the FPGA chip D4 is connected with the interface circuit.
6. A modem circuit based on GMSK technology according to claim 1, wherein: the power supply circuit comprises a three-terminal voltage regulator N3, voltage regulators N5-N8, a plurality of capacitors and a plurality of resistors, wherein the input end of the three-terminal voltage regulator N3 is connected with a commercial power supply, the output end of the three-terminal voltage regulator N3 outputs +5V and +3.3V voltages respectively, the input ends of the voltage regulators N5 and N7 are connected with the +3.3V voltage respectively, the output ends of the voltage regulators N5 and N7 are connected with an A/D conversion chip D2 power interface and an FPGA chip D4 power interface respectively, the input ends of the voltage regulators N6 and N8 are connected with the +5V voltage respectively, and the output ends of the voltage regulators N6 and N8 are connected with an A/D conversion chip D2 power interface and a power interface of.
7. A modem circuit based on GMSK technology according to claim 1, wherein: the clock circuit comprises a clock driver D13, a plurality of resistors, a plurality of capacitors, an amplifier D9, a transformer D11 and a clock oscillator Z1, wherein the input end of the amplifier D9 is connected with a bridge circuit formed by the capacitors and the resistors, the output end of the amplifier D9 is connected with the primary side of a transformer D11, pins 1 and 3 on the secondary side of the transformer D11 are respectively connected with pins 4 and 3 of the clock driver D13, pins 5 and 4 of the clock oscillator Z1 are respectively connected with pins 6 and 7 of the clock driver D13, pins 1, 9, 16, 25 and 32 of the clock driver D13 are connected with a power circuit after being short-circuited, pins 26 and 27 of the clock driver D13 are connected with an A/D conversion circuit, pins 30 and 31 of the clock driver D13 are respectively connected with the D/A conversion circuit, and pins 28 and 29 of the clock driver D13 are respectively connected with an FPGA chip.
8. A modem circuit based on GMSK technology according to claim 1, wherein: the interface circuit comprises a level conversion chip D15, a level conversion chip D16, a plurality of capacitors and a plurality of resistors, and the modem is respectively connected with the level conversion chips of the jump control unit and the communication unit through the level conversion chip D15 and the level conversion chip D16.
Technical Field
The invention relates to a modulation and demodulation circuit based on GMSK technology.
Background
GMSK modem technique: in GMSK modulation, a Gaussian low-pass pre-modulation filter is inserted before an MSK (minimum shift keying) modulator. The GMSK improves the frequency spectrum utilization rate and communication quality of digital mobile communication. It is characterized by that before the data stream is transferred into frequency modulator, a Gauss filter (preset filter) is used to make premodulation and filtering so as to reduce jump energy when the two carrier waves with different frequencies are switched, and make the channel spacing be more compact when the same data transmission rate is used. Because the digital signal is subjected to Gauss preset filtering processing before modulation, the signal spectrum of the modulated signal at the crossing zero point is compact, and the error code characteristic is good.
Disclosure of Invention
In order to solve the technical problem, the invention provides a modulation and demodulation circuit based on GMSK technology.
The invention is realized by the following technical scheme.
The invention provides a modulation and demodulation circuit based on GMSK technology, which comprises a conditioning circuit, an A/D conversion circuit, a D/A conversion circuit, an FPGA circuit, a power circuit, a clock circuit and an interface circuit, wherein the power circuit is respectively connected with the conditioning circuit, the A/D conversion circuit, the D/A conversion circuit and the FPGA circuit, the conditioning circuit is respectively connected with the A/D conversion circuit and the D/A conversion circuit, the A/D conversion circuit and the D/A conversion circuit are respectively connected with the clock circuit, the A/D conversion circuit, the D/A conversion circuit and the clock circuit are respectively connected with the FPGA circuit, and the FPGA circuit is connected with the interface circuit.
