RU82042U1 - DEVICE FOR MEASURING SIGNAL PARAMETERS OF A MODULE OF A LINEAR-FREQUENCY-MODULATED FILTER - Google Patents

Abstract

1. A device for measuring signal parameters of a linear-frequency-modulated filter module, comprising a pulse shaper, a key and a controlled generator, characterized in that it contains a control voltage generator, a high frequency generator, a first video amplifier, a tee, a first radio frequency amplifier, a first adapter, a linear module a frequency-modulated filter, a second radio frequency amplifier, an amplitude detector, a second video amplifier and an oscilloscope, the first output of a pulse shaper connected to the input of the key , the key output is connected to the first input of the control voltage generator, the second output of the pulse generator is connected to the second input of the control voltage generator, the output of the control voltage generator is connected to the first input of the controlled generator, the output of the high-frequency generator is connected to the second input of the controlled generator, the third output of the pulse shaper is connected with the input of the first video amplifier, the output of the first video amplifier is connected to the third input of a controlled generator, the output of a controlled generator a is connected to the input of the tee, the first output of the tee is connected to the input of the first radio frequency amplifier, the output of the first radio frequency amplifier is connected to the first input of the oscilloscope, the second output of the tee is connected to the first input of the first adapter, the output of the linear-frequency-modulated filter module is connected to the second input of the first adapter , the output of the first adapter is connected to the input of the second radio frequency amplifier, the output of the second radio frequency amplifier is connected to the input of the amplitude detector, the output of the amplitude detector is connected to the input

Description

The utility model relates to metrology, namely to electronic measurements, and can be used to measure the parameters of complex signals of electronic blocks, as well as when sorting modules of linear-frequency-modulated (hereinafter ChF) filters during their production.

A device is known for monitoring the parameters of chirp signals (AS USSR No. 1200186), containing four differentiating chains, two amplitude detectors, two triggers, three delay lines, three threshold blocks, a shaper of reference pulses, four I elements, a shaper of the measurement interval, three pulse counter, two amplifier-limiter, phase shifter, mixer, low-pass filter, peak detector, gated amplifier, two subtracting units, attenuator. The device provides enhanced functionality and increased measurement accuracy.

A known signal analyzer with linear frequency modulation (AS USSR No. 1718136), containing two band-pass filters, two amplitude detectors, a trigger, a pulse generator, four counters, two registers, two keys, four matching elements, two arithmetic blocks, a threshold block , two unipolar valves, a phase inverter, a frequency detector and a differentiating unit. The device provides an extension of functionality by measuring signal parameters with various laws of linear frequency modulation.

A device for measuring the parameters of the chirp signals (AS USSR No. 1734033) containing a delay line, two phase shifters, a mixer, an intermediate frequency amplifier, three pulse counters, two amplitude detectors, an amplifier-limiter, two And elements,

a subtracting unit, a divider, a multiplier, an indication unit, a differentiating circuit, an adjustable delay unit, a counting interval generating unit, an adder, a crystal oscillator and a memory unit. The device provides enhanced functionality by measuring the duration and frequency deviation of the chirp signals and improving the accuracy of measuring the parameters of single chirp signals.

The prototype of the utility model is a device for measuring the frequency deviation of the LFM oscillations (AS USSR No. 1190281), containing a sawtooth voltage generator, a controlled generator, a phase detector, a reference generator, an indication unit, a key, a low-pass filter, a direct current amplifier, a shaper unit pulses, standardization unit and crystal oscillator. The device provides improved measurement accuracy.

All these devices have common drawbacks: circuit complexity, insufficient accuracy when measuring the parameters of the input and output signals of the LFM filter module, as well as insufficient visualization of the processes for measuring the parameters of these signals.

The task to which the utility model is directed is to expand the arsenal of technical means of the indicated purpose, namely, to create a device for measuring the signal parameters of the chirp filter module with a simplified circuit.

The technical result in the implementation of the utility model is the ability to simplify the circuit of the device for measuring the parameters of the LFM filter module signals, as well as expanding the device’s functionality, increasing the accuracy of measurements, increasing the completeness of measuring the parameters of the signals of the LFM filter and improving the visualization of the procedure for measuring the parameters of the input and output signals of the LFM filter .

To achieve the specified technical result in a device for measuring the deviation of the frequency of the chirp oscillations containing

