Radar receiving and dispatching experiment system
阅读说明：本技术 一种雷达收发实验系统 (Radar receiving and dispatching experiment system ) 是由 张云飞 于 2020-06-30 设计创作，主要内容包括：本发明公开一种雷达收发实验系统,属于雷达实验教学技术领域,解决了现有技术中模拟雷达的功能不够齐全的技术问题。一种雷达收发实验系统,包括本振信号源模块、发射机模块及接收机模块,所述本振信号源模块、发射机模块及接收机模块之间相互连接,所述本振信号源模块,用于生成连续波信号或者脉冲波信号,以及生成第一本振源信号和第二本振源信号,并将所述连续波信号或者脉冲波信号以及第一本振源信号和第二本振源信号传送至所述发射机模块,并将第一本振源信号和第二本振源信号传送至接收机模块。本发明所述的雷达收发实验系统,可实现较为齐全的雷达功能模拟。(The invention discloses a radar transceiving experimental system, belongs to the technical field of radar experiment teaching, and solves the technical problem that functions of a simulation radar in the prior art are not complete enough. A radar receiving and dispatching experiment system comprises a local oscillator signal source module, a transmitter module and a receiver module which are connected with each other, wherein the local oscillator signal source module is used for generating a continuous wave signal or a pulse wave signal, generating a first local oscillation source signal and a second local oscillation source signal, transmitting the continuous wave signal or the pulse wave signal, the first local oscillation source signal and the second local oscillation source signal to the transmitter module, and transmitting the first local oscillation source signal and the second local oscillation source signal to the receiver module. The radar transceiving experimental system can realize relatively complete radar function simulation.)
1. A radar receiving and dispatching experiment system is characterized by comprising a local oscillator signal source module, a transmitter module and a receiver module, wherein the local oscillator signal source module, the transmitter module and the receiver module are electrically connected with one another;
the local oscillation signal source module is used for generating a continuous wave signal or a pulse wave signal, generating a first local oscillation source signal and a second local oscillation source signal, transmitting the continuous wave signal or the pulse wave signal, the first local oscillation source signal and the second local oscillation source signal to the transmitter module, and transmitting the first local oscillation source signal and the second local oscillation source signal to the receiver module;
the transmitter module is configured to filter the continuous wave signal or the pulse wave signal and adjust the intermediate frequency output power to obtain an adjusted signal, mix the adjusted signal with a first local oscillation source signal to obtain a first mixed signal, amplify and filter the first mixed signal, mix the amplified and filtered first mixed signal with a second local oscillation source signal, amplify and filter the amplified and filtered first mixed signal, and obtain a radar analog signal;
the receiver module is used for attenuating, amplifying and filtering the radar analog signal, mixing the attenuated, amplified and filtered radar analog signal with a second local vibration source signal to obtain a difference frequency signal, amplifying the difference frequency signal, then obtaining difference frequency with a first local vibration source signal to obtain an intermediate frequency signal, and carrying out logarithmic detection and IQ frequency mixing on the intermediate frequency signal.
2. The radar transceiving experimental system of claim 1, wherein the local oscillation signal source module comprises a radar signal source unit, a first local oscillation source unit, a second local oscillation source unit and a clock source unit;
the radar signal source unit comprises a DDS signal source chip U1, the DDS signal source chip U1 is used for generating continuous wave signals or pulse wave signals, and the continuous wave signals or the pulse wave signals are transmitted to the transmitter module through an IOUT2 pin of the DDS signal source chip;
the first local vibration source unit comprises a phase-locked loop chip U3, and the phase-locked loop chip U3 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the second local vibration source unit comprises a phase-locked loop chip U5, and the phase-locked loop chip U5 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the clock source unit is used for generating a clock source signal.
3. The radar transceiving experimental system of claim 2, wherein the transmitter module comprises an intermediate frequency conditioning and filtering unit, the continuous wave signal or the pulse wave signal is transmitted to the intermediate frequency conditioning and filtering unit, and the intermediate frequency conditioning and filtering unit comprises an LC filter circuit and a numerical control attenuator circuit;
the LC filter circuit comprises capacitors C1-C5, C17, inductors L2, L3 and L9, one end of the capacitor C1 is connected with one end of the inductor L2, the other end of the capacitor C1 is grounded, the other end of the inductor L2 is connected with one ends of the capacitors C2 and C4, the other end of the capacitor C2 is grounded, the other end of the capacitor C4 is connected with one end of the inductor L9, the other end of the inductor C9 is connected with one ends of the capacitors C5 and L1, the other end of the inductor L1 is grounded, the other end of the capacitor C5 is connected with the inductor L3, and the inductor L3 is connected with the capacitor C17;
the digital control attenuator circuit comprises a digital attenuator, and the digital attenuator is used for adjusting the intermediate frequency output power of the continuous wave signal or the pulse wave signal filtered by the LC filter circuit.
