CN210405301U

CN210405301U - Frequency hopping control circuit of unmanned aerial vehicle short wave radio station

Info

Publication number: CN210405301U
Application number: CN202020319741.7U
Authority: CN
Inventors: 许鸣; 黄婷
Original assignee: Nanjing Maimiao Electronic Technology Co Ltd; Nanjing Wanzilian Electronic Technology Co Ltd
Current assignee: Nanjing Maiyiqin Electronic Technology Co.,Ltd.; Nanjing wanzilian Electronic Technology Co.,Ltd.
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-04-24
Anticipated expiration: 2030-03-16

Abstract

The utility model discloses a frequency hopping control circuit of an unmanned aerial vehicle short-wave radio station, which comprises a microprocessor, a power conditioning circuit, a voltage acquisition circuit, a frequency hopping setting circuit and a communication circuit, wherein the power conditioning circuit, the voltage acquisition circuit, the frequency hopping setting circuit and the communication circuit are respectively electrically connected with the microprocessor; the frequency hopping setting circuit comprises a DDS chip integrated with an ADC and a filtering feedback circuit, and the voltage acquisition circuit comprises a voltage division circuit, a plurality of operational amplifiers and a linear optocoupler. The utility model adopts the DDS chip to be applied in the frequency hopping setting circuit, and has the advantages of fast switching speed of frequency hopping frequency points, high frequency resolution, good phase noise performance and the like; the microprocessor generates a signal with specified frequency according to the received frequency hopping control command transmitted by the control center, and simultaneously reflects the voltage quantity to the data center in real time. The design of the circuit considers the problem of circuit interference, and effective isolation is realized through a linear optical coupler.

Description

Frequency hopping control circuit of unmanned aerial vehicle short wave radio station

Technical Field

The utility model relates to a radio communication field and electricity field, specifically speaking relate to a frequency hopping control circuit of unmanned aerial vehicle short wave radio station.

Background

The short-wave radio station has simpler equipment and can carry out long-distance communication with lower power, thereby playing an important role in military communication; however, short-wave communication capacity is small, a propagation channel is unstable, and transmission reliability is low.

The frequency hopping communication makes the original fixed radio transmitting frequency jump back and forth according to a certain rule and speed, and the appointed opposite side synchronously tracks and receives according to the rule. Since the third party does not know the hopping rule of the radio signal, the information is difficult to intercept.

The frequency synthesizer is a key part in a frequency hopping communication system, and currently, a phase-locked loop (PLL) frequency synthesis technology is adopted in most frequency hopping radio stations, but the frequency conversion speed of the technology is close to the limit, and the use effect is poor.

Disclosure of Invention

The purpose of the invention is as follows: the utility model aims at providing a frequency hopping control circuit of unmanned aerial vehicle short wave radio station based on DDS chip founds.

The technical scheme is as follows: the utility model discloses a frequency hopping control circuit of an unmanned aerial vehicle short-wave radio station, which comprises a microprocessor, a power conditioning circuit, a voltage acquisition circuit, a frequency hopping setting circuit and a communication circuit, wherein the power conditioning circuit, the voltage acquisition circuit, the frequency hopping setting circuit and the communication circuit are respectively electrically connected with the microprocessor; the frequency hopping setting circuit comprises an AD9912 chip and a filtering feedback circuit, wherein the AD9912 chip is provided with a serial communication interface and an external clock signal interface which are connected with the micro-processing system; the voltage acquisition circuit comprises a voltage division circuit, a plurality of operational amplifiers and a linear optical coupler.

The microprocessor is an STM32F103R8T6 chip. The clock frequency of the chip can reach 72MHz at most, 64K Flash, 20K RAM, 12 bit AD, 4 16 bit timers, 3 paths of USART communication ports and other resources are arranged in the chip, and the chip has extremely high cost performance. The chip is mainly used for data acquisition and processing, communication with a control center, control of setting of frequency hopping sequences and the like.

The voltage acquisition circuit is an acquisition circuit of 24V voltage of a system power supply battery and is used for giving early warning in time when the voltage of the system battery is undervoltage. Including bleeder circuit, first operational amplifier, linear opto-coupler and the second operational amplifier who connects gradually, the output pin of second operational amplifier is connected to microprocessor STM32F103R8T6 chip. Further, the first operational amplifier and the second operational amplifier are of LM2904 type; the linear optocoupler is of an HCNR200 model and is used for ensuring that circuits on two sides of the optocoupler are not interfered with each other; the linear optical coupler is an analog signal isolation device with excellent cost performance, and has the characteristics of low nonlinearity, typical value of 0.1%, optimal value of 0.01%, low temperature coefficient, wide frequency band high precision and the like.

The power conditioning circuit comprises a VRB2403S-6WR3 power module for converting into 3.3V voltage, and the input end of the power conditioning module is connected with 24V voltage. The VRB2403S-6WR3 power supply module is a 6W wide voltage input isolation voltage stabilization DC/DC power supply module, the efficiency is up to 87%, and the working temperature range is-40 to +105 ℃.

