RU37236U1 - PASSIVE TRANSMITTER - Google Patents

Description

The invention relates to radar and is intended to transmit identification signals and identification of radar surveillance objects. It can be used in air traffic control systems, in remote object identification systems and in other areas.

Known passive transceiver, which by technical nature is closest to the claimed (see RF patent No. 2174239, IPC GO IS 13/74), selected as a prototype of the invention. The prototype device comprises an antenna connected to a combined input - output of the modulator, a decisive device and an identification code generator connected in series, connected by a group of outputs to a group of modulator inputs, a power supply connected by a first output to a second input of an identification code generator, and a second output to a first decision input devices, and detector.

The request signal from the interrogator (active radar) is received by the antenna and fed to the modulator. Part of the request signal passes through the modulator to the detector. The detector selects the envelope of the request signal, which from the output of the detector enters the first input of the decisive

devices. The second input of the deciding device is supplied with voltage from the second output of the power source. The solver compares the envelope voltage of the request signal with a threshold and, based on it, generates control signals for the identification code generator. The control signals from the output of the deciding device are fed to the first input of the identification code generator, to the second input of which a voltage is supplied from the first output of the power source. The code generator contains a memory for storing identification information and when it receives control signals at its first input, it turns on and generates an identification code. The code contains data on frequency additions for generating a response signal at a carrier frequency other than the frequency of the interrogation signal. The identification code from the group of outputs of the code generator goes to the group of inputs of the modulator. Simultaneously with the identification code, a request signal is supplied to the input-output of the modulator. Under the action of the identification code, the modulator changes the phase of the request signal according to a stepwise-linear law so that it acquires a frequency addition and is converted into a response signal. The modulator returns the response signal back to the antenna. The antenna emits a response signal towards the interrogator (active radar).

The conditions typical for the operation of passive transceivers of identification and recognition systems are characterized by a wide range of changes in the amplitudes of the interrogation signals and the effect of interference on the transceiver. The change in the amplitudes of the request signals is due to

moving the observation object and (or) the radar in space, as well as scanning the radiation pattern of the radar antenna. The interference is the result of reflections of the interrogation signals from the elements of the surface of the passive transceiver and the work of the transmitting stations. They create spurious amplitude modulation of the interrogation signals. For these reasons, the signals at the input of the modulator turn out to be fluctuating in amplitude.

The amplitude of the output signal of the modulator depends on its state. In the absence of an identification code (logical zeros) on the group of inputs of the modulator, the latter is in the off state (all p-i-n diodes are off) and the transmittance of the request signal by it is close to unity. As a result, the signal at the detector input is maximum and the detector operates in a linear mode. When an identification code (logical units) arrives at a group of modulator inputs, its p-i-n diodes turn on and off sequentially and the amplitude of the request signal transmitted to the detector decreases (the transmittance of the modulator is less than unity). The result of quadratic detection is a decrease, in comparison with the linear mode, of the signal-to-noise ratio at the detector output (see Vollerner NP Radio receivers. - K .: Vishka shkola, 1993, p. 203-217).

Thus, the use of a passive type detector in a known transceiver reduces the noise immunity

3. the transceiver during the formation of the response signal by the modulator, which

is a disadvantage of the prototype device.

The problem to which the invention is directed is to increase the noise immunity, ish, and frequency of the passive transceiver by suppressing spurious amplitude modulation of the interrogation signal and maintaining the level of the input signal of the solver within the required limits.

The dryness of the present invention lies in the fact that the passive transceiver contains an antenna connected to a combined input / output of the modulator, connected in series, its device and identification code generator, connected by a group of outputs to a group of inputs of a modulator, a power source, connected by the first output to the second input of the identification code generator, and the second output to the first input of the resolving device, the detector, an amplifier with high-speed automatic adjustment power (BARU) and amplitude limiter, while the first input of the amplifier with BARU is connected to the output of the modulator, and the output to the input of the detector, the output of which is connected to the first input of the amplitude limiter, the output of which is connected to the second input of the deciding device, and the second output of the power source connected to the second inputs of the amplifier with a BAR and an amplitude limiter.

