SU1444676A1 - Device for measuring carrier frequency of single microwave pulses - Google Patents

Abstract

The invention relates to a radio measuring technique, namely, to means of measuring the carrier frequency of single pulses of the microwave wavelength range. The purpose of the invention is to expand the frequency range in the high frequency region while maintaining measurement accuracy. The device solves the problem of measuring the carrier frequency of a single microwave pulse in a wide frequency band (13-18 GHz). This is ensured by using, instead of an acoustic delay line with a piezoelectric transducer, a superconducting recirculator and inserting into the device circuit of valve 1, limiter 2 of the power level of the microwave impulse under investigation, directional 7 junction, unit 6 of generating the key control pulse. In addition, the device contains converters 4 single microwave pulse in a series of radio pulses, amplifier 9, detector 10, directional coupler 3 and the counter 11 of the number of pulses. With the help of a recirculator, pre-calibrated on pulses with a known frequency, consisting of a superconducting delay line 8 and a control key 5, a single microwave pulse t with an unknown carrier frequency is converted into a series of microwave pulses that, after amplification and detection; fixed by the indicator. From the calibration data and the number of pulses in a series, the unknown frequency of the SEC pulse is determined. By using the superconducting delay line 8, in addition to achieving the main objective, the sensitivity of the device is increased. 2 Il. Q (Л с 4 4: 4 05 а. F

Description

The invention relates to radio metering technology and can be used in radar systems for HSMepe and carrier frequencies of single microwave pulses,

The aim of the invention is to spread the frequency range to higher frequencies while maintaining measurement accuracy.

Fig. 1 is a block diagram of a device for measuring the carrier frequency of a single microwave pulse; Fig. 2 shows the diagrams showing the operation of the device.

A device for measuring the carrier frequency of a single microwave pulse contains a-fan 1, a limiter 2 of the power level of the SACh pulse, a directional coupler 3, a converter 4 of a single microwave pulse into a series of radio pulses, including a control key 6, a pulse shaping unit 6 control, directional coupler 7 and superconducting dispersionless delay line 8.

The device also contains an amplifier 9, a detector 10, a pulse number counter 11. Valve 1 is connected via the limiter 2 of the microwave pulse to the first input of the directional coupler 3, the output of the main line of which is connected to the input of the control key 5, which is also the first input of the transducer 4 of the single microwave pulse to the radio pulse series.

The second output of the directional coupler 3 is connected to the input of the control pulse generation unit 6, this input being the second one; converter input. The output of the key 5 is connected to the input of the second directional coupler .7, the first output of which is connected to the input of the superconducting (coaxial) delay line 8, short-circuited at the opposite end. The second output of the coupler 7 is connected to the input of the amplifier 9, the output of which through the microwave detector 10 is connected to the input of the counter 11 of the number of pulses. The input of the device is the input of the valve 1.

The device for measuring the carrier frequency of a single microwave pulse operates as follows.

In the calibration mode, which is carried out using a highly stable tunable microwave gene

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Rotor, a calibration microwave pulse of a given duration with a known carrier frequency fo is fed to the input of the device. Passing the ferrite valve 1, the calibration pulse is limited in limiter 2 to the I level Uj, in amplitude and passes to the directional coupler 3. Part of the power of the calibration pulse determined by the transient attenuation of the directional coupler, from the second output of the directional coupler 3 goes to the second input of the converter the initiator 4, the start-up control key block 5. The output impulse of control block 6 sets the key 5 to the Open state for a time equal to Lo + t, where t J is the delay time of the part of the microwave path connecting blocks 3 and 5. Cali rovochny pulse passes through the open switch 5 and the directional coupler 7 in superconducting Ko rotkozamknutuyu at the end of the delay line 8. After that, the key 5 returns to the initial state Closed, and the calibration pulse, reflected from the short-circuited end of the delay line 8, returns to its beginning, which is connected to the key 5. The key 5 in the Closed state is practically a short circuit of the microwave signal. therefore, the microwave pulse, reflected from this short circuit, is returned again to the superconducting delay line 8, As a result of the calibration of the microwave pulse through the delay line 8, a series of radio pulses is formed at the second output of the directional coupler 7. After amplification in amplifier 9 and detection by detector 10 with recording equipment 11, a series of video pulses with an exponential envelope is detected. For a known carrier frequency, the number of pulses in a series is entered into correspondence. Further, the frequency of the calibration microwave generator is changed and the number of pulses in a series, limited in advance by a given level of amplitude attenuation, is recorded again. As a result of the calibration, a calibration dependence is constructed that relates the carrier frequency and the number of recorded video pulses.

In the measurement mode, a single microwave pulse arriving at the device input with an unknown carrier frequency, passing through gate 1, limits 3 u

with amplitude limiter 2 to a predetermined level U ,, and through directional coupler 3 is fed to the first input of converter 4 of a single pulse into a series of SV-radio pulses, which is the input of a control key 5, which is closed in its initial state, i.e. . It is practically a short circuit in the microwave path. Part of the input signal through the auxiliary line of the directional coupler 3 is fed to the second input of the converter 4, i.e. to the input of the control pulse shaping unit 6; key 5. At the output of the control unit, a SI1-voltage is produced, and the key 5 is in the Open state. The lengths of the signal path between blocks 3, 5 and 3, 6, 5 are chosen such that they ensure the input pulse through the opened key 5 and the main line of the directional coupler 7 to the superconducting short-circuited coaxial line 8 delay. Key 5 is in the Open state for a time determined by the duration of the input microwave pulse, at the end of which the key returns to its initial state Closed. The impulse under study, arriving at the coaxial delay line 8, reaches its closed end and is reflected, returning to the line input and key output 5. Here again there is a reflection from the low input resistance of key 5 in the opposite direction. As a result, if the length of the delay line 8 is such that the double travel time of the pulse under investigation exceeds its duration, at the auxiliary output of the directional coupler 7 we have a series of radio pulses, illustrated by the vertical lines in Fig. 2, the use of the directional 7 coupler in the converter allows select a small part of the energy of the pulse circulating in the delay line 8, which is diverted by the auxiliary line of the coupler 7 to the input of the amplifier 9. After amplification, the signal under study is given and the input of the detector 10, where it is released) envelope. The amplitude of the envelopes of the microwave pulses decreases with an increase in their number according to an exponential law with an exponent proportional to