The conditioning circuit comprises a digital control variable gain amplifier D6, a digital control variable gain amplifier D7, a plurality of capacitors, a plurality of resistors, a time relay JSZ32, a time relay JSZ33, a transmission transformer T2 and a transmission transformer T4, wherein the time relay JSZ32 is connected with the input end of a transmission transformer T2, the output end of the transmission transformer T2 is connected with the input pin of a chip digital control variable gain amplifier D6, the 8 pin and the 9 pin of the chip digital control variable gain amplifier D6 are respectively connected with one end of a capacitor C281 and one end of a capacitor C280, the other end of the capacitor C281 is respectively connected with one end of a resistor R72 and one end of a resistor R76, the other end of the capacitor C280 is respectively connected with one end of a resistor R71 and one end of a resistor R75, the other end of a resistor R71 is in short circuit with the other end of the resistor R72, the other end of a resistor R75 and the other end of the resistor R76 are, a node between the resistor R71 and the resistor R72 is connected with the A/D conversion circuit, the node is connected with one end of the capacitor CH, and the other end of the capacitor CH is grounded;
the time relay JSZ33 is connected with the input end of a transmission transformer T4, the output end of a transmission transformer T4 is connected with the input pin of a chip digital control variable gain amplifier D7, the
The A/D conversion circuit comprises an A/D conversion chip D2, a plurality of resistors and a plurality of capacitors, wherein a
The D/A conversion circuit comprises an A/D conversion chip D3, a time relay JSZ31, a transmission transformer T1, a plurality of capacitors and a plurality of resistors, wherein the time relay JSZ31 is connected with the primary side of the transmission transformer T1, the secondary side of the transmission transformer T1 is connected with the A/D conversion chip D3,
The FPGA circuit comprises an FPGA chip D4, an input end pin of the FPGA chip D4 is respectively connected with an output end pin of the A/D conversion circuit and an output end pin of the clock circuit, an output end of the FPGA chip D4 is connected with an input end pin of the D/A conversion circuit, and an interface pin of the FPGA chip D4 is connected with the interface circuit.
The power supply circuit comprises a three-terminal voltage regulator N3, voltage regulators N5-N8, a plurality of capacitors and a plurality of resistors, wherein the input end of the three-terminal voltage regulator N3 is connected with a commercial power supply, the output end of the three-terminal voltage regulator N3 outputs +5V and +3.3V voltages respectively, the input ends of the voltage regulators N5 and N7 are connected with the +3.3V voltage respectively, the output ends of the voltage regulators N5 and N7 are connected with an A/D conversion chip D2 power interface and an FPGA chip D4 power interface respectively, the input ends of the voltage regulators N6 and N8 are connected with the +5V voltage respectively, and the output ends of the voltage regulators N6 and N8 are connected with an A/D conversion chip D2 power interface and a power interface of.
The clock circuit comprises a clock driver D13, a plurality of resistors, a plurality of capacitors, an amplifier D9, a transformer D11 and a clock oscillator Z1, wherein the input end of the amplifier D9 is connected with a bridge circuit formed by the capacitors and the resistors, the output end of the amplifier D9 is connected with the primary side of a transformer D11,
The interface circuit comprises a level conversion chip D15, a level conversion chip D16, a plurality of capacitors and a plurality of resistors, and the modem is respectively connected with the level conversion chips of the jump control unit and the communication unit through the level conversion chip D15 and the level conversion chip D16, so that the safe and stable transmission of signals among the units is facilitated.
The invention has the beneficial effects that: the modulation and demodulation processing of signals of a wireless communication system can be quickly realized, the detection of a peripheral electromagnetic environment can be realized, the technical maturity of a correlator composition circuit is high, the GMSK modulation mode is excellent in performance, and the method has a good application prospect.
Drawings
FIG. 1 is a schematic view of the module connection of the present invention;
FIG. 2 is a conditioning circuit of the present invention;
FIG. 3 is an A/D conversion circuit of the present invention;
FIG. 4 is a D/A conversion circuit of the present invention;
FIG. 5 is an FPGA circuit of the present invention;
FIG. 6 is a power supply circuit of the present invention;
FIG. 7 is a clock circuit of the present invention;
FIG. 8 is an interface circuit of the present invention;
fig. 9 is a working principle diagram of the present invention.
Detailed Description
The technical solution of the present invention is further described below, but the scope of the claimed invention is not limited to the described.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
A modulation and demodulation circuit based on GMSK technology comprises a conditioning circuit, an A/D conversion circuit, a D/A conversion circuit, an FPGA circuit, a power circuit, a clock circuit and an interface circuit, wherein the power circuit is respectively connected with the conditioning circuit, the A/D conversion circuit, the D/A conversion circuit and the FPGA circuit, the conditioning circuit is respectively connected with the A/D conversion circuit and the D/A conversion circuit, the A/D conversion circuit and the D/A conversion circuit are respectively connected with the clock circuit, the A/D conversion circuit, the D/A conversion circuit and the clock circuit are respectively connected with the FPGA circuit, and the FPGA circuit is connected with the interface circuit.