4

A passive transceiver also contains, like the prototype, an antenna 1 connected to a combined input-output of a modulator 2, a solver 3 and an identification code generator 4 connected in a series of outputs to a group of inputs of a modulator 2, a power supply 5 connected by a first output to a second the input of the identification code generator 4, and the second output, to the first input of the resolving device 3, and detector 6. In contrast to the prototype, an amplifier 7 with high-speed automatic devices was introduced into the passive transceiver gain control (BARU) and amplitude limiter 8, while the first input of amplifier 7 with BARU is connected to the output of modulator 2, and the output to the input of detector 6, the output of which is connected to the first input of amplitude limiter 8, the output of which is connected to the second input of the decisive devices 3. The second output of the power source 5 is connected to the second inputs of the amplifier 7 with BAR and amplitude limiter 8.

Antenna 1 is, for example, a microstrip transceiver antenna. The modulator 2 is made according to the scheme, for example, p-i-n diode reflective phase shifter on a microstrip transmission line. The output of the modulator 2 is connected by a microstrip transmission line to the first input of the amplifier 7 with a BAR, the output of which is connected to the input of the diode pulse detector 6. The output of the detector 6 is connected to the first input of the amplitude limiter 8, the output of which is connected to the second input of the resolving device 3. Device and principle of operation amplifier

7 with BARU are described in the book (Vollerner NP Radio-reception devices. K .: Vishka school, 1993, p. 243), diode pulse detector 6 - in the same source of information, p. 199-201, amplitude limiter 8 - in the same source of information, pp.213-215. An amplifier 7 with a BARU, an amplitude limiter 8, and a resolving device 3 is supplied through a power source 5. For example, batteries are used as a power source 5 in a passive transceiver. The solver 3 is, for example, a single-threshold integrated comparator. Identification code generator 4 is made in the same way as in the prototype and is, for example, a digital machine with memory.

Passive transceiver operates as follows.

The request signal from the interrogator (active radar) received by the antenna 1 is fed to the input-output of the modulator 2. A part of the request signal passes through the modulator 2 to the input of the amplifier 7 with the BAR. For this reason, regardless of the state of the p-i-n diodes of the modulator 2 and the fluctuation of the interrogation signal, the signal amplitude at the output of the amplifier 7 is maintained within the limits necessary for the normal functioning of subsequent devices. From the output of amplifier 7, a request signal is input to detector 6. Detector 6 extracts the envelope of the request signal and transfers it to the input of amplitude limiter 8. Amplitude limiter 8 suppresses stray amplitude modulation of pulse signals. From its output, the pulse signals are fed to the second input of the resolver 3. In the resolver 3, the amplitudes of the pulse signals

are compared with threshold voltage. In case of exceeding the threshold, I decide the device 3 generates a signal (impulse) to control the identification code generator 4, i.e. is transferred from a logical zero state to a logical unit state in its output for the duration of the request signal T. The state of the logical unit at the output of the resolver 3 is stored until the digital code exceeds the threshold. Upon receipt from the output of the deciding device 3 to the first input of the code generator 4 a control signal of duration T, it turns on and sequentially generates at its N outputs KN disjoint pulses with an amplitude of a logical unit and a duration A, where K 1,2,3 ... is an integer , and T KNAr. The number of bGST pulses and their duration A characterize the identification code of code generator 4. The identification code from the group of outputs of code generator 4 is fed to the group of inputs of modulator 2. At the same time as the identification code, a request signal is input to the input-output of modulator 2. Under the action of the identification code, the modulator 2 changes the phase of the request signal according to a stepwise-linear law so that it acquires a frequency additive and is converted into a response signal. Modulator 2 returns the response signal back to antenna 1, which emits a response signal to the interrogator (active radar). The presence at known times of a response signal with a known frequency

additive can be considered as the transfer of units in the discharge of a discrete message, and its absence is equivalent to the transfer of zero.

Achievable technical result from the use of the present invention is to increase the noise immunity of a passive transceiver by suppressing spurious amplitude modulation of the interrogation signal and maintaining the level of the input signal of the deciding device within the required limits.

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Claims (1)

A passive transceiver comprising an antenna connected to a combined modulator input-output, a decoupling device and an identification code generator connected in series by a group of outputs to a group of modulator inputs, a power source connected by a first output to a second input of an identification code generator, and a second output to a first input of a decoding device , a detector, characterized in that an amplifier with high-speed automatic gain control (BAR) and an amp limiter are inserted into it Ituda, the first input of the amplifier from the BAR is connected to the output of the modulator, and the output to the input of the detector, the output of which is connected to the first input of the amplitude limiter, the output of which is connected to the second input of the resolver, and the second output of the power source is connected to the second inputs of the amplifier with BAR and amplitude limiter.