The communication circuit is used for transmitting the collected voltage quantity to the control center and receiving control commands (including frequency hopping control commands) of the control center. The utility model provides a communication circuit chooses for use MAX3232 chip. The transceiver of the MAX3232 chip adopts a special low-voltage difference transmitter output stage, the true RS-232 performance can be realized by using a double-charge pump when a power supply of 3.0V to 5.5V is used for supplying power, and the device only needs four external small-size charge pump capacitors of 0.1 uF. The MAX3232 chip ensures a data rate of 120kbps while maintaining the RS-232 output level.

Thereby frequency hopping setting circuit's effect produce the signal that corresponds the frequency point through SPI bus receiving microprocessor system's order, realize that signal frequency jumps according to established rule. The AD9912 chip is a digital synthesizer (DDS) chip, and is characterized by integrating a 14-bit digital-to-analog converter (DAC), having a frequency control word (FTW) with 48 bits and being capable of realizing the frequency resolution of 4 mu Hz. The frequency absolute accuracy is obtained by adjusting the DAC system clock. The AD9912 chip also provides an integrated system clock Phase Locked Loop (PLL) that allows the system clock input to be as low as 25 mhz. The AD9912 can operate in the industrial temperature range of minus 40 ℃ to plus 85 ℃.

The AD9912 chip is connected with the microprocessor system through serial control ports SDIO, SDO and SCLK, a chip selection pin CSB and a data updating control pin IO _ UPDATE, receives and executes a command of modifying a chip register of the microprocessor, and finishes generation of a specified frequency signal.

And a DAC pin of the AD9912 chip is sequentially connected with the first radio frequency transformer module, the filtering feedback circuit, the second radio frequency transformer module and an FDBK pin of the AD9912 chip. The first radio frequency transformer module and the second radio frequency transformer module are TC2-1 TX +, the transformer has good return loss, excellent amplitude imbalance (0.5 dB typ) and phase imbalance (4 deg. typ), and the working temperature range is-45-80 ℃. The filter feedback circuit is at least provided with 11 capacitors and 3 inductors which are connected in series-parallel.

Has the advantages that: the DDS chip is applied to the frequency hopping setting circuit, has the advantages of high frequency hopping frequency point switching speed, high frequency resolution, good phase noise performance and the like, and has more advantages than phase-locked loop frequency synthesis; the microprocessor generates a signal with specified frequency according to the received frequency hopping control command transmitted by the control center, and simultaneously reflects the voltage quantity to the data center in real time. The design of the circuit considers the problem of circuit interference, and effective isolation is realized through a linear optical coupler.

Drawings

FIG. 1 is a schematic circuit configuration diagram of embodiment 1;

FIG. 2 is a schematic pin diagram of a microprocessor according to embodiment 1;

FIG. 3 is a circuit diagram of a power supply conditioning circuit in embodiment 1;

FIG. 4 is a circuit diagram of a 24V voltage acquisition circuit in embodiment 1;

fig. 5 is a circuit diagram of an RS232 communication circuit in embodiment 1;

fig. 6 is a circuit diagram of a frequency hopping setting circuit in embodiment 1.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

Example 1

As shown in figure 1, a frequency hopping control circuit of unmanned aerial vehicle short wave radio station, including microprocessor system, respectively with microprocessor electric connection's power conditioning circuit, voltage acquisition circuit, frequency hopping setting circuit and RS232 communication circuit, microprocessor sends the voltage quantity signal data of gathering to control center through communication circuit to the state of suggestion system battery electric quantity, receives control center's command control frequency hopping setting circuit through communication circuit simultaneously, thereby accomplishes the control of frequency hopping sequence.

As shown in fig. 2, the microprocessor of this embodiment is an STM32F103R8T6 type chip based on an ARM Cortex processor core, the clock frequency of the chip can reach 72MHz at most, 64K Flash, 20K RAM, 12 bit AD, 4 16 bit timers, 3 channels of USART communication ports and other resources are built in, and the cost performance is very high. The chip is mainly used for data acquisition and processing, communication with a control center and the like.

As shown in FIG. 3, the power conditioning circuit comprises a transformation circuit which is based on a VRB2403S-6WR3 DC/DC power module and converts 24V into 3.3V voltage of a microprocessor, pin No. 2 and pin No. 1 of the VRB2403S-6WR3 are respectively connected to 24V power and ground of a 24V battery of the system through an inductor L8, and pin No. 3 and pin No. 5 output 3.3V and ground respectively to supply power to the whole circuit.