4. The radar transceiving experimental system of claim 3, wherein the transmitter module further comprises a first mixer unit, the first mixer unit is respectively connected to the intermediate frequency conditioning filter unit and the first local oscillation source unit, the first mixer unit comprises a mixer U10, capacitors C10, C20, C30, C40, C50, inductors L10, L20, and a diode D1, a GND pin of the mixer U11 is grounded, RF and IF pins of the mixer U10 are respectively connected to a capacitor C10 and a capacitor C20, the mixer U10 is grounded through a capacitor C30 and an inductor L10 and is connected to a cathode of the diode D1 through a capacitor C30, an anode of the diode D1 is respectively connected to one ends of a capacitor C40 and an inductor L20, and the other end of the inductor L20 is grounded through a capacitor C50.
5. The radar transceiving experimental system of claim 4, wherein the transmitter module further comprises a first intermediate frequency amplification filtering unit, the first intermediate frequency amplification filtering unit is connected to the first mixer unit, the first intermediate frequency amplification filtering unit comprises an amplifier A1, a capacitor C11, a capacitor C21, a capacitor C31, a capacitor C41, a capacitor C7, a resistor R1, a resistor R2, an inductor L11 and a resistor L21, an input of the amplifier A1 is connected to the capacitor C7, an output of the amplifier A1 is connected to one end of the inductor L11, another end of the inductor L11 is connected to one end of the capacitor C41, another end of the capacitor C41 is connected to one end of the capacitor C31, a series-connected end of the resistors R1 and R2 is connected to the other end of the C31 and one end of the inductor L21, and another series-connected inductor of the resistors R1 and R2 is connected to the other end of the inductor L11; the other end of the inductor L21 is grounded through a capacitor C11, and the capacitor C21 is connected in parallel with the capacitor C11.
6. The experimental system for radar transmission/reception, according to claim 5, wherein the transmitter module further includes a second mixer unit and a first high-frequency amplifying and filtering unit, the second mixer unit has the same circuit structure as the first mixer unit, the second mixer unit is respectively connected to the first intermediate-frequency amplifying and filtering unit and the second local oscillator unit, the first high-frequency amplifying and filtering unit is connected to the second local oscillator unit, and the first high-frequency amplifying and filtering unit includes amplifiers a12 and a22, capacitors C12, C22, C32, C42, C72, C92, C102, resistors R12, R22, R72, R82, inductors L12, L22, L32, and L42;
the input end of the amplifier A12 is connected with a capacitor C72, the output end of the amplifier A12 is connected with one end of an inductor L12, the other end of the inductor L12 is connected with one end of a capacitor C42, the other end of the capacitor C42 is connected with one end of a capacitor C32, one end of resistors R12 and R22 which are connected in series is connected with the other end of the inductor C32 and one end of the inductor L32, and the other end of the resistors R12 and R22 which are connected in series is connected with the other end of the inductor L12; the other end of the inductor L32 is grounded through a capacitor C12, and the capacitor C21 is connected with a capacitor C12 in parallel;
the input end of the amplifier A22 is the output end of an amplifier A12, the output end of the amplifier A12 is connected with one end of an inductor L22, the other end of the inductor L22 is connected with one end of a capacitor C102, the other end of the capacitor C102 is connected with one end of a capacitor C92, one end of resistors R72 and R82 which are connected in series is connected with the other end of the inductor C92 and one end of an inductor L42, and the other end of the resistors R72 and R82 which are connected in series is connected with the other end of the inductor L22; the other end of the inductor L42 is grounded through a capacitor C12.
7. The radar transmission/reception experiment system according to claim 6, wherein the receiver module includes an analog attenuator unit and a second high-frequency amplification filtering unit, and the second high-frequency amplification filtering unit has the same circuit structure as the first high-frequency amplification filtering unit; the analog attenuator unit comprises digital attenuators U13 and U23, an RFin pin of the digital attenuator U13 is connected with the first high-frequency amplification filtering unit, an RFout pin of the digital attenuator U13 is connected with an RFin pin of the digital attenuator U23, and a TFout pin of the digital attenuator U23 is connected with the second high-frequency amplification filtering unit.
8. The radar transceiving experimental system of claim 7, wherein the receiver module further comprises an STC unit, a first mixer unit, a second mixer unit, a first if amplifying and filtering unit, and a second if amplifying and filtering unit, and the first mixer unit, the second mixer unit, and the first if amplifying and filtering unit of the receiver module are respectively the same as the first mixer unit, the second mixer unit, and the first if amplifying and filtering unit of the transmitter module;
the STC unit comprises a fixed attenuator and a variable attenuator and is used for dynamically attenuating the output signal of the second high-frequency amplifying and filtering unit, the output signal of the STC unit is mixed with the second local oscillation source signal through the first mixer unit, and then the difference frequency signal is obtained by the first intermediate frequency amplifying and filtering unit, then the second mixer unit mixes the frequency with the first local oscillation source signal to obtain a signal after secondary frequency mixing, the signal after secondary frequency mixing is transmitted to the second intermediate frequency amplifying and filtering unit, the second IF amplifying and filtering unit comprises amplifiers A14 and A24 and an attenuator U14, the input end of the amplifier A14 is connected with the signal after secondary mixing, the output end of the amplifier A14 is connected with the RFin pin of the attenuator U14, the RFout pin of the attenuator U14 is connected with the input end of an amplifier A24, and the second intermediate frequency amplifying and filtering unit outputs two intermediate frequency signals.