Preferably, the conditioning circuit comprises a digital control variable gain amplifier D6, a digital control variable gain amplifier D7, a plurality of capacitors, a plurality of resistors, a time relay JSZ32, a time relay JSZ33, a transmission transformer T2 and a transmission transformer T4, wherein the time relay JSZ32 is connected with the input end of the transmission transformer T2, the output end of the transmission transformer T2 is connected with the input pin of the chip digital control variable gain amplifier D6, the 8 pin and the 9 pin of the chip digital control variable gain amplifier D6 are respectively connected with one end of a capacitor C281 and one end of a capacitor C280, the other end of the capacitor C281 is respectively connected with one end of a resistor R72 and one end of a resistor R76, the other end of the capacitor C280 is respectively connected with one end of a resistor R71 and one end of a resistor R75, the other end of the resistor R71 is in short circuit with the other end of the resistor R72, the other end of a resistor R75 and the other end of the resistor R76 are, a node between the resistor R71 and the resistor R72 is connected with the A/D conversion circuit, the node is connected with one end of the capacitor CH, and the other end of the capacitor CH is grounded;
the time relay JSZ33 is connected with the input end of a transmission transformer T4, the output end of a transmission transformer T4 is connected with the input pin of a chip digital control variable gain amplifier D7, the
Preferably, the a/D conversion circuit includes an a/D conversion chip D2, a plurality of resistors, and a plurality of capacitors,
Preferably, the D/a conversion circuit comprises an a/D conversion chip D3, a time relay JSZ31, a transmission transformer T1, a plurality of capacitors and a plurality of resistors, the time relay JSZ31 is connected with the primary side of the transmission transformer T1, the secondary side of the transmission transformer T1 is connected with the a/D conversion chip D3,
Preferably, the FPGA circuit includes an FPGA chip D4, an input terminal pin of the FPGA chip D4 is respectively connected to an output terminal pin of the a/D conversion circuit and an output terminal pin of the clock circuit, an output terminal of the FPGA chip D4 is connected to an input terminal pin of the D/a conversion circuit, and an interface pin of the FPGA chip D4 is connected to the interface circuit.
Preferably, the power supply circuit comprises a three-terminal regulator N3, voltage regulators N5-N8, a plurality of capacitors and a plurality of resistors, wherein the input end of a three-terminal regulator N3 is connected with a commercial power supply, the output end of a three-terminal regulator N3 outputs +5V and +3.3V voltages respectively, the input ends of voltage regulators N5 and N7 are connected with the +3.3V voltage respectively, the output ends of voltage regulators N5 and N7 are connected with a power supply interface of an A/D conversion chip D2 and a power supply interface of an FPGA chip D4 respectively, the input ends of voltage regulators N6 and N8 are connected with the +5V voltage respectively, and the output ends of voltage regulators N6 and N8 are connected with a power supply interface of the A/D conversion chip D2 and a power.
Preferably, the clock circuit comprises a clock driver D13, a plurality of resistors, a plurality of capacitors, an amplifier D9, a transformer D11 and a clock oscillator Z1, wherein an input end of the amplifier D9 is connected with a bridge circuit formed by the capacitors and the resistors, an output end of the amplifier D9 is connected with a primary side of a transformer D11,
Preferably, the interface circuit comprises a level conversion chip D15, a level conversion chip D16, a plurality of capacitors and a plurality of resistors, and the modem is connected with the level conversion chips of the trip control unit and the communication unit through the level conversion chip D15 and the level conversion chip D16 respectively.
The circuit consists of five parts, namely a modulation part, a demodulation part, channel equalization, interference detection, interface communication and the like. The modulation part is completed by a conditioning DA circuit and an FPGA signal processing circuit, the demodulation part is completed by an AD circuit and an FPGA signal processing circuit, the channel equalization FPGA signal processing circuit is completed, the interference detection is completed by the AD circuit and the FPGA signal processing circuit, and the interface communication is completed by an interface circuit and the FPGA signal processing circuit.
The working principle of the modulation and demodulation unit composed of the modulation and demodulation circuit is shown in fig. 9, the modulation part is responsible for receiving information to be transmitted sent by the communication unit and the hopping control unit, performing operations such as grouping, encoding, interleaving, framing, baseband signal generation and the like, converting the information to a baseband signal modulated in a GMSK mode, generating an intermediate frequency modulation signal with a carrier frequency of 70MHz through digital up-conversion, and sending the intermediate frequency modulation signal to the channel unit to finish radio frequency transmission.
The demodulation part is responsible for removing carriers from 70MHz intermediate frequency modulation signals received by the channel unit, extracting baseband signals, then completing operations such as decoding, de-interleaving, data grouping and the like, and sending demodulated information to the communication unit and the hopping control unit.
The channel equalization is responsible for eliminating the influence of multipath on communication, multipath parameters of a wireless channel, including the number, the amplitude and the time delay of the multipath, are estimated by using a synchronization head of each frame of data, and then the influence of the multipath on a received wireless communication signal is eliminated.
The interference detection is responsible for monitoring the link condition of the wireless communication frequency band, scanning the frequency hopping channels one by one, judging whether interference exists by adopting an energy detection method, and giving the type and parameters of the interference by integrating multiple monitoring results.