As shown in fig. 4, the voltage acquisition circuit includes a plurality of LM2904 operational amplifiers and HCNR200 linear optocouplers. The collected voltage is divided and then enters a pin No. 2 of a first operational amplifier LM2904, an amplified signal is output from a pin No. 1 of the first operational amplifier LM2904 and is connected to a linear optical coupler HCNR200, the optical coupler output is connected to a pin No. 2 of a second operational amplifier LM2904, and an isolated signal is amplified and then output from a pin No. 1 of the second operational amplifier LM2904 and is connected to an AD _ U of an STM32F103R8T6 chip.

As shown in FIG. 5, the communication circuit includes an RS232 communication module connected to the STM32F103R8T6 chip. The communication module selects MAX3232 type chips. The No. 9 pin and the No. 10 pin of the MAX3232 chip are respectively connected with a serial port receiving pin PA3 and a serial port sending pin PA2 of the STM32F103R8T6 chip; no. 7 pin and No. 8 pin of the MAX3232 chip are respectively connected to a sending pin and a receiving pin of the RS232 bus, meanwhile, a capacitor of 0.1uF is respectively bridged between No. 1 pin and No. 3 pin of the MAX3232 chip and between No. 15 pin and No. 16 pin, and the No. 2 pin and the No. 6 pin are respectively connected with a capacitor of 0.1uF to the ground.

As shown IN fig. 6, the frequency hopping setting circuit includes a DDS-based AD9912 chip, which is connected to an STM32F103R8T6 chip, SCLK, SDIO, SDO, CSB, and IO _ UPDATE pins of the AD9912 chip are connected to PB13, PB15, PB14, PB12, and PB11 pins of the STM32F103R8T6 chip, respectively, to form a channel for serial communication between them,

pins

27 and 28 of the AD9912 chip are connected to an external clock signal of 50M,

pins

50 and 51 are a DAC output (DAC _ OUT) and a complementary DAC output (DAC _ OUTB),

pins

41 and 40 are a feedback input (FDBK _ IN) and a complementary feedback input (FDBK _ INB), and DAC output signals are filtered and fed back to the input terminal through a filter circuit FC1 formed by capacitors and inductors between the first rf transformer module T1/second rf transformer module T2 and the two. The filter circuit is composed of capacitors C74, C77, C81, C83, C75, C78, C82, C84, C73, C80 and C76 and inductors L10, L9 and L11, wherein one ends of the first 8 capacitors are all grounded, one ends of C74, C73, L9 and C75 are connected together to be an input end of the filter (DAC output signals after passing through a first radio frequency transformer module T1 enter the filter from here), the other end of C73 is connected to one ends of C77, L10, C76, C78 and L9, the other end of L10 is connected to one ends of C81, C80, L11, C82 and C76, the other end of C80 is connected to one ends of C83, C84 and L11 to be an output end of the filter, and the DAC output signals are transmitted to feedback input (FDBK _ INBK) and FDBK (FDBK) of T9912 through T2.

Claims

1. The utility model provides a frequency hopping control circuit of unmanned aerial vehicle short wave radio station which characterized in that: the frequency hopping circuit comprises a microprocessor, a power supply conditioning circuit, a voltage acquisition circuit, a frequency hopping setting circuit and a communication circuit, wherein the power supply conditioning circuit, the voltage acquisition circuit, the frequency hopping setting circuit and the communication circuit are respectively electrically connected with the microprocessor; the frequency hopping setting circuit comprises an AD9912 chip and a filtering feedback circuit, wherein the AD9912 chip is provided with a serial communication interface and an external clock signal interface which are connected with the micro-processing system; the voltage acquisition circuit comprises a voltage division circuit, a plurality of operational amplifiers and a linear optical coupler.

2. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 1, characterized in that: the microprocessor is an STM32F103R8T6 chip.

3. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 2, characterized in that: the voltage acquisition circuit includes bleeder circuit, first operational amplifier, linear opto-coupler and the second operational amplifier that connects gradually, the output pin of second operational amplifier is connected to STM32F103R8T6 chip.

4. The frequency hopping control circuit of the unmanned aerial vehicle short-wave radio station of claim 3, characterized in that: the first operational amplifier and the second operational amplifier are LM2904 type.

5. The frequency hopping control circuit of the unmanned aerial vehicle short-wave radio station of claim 3, characterized in that: the linear optocoupler is of an HCNR200 model.

6. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 2, characterized in that: the power conditioning circuit comprises a VRB2403S-6WR3 power module for converting into 3.3V voltage, and the input end of the power conditioning module is connected with 24V voltage.

7. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 2, characterized in that: the communication circuit is a MAX3232 chip.

8. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 1, characterized in that: and a DAC pin of the AD9912 chip of the frequency hopping setting circuit is sequentially connected with the first radio frequency transformer module, the filtering feedback circuit, the second radio frequency transformer module and an FDBK pin of the AD9912 chip.

9. The frequency hopping control circuit of the short wave radio station of the unmanned aerial vehicle of claim 1, characterized in that: the filter feedback circuit is at least provided with 11 capacitors and 3 inductors which are connected in series-parallel.