9. The radar transceiving experimental system of claim 8, wherein the receiver module further comprises a detector unit, the detector unit comprises a logarithmic amplifier U4, an operational amplifier U29A and an operational amplifier U29GB, an input of the logarithmic amplifier U4 is connected to an output end of the second if amplifying and filtering unit, an output of the logarithmic amplifier U4 is connected to positive input ends of the operational amplifier U29A and the operational amplifier U29B, negative input ends of the operational amplifier U29A and the operational amplifier U29B are grounded, and the operational amplifier U29B outputs the detected signal.
10. The radar transceiving experimental system of claim 9, wherein the receiver module further comprises an IQ mixing unit, the IQ mixing unit comprises a 90 ° phase-shifting power divider, a mixer, a video amplifier and a filter, the clock source signal is transformed into an orthogonal clock source signal through the 90 ° phase-shifting power divider, and the two intermediate frequency signals output by the second intermediate frequency amplifying and filtering unit are respectively mixed with the two orthogonal clock source signals by the mixer, filtered by the filter and amplified by the video amplifier.
Technical Field
The invention relates to the technical field of radar experiment teaching, in particular to a radar transceiving experiment system.
Background
The existing radar teaching system is usually divided into a radar receiver and a radar receiver by a system splitting device, so that the purchase price is relatively high, and the internal circuit structure of the system is not developed outwards, so that principle teaching is not deep enough, and besides, the signal waveform of the radar teaching system on the market is single, and the radar teaching system lacks functions of sensitivity time gain control, space loss simulation, detection, moving target detection and the like, and can only simulate partial types of radars and has insufficient functions of simulating radars.
Disclosure of Invention
In view of this, the invention provides a radar transceiving experimental system, which solves the technical problem that the functions of the analog radar in the prior art are not complete enough.
The invention provides a radar transceiving experimental system which comprises a local oscillation signal source module, a transmitter module and a receiver module, wherein the local oscillation signal source module, the transmitter module and the receiver module are electrically connected with one another;
the local oscillation signal source module is used for generating a continuous wave signal or a pulse wave signal, generating a first local oscillation source signal and a second local oscillation source signal, transmitting the continuous wave signal or the pulse wave signal, the first local oscillation source signal and the second local oscillation source signal to the transmitter module, and transmitting the first local oscillation source signal and the second local oscillation source signal to the receiver module;
the transmitter module is configured to filter the continuous wave signal or the pulse wave signal and adjust the intermediate frequency output power to obtain an adjusted signal, mix the adjusted signal with a first local oscillation source signal to obtain a first mixed signal, amplify and filter the first mixed signal, mix the amplified and filtered first mixed signal with a second local oscillation source signal, amplify and filter the amplified and filtered first mixed signal, and obtain a radar analog signal;
the receiver module is used for attenuating, amplifying and filtering the radar analog signal, mixing the attenuated, amplified and filtered radar analog signal with a second local vibration source signal to obtain a difference frequency signal, amplifying the difference frequency signal, then obtaining difference frequency with a first local vibration source signal to obtain an intermediate frequency signal, and carrying out logarithmic detection and IQ frequency mixing on the intermediate frequency signal.
Furthermore, the local oscillation signal source module comprises a radar signal source unit, a first local oscillation source unit, a second local oscillation source unit and a clock source unit;
the radar signal source unit comprises a DDS signal source chip U1, the DDS signal source chip U1 is used for generating continuous wave signals or pulse wave signals, and the continuous wave signals or the pulse wave signals are transmitted to the transmitter module through an IOUT2 pin of the DDS signal source chip;
the first local vibration source unit comprises a phase-locked loop chip U3, and the phase-locked loop chip U3 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the second local vibration source unit comprises a phase-locked loop chip U5, and the phase-locked loop chip U5 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the clock source unit is used for generating a clock source signal.
Further, the transmitter module comprises an intermediate frequency conditioning and filtering unit, the continuous wave signal or the pulse wave signal is transmitted to the intermediate frequency conditioning and filtering unit, and the intermediate frequency conditioning and filtering unit comprises an LC filtering circuit and a numerical control attenuator circuit;
the LC filter circuit comprises capacitors C1-C5, C17, inductors L2, L3 and L9, one end of the capacitor C1 is connected with one end of the inductor L2, the other end of the capacitor C1 is grounded, the other end of the inductor L2 is connected with one ends of the capacitors C2 and C4, the other end of the capacitor C2 is grounded, the other end of the capacitor C4 is connected with one end of the inductor L9, the other end of the inductor C9 is connected with one ends of the capacitors C5 and L1, the other end of the inductor L1 is grounded, the other end of the capacitor C5 is connected with the inductor L3, and the inductor L3 is connected with the capacitor C17;
the digital control attenuator circuit comprises a digital attenuator, and the digital attenuator is used for adjusting the intermediate frequency output power of the continuous wave signal or the pulse wave signal filtered by the LC filter circuit.
Further, the transmitter module further includes a first mixer unit, the first mixer unit is respectively connected to the intermediate frequency conditioning filter unit and the first local oscillation source unit, the first mixer unit includes a mixer U10, a capacitor C10, a capacitor C20, a C30, a C40, a C50, an inductor L10, an L20, and a diode D1, a GND pin of the mixer U11 is grounded, RF and IF pins of the mixer U10 are respectively connected to the capacitor C10 and the capacitor C20, the mixer U10 is grounded through the capacitor C30 and the inductor L10 and is connected to a cathode of the diode D1 through the C30, an anode of the diode D1 is respectively connected to one end of the capacitor C40 and the inductor L20, and the other end of the inductor L20 is grounded through a capacitor C50.