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the attenuation of the pulse energy during a double run along the delay line at a given frequency. A change in the carrier frequency of the microwave pulse leads to a change in the exponential law for quenching, and consequently, to a change in the number of pulses received in a series. The carrier frequency of the studied microwave pulse is determined from the calibration dependence between the frequency of the microwave pulse previously known and the number of recorded video pulses.

Consider the operation of the meter when measuring the carrier frequency, which is, for example, 10 Gy, for a microwave pulse with a duration of 50 - 100 ns. Calibration of the meter is performed prior to measurement.

Calibration is carried out as follows.

Using a high-speed switch (modulator), included in the external path of a highly stable tunable microwave generator of the desired range, for example, 9 - 12 GHz, a calibration pulse with a duration of 50 ns is formed. A calibration pulse with a duration of, for example, 50 NS with a known GHz carrier frequency is fed to the input of the meter. Pass the ferrite valve 1, the calibration pulse is limited in limiter 2 to the level Uo in amplitude and passes to the directional coupler 3. Part of the power of the calibration pulse of the second output of the directional coupler 3 is fed to the second input of the converter 4, starting up the key control unit 6 5. Output pulse control unit 6 switches key 5 to the Open state for time (50 not + t), where t, j is the delay time of the part of the path connecting blocks 3 and 5, the calibration pulse passes through the public key 5 and the directional coupler 7 to the superconducting short-delay line 8 at the end. After this, the key 5 returns to the initial state Closed, and the calibration pulse circulates in the superconducting line with double delay time Tz 1 ISS (5 ns / mx x2 2s100 m 1 μs), where 5 ns / m is the passage time of the microwave pulse meter of superconducting cable. With each cycle, from the second output of the directional coupler 7, a portion of the power of the calibration pulse is relegated to the amplifier 9. Next, these pulses are detected by the SECH detector 10 and in a series of damped video pulses with a period of 1 µs are fed to the counter 11, which registers the number of pulses until the amplitude of one of them will decrease to a predetermined level and,. Thus, given the pulse duration with a known frequency, the number of pulses of a series formed during the circulation of the calibration pulse in the superconducting delay line 8 is entered. Repeating the calibration operation for different values of the tunable microwave frequency, we obtain the dependence; carrier frequency - the number of video pulses in a series. This relationship is used as a gauge.

After calibrating the meter, the process of measuring the unknown frequency of a single microwave pulse is performed.

A SSCH pulse with an unknown carrier frequency is applied to the input of the meter. Further, the process is similar to what happened during calibration. As a result of repeated passage of the pulse under investigation over the superconducting delay line 6, a series of microwave pulses are formed at the auxiliary output of the directional response 7, the envelopes of which are picked up with the detector 10, and the number of video pulses is fixed by the counter 11. The count data of these pulses is calibration dependence, we determine the nonsure frequency of the pulse under study.

The use of a superconducting coaxial delay line in the device makes it possible to extend the range of measured frequencies up to 18 GHz. The liquid line operating in this gel is characterized by a high degree of wave impedance regularity, a frequency bandwidth of 0 ~ 18 GHz, and a attenuation of 0.45 dB / km at GHz, which translates into a delay time of 0.09 dB / µs. The microwave pulse level limiter introduced into the device, the first and second directional couplers and the key practically do not add in addition

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This restriction is on the frequency range of the device.

Introduction to the device limiter amplitude of the pulse. allows you to simplify the measurement process, reducing it to counting the number of pulses in a series resulting from the circulation of the material under study.

The use of a superconducting delay line allows measurement of the carrier frequencies of single microwave pulses up to 15 GHz using a single bee line to change the design of the device and its bulkhead. The only requirement is to comply with the conditions: Tz,. where 2 is the pulse duration, Tz is the double delay time of the superconducting delay line 8. For the given example, with a length of the superconducting delay line 8 of length 100 m (µs), the carrier frequency of the microwave pulses with a duration from a few nanoseconds to 1 microsecond can be measured. To extend the range of durations of the measured pulses, a longer delay line should be taken.

F o rm ula invention

Claims (2)

1. Device for measuring the carrier frequency of a single microwave pulse, containing a converter of a single microwave pulse into a series of radio pulses, an amplifier, a detector and a pulse number counter, in series, in order to expand the range of measured frequencies, are additionally introduced in series connected valve, power limiter of the EHF pulse and directional coupler, the first output of which is connected to the first input of the converter, and the second output - to the second input of the conversion bodies of a single microwave pulse in a series of radio pulses, the output of which is connected to the input of the amplifier. 2. The device according to claim. otli Since the converter of a single microwave pulse into a series of radio pulses contains a series-connected control pulse shaping unit, a controllable key, the second input of which is 7 U446768 The first input of the converter is the second control pulse, the second directional coupler and the superconductor input of the converter, the second output of the nondispersive line of the directional responder is the holder, the input of the converter output formation unit. Ulb "u uo Compiled by Yu.Minkin. Editor N.Gorvat Tekhred L.Oliynyk Order 6501/43 Circulation 772 VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab.luD. 4/5 ipia.Z Proofreader G. Reshetnik Subscription