Further, the transmitter module further includes a first intermediate frequency amplification filtering unit, the first intermediate frequency amplification filtering unit is connected with the first mixer unit, the first intermediate frequency amplification filtering unit includes an amplifier a1, a capacitor C11, C21, C31, C41, C7, a resistor R1, R2, an inductor L11, and an inductor L21, an input of the amplifier a1 is connected with the capacitor C7, an output of the amplifier a1 is connected with one end of the inductor L11, the other end of the inductor L11 is connected with one end of the capacitor C41, the other end of the capacitor C41 is connected with one end of the capacitor C31, a serial end of the resistors R1 and R2 is connected with the other end of the C31 and one end of the inductor L21, and the serial end of the resistors R1 and R2 is connected with the other end of the inductor L11; the other end of the inductor L21 is grounded through a capacitor C11, and the capacitor C21 is connected in parallel with the capacitor C11.
Further, the transmitter module further includes a second mixer unit and a first high-frequency amplifying and filtering unit, the second mixer unit has the same circuit structure as the first mixer unit, the second mixer unit is respectively connected to the first intermediate-frequency amplifying and filtering unit and the second local oscillation source unit, the first high-frequency amplifying and filtering unit is connected to the second local oscillation source unit, and the first high-frequency amplifying and filtering unit includes amplifiers a12 and a22, capacitors C12, C22, C32, C42, C72, C92, C102, resistors R12, R22, R72, R82, inductors L12, L22, L32, and L42;
the input end of the amplifier A12 is connected with a capacitor C72, the output end of the amplifier A12 is connected with one end of an inductor L12, the other end of the inductor L12 is connected with one end of a capacitor C42, the other end of the capacitor C42 is connected with one end of a capacitor C32, one end of resistors R12 and R22 which are connected in series is connected with the other end of the inductor C32 and one end of the inductor L32, and the other end of the resistors R12 and R22 which are connected in series is connected with the other end of the inductor L12; the other end of the inductor L32 is grounded through a capacitor C12, and the capacitor C21 is connected with a capacitor C12 in parallel;
the input end of the amplifier A22 is the output end of an amplifier A12, the output end of the amplifier A12 is connected with one end of an inductor L22, the other end of the inductor L22 is connected with one end of a capacitor C102, the other end of the capacitor C102 is connected with one end of a capacitor C92, one end of resistors R72 and R82 which are connected in series is connected with the other end of the inductor C92 and one end of an inductor L42, and the other end of the resistors R72 and R82 which are connected in series is connected with the other end of the inductor L22; the other end of the inductor L42 is grounded through a capacitor C12.
Furthermore, the receiver module comprises an analog attenuator unit and a second high-frequency amplification filtering unit, and the circuit structure of the second high-frequency amplification filtering unit is the same as that of the first high-frequency amplification filtering unit; the analog attenuator unit comprises digital attenuators U13 and U23, an RFin pin of the digital attenuator U13 is connected with the first high-frequency amplification filtering unit, an RFout pin of the digital attenuator U13 is connected with an RFin pin of the digital attenuator U23, and a TFout pin of the digital attenuator U23 is connected with the second high-frequency amplification filtering unit.
Furthermore, the receiver module further includes an STC unit, a first mixer unit, a second mixer unit, a first intermediate frequency amplification filtering unit, and a second intermediate frequency amplification filtering unit, where the first mixer unit, the second mixer unit, and the first intermediate frequency amplification filtering unit of the receiver module are respectively the same as the first mixer unit, the second mixer unit, and the first intermediate frequency amplification filtering unit of the transmitter module;
the STC unit comprises a fixed attenuator and a variable attenuator and is used for dynamically attenuating the output signal of the second high-frequency amplifying and filtering unit, the output signal of the STC unit is mixed with the second local oscillation source signal through the first mixer unit, and then the difference frequency signal is obtained by the first intermediate frequency amplifying and filtering unit, then the second mixer unit mixes the frequency with the first local oscillation source signal to obtain a signal after secondary frequency mixing, the signal after secondary frequency mixing is transmitted to the second intermediate frequency amplifying and filtering unit, the second IF amplifying and filtering unit comprises amplifiers A14 and A24 and an attenuator U14, the input end of the amplifier A14 is connected with the signal after secondary mixing, the output end of the amplifier A14 is connected with the RFin pin of the attenuator U14, the RFout pin of the attenuator U14 is connected with the input end of an amplifier A24, and the second intermediate frequency amplifying and filtering unit outputs two intermediate frequency signals.
Further, the receiver module further includes a detection unit, the detection unit includes a logarithmic amplifier U4, an operational amplifier U29A and an operational amplifier U29GB, an input end of the logarithmic amplifier U4 is connected to an output end of the second intermediate frequency amplification filtering unit, an output end of the logarithmic amplifier U4 is connected to positive input ends of the operational amplifier U29A and the operational amplifier U29B, negative input ends of the operational amplifier U29A and the operational amplifier U29B are grounded, and the operational amplifier U29B outputs a signal after detection.
Furthermore, the receiver module further includes an IQ mixing unit, where the IQ mixing unit includes a 90 ° phase-shift power divider, a mixer, a video amplifier, and a filter, the clock source signal is converted into an orthogonal clock source signal by the 90 ° phase-shift power divider, and two intermediate frequency signals output by the second intermediate frequency amplification filtering unit are respectively mixed with two orthogonal clock source signals by the mixer, filtered by the filter, and amplified by the video amplifier;
compared with the prior art, the invention has the beneficial effects that: generating a continuous wave signal or a pulse wave signal and generating a first local vibration source signal and a second local vibration source signal through a local vibration signal source module, transmitting the continuous wave signal or the pulse wave signal and the first local vibration source signal and the second local vibration source signal to the transmitter module, and transmitting the first local vibration source signal and the second local vibration source signal to a receiver module; the transmitter module is used for filtering the continuous wave signal or the pulse wave signal and adjusting the intermediate frequency output power to obtain an adjusted signal, mixing the adjusted signal with a first local oscillation source signal to obtain a first mixing signal, amplifying and filtering the first mixing signal, and mixing, amplifying and filtering the amplified and filtered first mixing signal and a second local oscillation source signal to obtain a radar analog signal; the receiver module is used for attenuating, amplifying and filtering the radar analog signal, mixing the attenuated, amplified and filtered radar analog signal with a second local vibration source signal to obtain a difference frequency signal, amplifying the difference frequency signal, then obtaining difference frequency with a first local vibration source signal to obtain an intermediate frequency signal, and carrying out logarithmic detection and IQ frequency mixing on the intermediate frequency signal; can realize the simulation of more complete radar functions.
Drawings
Fig. 1 is a schematic structural diagram of a radar transceiving experimental system according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a detailed structure of a radar transceiving experimental system according to an embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of a radar signal source unit according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a first local oscillator unit according to an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a second local oscillator unit according to an embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a clock source unit according to an embodiment of the present invention;
FIG. 7 is a circuit schematic of an external interface unit according to an embodiment of the present invention;
fig. 8 is a schematic circuit diagram of an if conditioning filter unit according to an embodiment of the present invention;
fig. 9 is a schematic circuit diagram of a first mixer unit according to an embodiment of the invention;
fig. 10 is a schematic circuit diagram of a first if amplifying and filtering unit according to an embodiment of the present invention;
fig. 11 is a schematic circuit diagram of a first high-frequency amplification filtering unit according to an embodiment of the present invention;
FIG. 12 is a circuit schematic of an analog attenuator cell according to an embodiment of the present invention;
fig. 13 is a schematic illustration of a static STC curve according to an embodiment of the present invention;
FIG. 14 is a schematic circuit diagram of a second IF amplifying and filtering unit according to an embodiment of the present invention
FIG. 15 is a schematic circuit diagram of a detector unit according to an embodiment of the invention;
fig. 16 is a schematic circuit diagram of an IQ mixer according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment of the invention provides a radar transceiving experimental system, which has a schematic structural diagram as shown in fig. 1 and comprises a local oscillator signal source module, a transmitter module and a receiver module, wherein the local oscillator signal source module, the transmitter module and the receiver module are electrically connected with each other;
the local oscillation
the
the
In a specific embodiment, as shown in fig. 2, IFin, IF1in, RFin, etc. are represented as input terminals, IFout, IF1out, RFout, etc. are represented as output terminals, where TX mixing one represents a first mixer unit, an IF amplifying and filtering one represents a first IF amplifying and filtering unit, TX mixing two represents a second mixer unit, and so on;
preferably, the local oscillation signal source module comprises a radar signal source unit, a first local oscillation source unit, a second local oscillation source unit and a clock source unit;
the radar signal source unit comprises a DDS signal source chip U1, the DDS signal source chip U1 is used for generating continuous wave signals or pulse wave signals, and the continuous wave signals or the pulse wave signals are transmitted to the transmitter module through an IOUT2 pin of the DDS signal source chip;
the first local vibration source unit comprises a phase-locked loop chip U3, and the phase-locked loop chip U3 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the second local vibration source unit comprises a phase-locked loop chip U5, and the phase-locked loop chip U5 is used for generating a first local vibration source signal and sending the first local vibration source signal to the transmitter module and the receiver module through an RFoutA + pin of the phase-locked loop chip U3;
the clock source unit is used for generating a clock source signal;
in a specific embodiment, the circuit schematic diagrams of the radar signal source unit, the first local oscillation source unit, the second local oscillation source unit and the clock source unit are respectively shown in fig. 3 to 6, and the radar transceiving experimental system further includes an external interface unit, the circuit schematic diagram of which is shown in fig. 7; the DDS signal source chip is of an AD9854 model, the phase-locked loop chip is of an ADF4351 model, the crystal oscillator in the figure is a 30MHz crystal oscillator, an STM32F103 can be used as a main control chip, the AD9854 can be controlled by controlling the positions 0x1F of a register from Mode0 to Mode2 to generate continuous waves (Mode 000) or pulse waves (Mode 011), the ACC2 of 0x1F is controlled by matching with an STM32 timer to generate pulse signals with the frequency of 100Hz to 1KHz and the pulse width of 1 to 500us, the frequency tuning word 1 and the
preferably, the transmitter module includes an intermediate frequency conditioning and filtering unit, the continuous wave signal or the pulse wave signal is transmitted to the intermediate frequency conditioning and filtering unit, and the intermediate frequency conditioning and filtering unit includes an LC filter circuit and a numerical control attenuator circuit;
the LC filter circuit comprises capacitors C1-C5, C17, inductors L2, L3 and L9, one end of the capacitor C1 is connected with one end of the inductor L2, the other end of the capacitor C1 is grounded, the other end of the inductor L2 is connected with one ends of the capacitors C2 and C4, the other end of the capacitor C2 is grounded, the other end of the capacitor C4 is connected with one end of the inductor L9, the other end of the inductor C9 is connected with one ends of the capacitors C5 and L1, the other end of the inductor L1 is grounded, the other end of the capacitor C5 is connected with the inductor L3, and the inductor L3 is connected with the capacitor C17; the digital attenuator circuit comprises a digital attenuator, and the digital attenuator is used for adjusting the intermediate frequency output power of the continuous wave signal or the pulse wave signal filtered by the LC filter circuit;
in a specific embodiment, as shown in fig. 8, in a schematic circuit diagram of the intermediate frequency conditioning and filtering unit, a radar signal source signal is filtered by the intermediate frequency conditioning and filtering unit, and is output after power adjustment; the intermediate frequency conditioning and filtering unit comprises an LC filtering circuit and a numerical control attenuator circuit, a band-pass filter in the intermediate frequency conditioning and filtering unit is used for suppressing signals such as harmonic waves and clutter and optimizing the quality of the signals, and the digital attenuator circuit can adjust the intermediate frequency output power and finally adjust the transmitting power; adjusting the range by 15dB and stepping by 1 dB;
preferably, the transmitter module further includes a first mixer unit, the first mixer unit is respectively connected to the intermediate frequency conditioning filter unit and the first local oscillation source unit, the first mixer unit includes a mixer U10, a capacitor C10, a capacitor C20, a C30, a C40, a C50, an inductor L10, an L20, and a diode D1, a GND pin of the mixer U11 is grounded, RF and IF pins of the mixer U10 are respectively connected to the capacitor C10 and the capacitor C20, the mixer U10 is grounded via the capacitor C30 and the inductor L10 and is connected to a cathode of the diode D1 via the C30, an anode of the diode D1 is respectively connected to one end of the capacitor C40 and the inductor L20, and the other end of the inductor L20 is grounded via a capacitor C50;
in a specific embodiment, as shown in fig. 9, the circuit schematic diagram of the first mixer unit mixes TX frequency, the first mixer unit mixes the conditioned and filtered signal with the first local oscillation source signal, and takes the difference frequency signal, so as to ensure the signal power requirement, the first intermediate frequency amplifying and filtering unit amplifies and filters the mixed signal;
preferably, the transmitter module further includes a first intermediate frequency amplification filtering unit, the first intermediate frequency amplification filtering unit is connected to the first mixer unit, the first intermediate frequency amplification filtering unit includes an amplifier a1, a capacitor C11, C21, C31, C41, C7, a resistor R1, R2, an inductor L11, and an inductor L21, an input of the amplifier a1 is connected to the capacitor C7, an output of the amplifier a1 is connected to one end of the inductor L11, another end of the inductor L11 is connected to one end of the capacitor C41, another end of the capacitor C41 is connected to one end of the capacitor C31, a serial end of the resistors R1 and R2 is connected to the other end of the capacitor L31 and one end of the inductor L21, and another serial end of the resistors R1 and R2 is connected to the other end of the inductor L11; the other end of the inductor L21 is grounded through a capacitor C11, and the capacitor C21 is connected with a capacitor C11 in parallel;
in a specific embodiment, as shown in fig. 10, the first intermediate frequency amplification filtering unit includes two intermediate frequency surface acoustic wave filters and an amplifier, a single filter suppresses out-of-band by 40dB, the performance of the first intermediate frequency amplification filtering unit is reflected in a system image suppression index, and meanwhile, the filter needs to suppress a local oscillator leakage signal;
preferably, the transmitter module further includes a second mixer unit and a first high-frequency amplifying and filtering unit, the second mixer unit has the same circuit structure as the first mixer unit, the second mixer unit is respectively connected to the first intermediate-frequency amplifying and filtering unit and the second local oscillation source unit, the first high-frequency amplifying and filtering unit is connected to the second local oscillation source unit, and the first high-frequency amplifying and filtering unit includes amplifiers a12 and a22, capacitors C12, C22, C32, C42, C72, C92, C102, resistors R12, R22, R72, R82, inductors L12, L22, L32, and L42;
the input end of the amplifier A12 is connected with a capacitor C72, the output end of the amplifier A12 is connected with one end of an inductor L12, the other end of the inductor L12 is connected with one end of a capacitor C42, the other end of the capacitor C42 is connected with one end of a capacitor C32, one end of resistors R12 and R22 which are connected in series is connected with the other end of the inductor C32 and one end of the inductor L32, and the other end of the resistors R12 and R22 which are connected in series is connected with the other end of the inductor L12; the other end of the inductor L32 is grounded through a capacitor C12, and the capacitor C21 is connected with a capacitor C12 in parallel;
the input end of the amplifier A22 is the output end of an amplifier A12, the output end of the amplifier A12 is connected with one end of an inductor L22, the other end of the inductor L22 is connected with one end of a capacitor C102, the other end of the capacitor C102 is connected with one end of a capacitor C92, one end of resistors R72 and R82 which are connected in series is connected with the other end of the inductor C92 and one end of an inductor L42, and the other end of the resistors R72 and R82 which are connected in series is connected with the other end of the inductor L22; the other end of the inductor L42 is grounded through a capacitor C12.
In a specific embodiment, the signal frequency after the first mixing and filtering is about 505MHz, the second mixer unit mixes the intermediate frequency signal 505MHz with the second local oscillation source signal, and then the first high-frequency amplifying and filtering unit obtains the difference frequency signal (1200MHz to 1400 MHz);
a schematic circuit diagram of the first high-frequency amplification filtering unit is shown in fig. 11, the first high-frequency amplification filtering unit mainly comprises two amplifiers and a filter, the filter is realized by adopting a dielectric filter, the filter mainly inhibits signals such as local oscillator leakage signals, out-of-band spurious signals, harmonic waves and the like, the first high-frequency amplification filtering unit realizes high-power signal amplification in a real radar, generally hundreds of watts, upper kilowatts and the like, the first high-frequency amplification filtering unit is used for teaching a laboratory principle, the analog transmission power is 0.1W, and the cascade amplifier improves the module gain;
preferably, the receiver module includes an analog attenuator unit and a second high-frequency amplification filtering unit, and the circuit structure of the second high-frequency amplification filtering unit is the same as that of the first high-frequency amplification filtering unit; the analog attenuator unit comprises digital attenuators U13 and U23, an RFin pin of the digital attenuator U13 is connected with the first high-frequency amplification filtering unit, an RFout pin of the digital attenuator U13 is connected with an RFin pin of the digital attenuator U23, and a TFout pin of the digital attenuator U23 is connected with the second high-frequency amplification filtering unit.
In a specific embodiment, the schematic circuit diagram of the analog attenuator unit is, as shown in fig. 12, a built-in fixed attenuator and a variable attenuator are used in series, and the attenuation module simulates loss of a radar signal during spatial transmission, according to a transmission distance formula:
LbS＝32.45+20lgF(MHz)+20lgD(km)
the device can simulate a 60dB dynamic attenuation range and can simulate an attenuation range between 0.1Km and 100Km, and signals are amplified and filtered by a second high-frequency amplification filtering unit after the space loss is simulated by the simulated attenuation module;
the second high-frequency amplifying and filtering unit has the same circuit structure as the first high-frequency amplifying and filtering unit and consists of a low-noise amplifier and a dielectric filter; the amplified and filtered signals are dynamically attenuated by an STC unit, so that the overload of an intermediate frequency amplifier caused by short-range clutter interference is prevented;
preferably, the receiver module further includes an STC unit, a first mixer unit, a second mixer unit, a first intermediate frequency amplification filtering unit, and a second intermediate frequency amplification filtering unit, where the first mixer unit, the second mixer unit, and the first intermediate frequency amplification filtering unit of the receiver module are respectively the same as the first mixer unit, the second mixer unit, and the first intermediate frequency amplification filtering unit of the transmitter module;
the STC unit comprises a fixed attenuator and a variable attenuator and is used for dynamically attenuating the output signal of the second high-frequency amplifying and filtering unit, the output signal of the STC unit is mixed with the second local oscillation source signal through the first mixer unit, and then the difference frequency signal is obtained by the first intermediate frequency amplifying and filtering unit, then the second mixer unit mixes the frequency with the first local oscillation source signal to obtain a signal after secondary frequency mixing, the signal after secondary frequency mixing is transmitted to the second intermediate frequency amplifying and filtering unit, the second IF amplifying and filtering unit comprises amplifiers A14 and A24 and an attenuator U14, the input end of the amplifier A14 is connected with the signal after secondary mixing, the output end of the amplifier A14 is connected with the RFin pin of the attenuator U14, the RFout pin of the attenuator U14 is connected with the input end of an amplifier A24, and the second intermediate frequency amplifying and filtering unit outputs two intermediate frequency signals.
In a specific embodiment, the STC module circuit is the same as the analog attenuation circuit, and mainly comprises a fixed attenuator and a variable attenuator, and this embodiment uses a static STC, that is, a set of static STC curves is preset according to the relationship between the spatial attenuation and the transmission distance, and the schematic diagram of the static STC curves is shown in fig. 13;
the signal after the adjustment of the filtering power is mixed with two local vibration sources (signals) through a first mixing unit, and then a difference frequency signal is obtained through a first intermediate frequency amplifying and filtering unit, so that the purpose of down-conversion is achieved;
the central frequency of the filter of the first intermediate frequency amplifying and filtering unit is 535 MHz; after the difference frequency signal is amplified, the difference frequency signal is mixed with a local vibration source to obtain a difference frequency, and then a 30MHz intermediate frequency signal can be obtained;
as shown in fig. 14, the second intermediate frequency amplifying and filtering unit includes a built-in filter, an amplifier, a power divider, a digital attenuator, and other components; the digital attenuator is used for amplifying echo signals and inhibiting local oscillation signals, and is used for adjusting system gain and increasing the receiving dynamic range of a receiver; the second intermediate frequency amplifying and filtering unit filters the sum frequency signal of the second mixer unit to obtain a difference frequency signal, and the power divider is used for dividing the signal into two paths of signals with equal frequency and power, wherein one path of signals is used for logarithmic detection, and the other path of signals is used for IQ frequency mixing;
preferably, the transmitter module further includes a detector unit, the detector unit includes a logarithmic amplifier U4, an operational amplifier U29A and an operational amplifier U29GB, an input end of the logarithmic amplifier U4 is connected to an output end of the second intermediate frequency amplification filtering unit, an output end of the logarithmic amplifier U4 is connected to positive input ends of the operational amplifier U29A and the operational amplifier U29B, negative input ends of the operational amplifier U29A and the operational amplifier U29B are grounded, and the operational amplifier U29B outputs a signal after detection.
In a specific embodiment, a schematic circuit diagram of the detection unit is shown in fig. 15, the detection unit mainly comprises a logarithmic amplifier (AD8310) and an operational amplifier, the AD8310 is a high-speed voltage output type logarithmic amplifier which can demodulate the frequency range from DC to 440MHz, because the carrier frequency of the radar transmission pulse is very high, it is difficult to directly measure parameters such as pulse width, pulse repetition frequency, duty ratio and the like, a microwave detector is usually used for detecting the radar transmission signal, and the carrier frequency is filtered to obtain the radar transmission signal envelope;
preferably, the transmitter module further includes an IQ mixing unit, where the IQ mixing unit includes a 90 ° phase-shift power divider, a mixer, a video amplifier, and a filter, the clock source signal is converted into an orthogonal clock source signal by the 90 ° phase-shift power divider, and two intermediate frequency signals output by the second intermediate frequency amplification and filtering unit are respectively mixed with two orthogonal clock source signals by the mixer, filtered by the filter, and amplified by the video amplifier;
in a specific embodiment, the IQ mixer unit is a schematic circuit diagram, and as shown in fig. 16, the IQ mixer unit includes a 90 ° phase-shifting power divider SCPQ-50, mixers U123 and U121, a video amplifier LMV358IDT, and a filter; an intermediate frequency output signal of the receiver is input through J4 and divided into two paths of signals by a power divider, a clock source signal is input through J3 and converted into two orthogonal paths of clock source signals by a 90-degree phase-shifting power divider, the two paths of intermediate frequency signals are respectively mixed with the two orthogonal paths of clock source signals, filtered and amplified, namely, an orthogonal I, Q-channel orthogonal detector is adopted for detecting; the frequency of the detected signal is the Doppler frequency shift; according to the doppler shift formula:
wherein, VRIs the moving speed of the target, C is the propagation speed of the electromagnetic wave in the space, f0For the radar wave transmission frequency, fdIs a Doppler shift; passing letterThe frequency shift quantity of the signal can calculate the motion speed of the object, and the IQ frequency mixing module can be used for simulating moving target detection;
it should be noted that, in the above figures, the SMA is an input terminal or an output terminal of a signal, and it should be understood by those skilled in the art that the element parameters, such as the resistance value of the resistor, can be set and adjusted by those skilled in the art according to actual needs.
The invention discloses a radar receiving and transmitting experimental system, which generates a continuous wave signal or a pulse wave signal and a first local vibration source signal and a second local vibration source signal through a local vibration signal source module, transmits the continuous wave signal or the pulse wave signal and the first local vibration source signal and the second local vibration source signal to a transmitter module, and transmits the first local vibration source signal and the second local vibration source signal to a receiver module; the transmitter module is used for filtering the continuous wave signal or the pulse wave signal and adjusting the intermediate frequency output power to obtain an adjusted signal, mixing the adjusted signal with a first local oscillation source signal to obtain a first mixing signal, amplifying and filtering the first mixing signal, and mixing, amplifying and filtering the amplified and filtered first mixing signal and a second local oscillation source signal to obtain a radar analog signal; the receiver module is used for attenuating, amplifying and filtering the radar analog signal, mixing the attenuated, amplified and filtered radar analog signal with a second local vibration source signal to obtain a difference frequency signal, amplifying the difference frequency signal, then obtaining difference frequency with a first local vibration source signal to obtain an intermediate frequency signal, and carrying out logarithmic detection and IQ frequency mixing on the intermediate frequency signal; can realize the more complete radar function simulation; the radar sensor can simulate various radar signal waveforms, and has the functions of sensitivity time gain control, space loss simulation, detection, moving target detection and the like;
the technical scheme of the invention combines the radar transmitter and the radar receiver into a whole to reduce the cost, and in addition, the invention also modularizes a hardware circuit, has a standard input/output interface, and can plug and pull the module; the customization cost is reduced, and the maintenance is convenient; each module and unit in the invention can use transparent acrylic plate as cover; can see through the apron direct observation circuit structure, make things convenient for principle teaching greatly.
The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.
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