a pulse shaper, a controlled generator, a key, instead of a sawtooth voltage generator, a quartz generator, a DC amplifier, a reference generator, a phase detector, a low-pass filter, a normalization unit, an indication unit and a control unit, a control voltage generator, a first video amplifier, a high-frequency generator are introduced, tee, first radio frequency amplifier, first adapter, second radio frequency amplifier, amplitude detector, second video amplifier, oscilloscope and LFM filter module. The first output of the pulse shaper is connected to the input of the key, the output of the key is connected to the first input of the control voltage generator. The second output of the pulse shaper is connected to the second input of the control voltage generator, the output of the control voltage generator is connected to the first input of the controlled generator. The output of the high-frequency generator is connected to the second input of the controlled generator. The third output of the pulse shaper is connected to the input of the first video amplifier, the output of the first video amplifier is connected to the third input of the controlled generator, the output of the controlled generator is connected to the input of the tee. The first output of the tee is connected to the input of the first radio frequency amplifier, the output of the first radio frequency amplifier is connected to the first input of the oscilloscope. The second output of the tee is connected to the first input of the first adapter. The output of the LFM filter module is connected to the second input of the first adapter, the output of the first adapter is connected to the input of the second radio frequency amplifier. The output of the second radio frequency amplifier is connected to the input of the amplitude detector, the output of the amplitude detector is connected to the input of the second video amplifier, the output of the second video amplifier is connected to the second input of the oscilloscope. The fourth output of the pulse shaper is connected to the third input of the oscilloscope. The LFM filter module contains a first repeater, a first intermediate frequency amplifier, a second repeater, a second adapter, a third repeater, a second intermediate frequency amplifier, a fourth repeater and a LFM compressive

filter. The output of the first repeater is connected to the input of the first intermediate frequency amplifier, the output of the first intermediate frequency amplifier is connected to the input of the second repeater, the output of the second repeater is connected to the first input of the second adapter. The LFM output of the compression filter is connected to the second input of the second adapter, the output of the second adapter is connected to the input of the third repeater. The output of the third repeater is connected to the input of the second intermediate frequency amplifier, the output of the second intermediate frequency amplifier is connected to the input of the fourth repeater. The LFM compression filter can be performed with either an increasing dispersion characteristic or a decreasing dispersion characteristic. In this regard, the LFM module of the compression filter also has a decreasing or increasing dispersion characteristic, respectively.

Figure 1 presents a diagram of a device for measuring the parameters of the signals of the chirp filter module.

Figure 2 presents the structural diagram of the module of the chirp filter with a decreasing or increasing dispersion characteristic.

Figure 3 shows the waveform of the input stretched signal for the LFM filter module with a decreasing dispersion characteristic (LFM signal with increasing frequency).

Figure 4 shows the waveform of the input stretched signal for the LFM filter module with increasing dispersion characteristic (LFM signal with decreasing frequency).

Figure 5 shows the waveform of the output compressed signal of the module of the chirp filter with a decreasing dispersion characteristic, recognized as suitable for use.

Figure 6 shows the waveform of the output compressed signal of the module of the chirp filter with a decreasing dispersion characteristic, recognized unsuitable for use.

The device for measuring the parameters of the signals of the LFM filter module contains a pulse shaper 1, a key 2, a control voltage generator 3, a first video amplifier 4, a high frequency generator 5, a controlled generator 6, a tee 7, a first radio frequency amplifier 8, a first adapter 9, a second radio frequency amplifier 10, an amplitude detector 11, a second video amplifier 12, an oscilloscope 13, and a chirp filter module 14. The first output of the pulse shaper 1 is connected to the input of the key 2, the output of the key 2 is connected to the first input of the generator 3 of the control voltage. The second output of the pulse shaper 1 is connected to the second input of the control voltage generator 3. The output of the control voltage generator 3 is connected to the first input of the controlled generator 6. The output of the high frequency generator 5 is connected to the second input of the controlled generator 6. The third output of the pulse shaper 1 is connected to the input of the first video amplifier 4, the output of the first video amplifier 4 is connected to the third input of the controlled generator 6. The output of the controlled generator 6 is connected to the input of the tee 7, the first output of the tee 7 is connected to the input of the first amplifier 8 of the radio frequency. The output of the first radio frequency amplifier 8 is connected to the first input of the oscilloscope 13. The second output of the tee 7 is connected to the first input of the first adapter 9. The output of the LFM module 14 is connected to the second input of the first adapter 9. The output of the first adapter 9 is connected to the input of the second radio frequency amplifier 10, output the second radio frequency amplifier 10 is connected to the input of the amplitude detector 11, the output of the amplitude detector 11 is connected to the input of the second video amplifier 12, the output of the second video amplifier 12 is connected to the second input of the oscilloscope 13. The fourth output pulse generator 1 is connected to the third input of the oscilloscope 13. The LFM filter module 14 contains a first repeater 15, a first intermediate frequency amplifier 16, a second repeater 17, a second adapter 18, a LFM compression filter 19 (with decreasing or increasing dispersion characteristic), the third repeater 20 ,

a second intermediate frequency amplifier 21 and a fourth repeater 22. The output of the first repeater 15 is connected to the input of the first intermediate frequency amplifier 16, the output of the first intermediate frequency amplifier 16 is connected to the input of the second repeater 17. The output of the second repeater 17 is connected to the first input of the second adapter 18. ChF output the compression filter 19 is connected to the second input of the second adapter 18, the output of the second adapter 18 is connected to the input of the third repeater 20. The output of the third repeater 20 is connected to the input of the second amplifier 21 in between of the second frequency, the output of the second intermediate frequency amplifier 21 is connected to the input of the fourth repeater 22. The first repeater 15 decouples the output complex resistance of the controlled oscillator 6 and the input complex resistance of the first radio frequency amplifier 8 from the input complex resistance of the first intermediate frequency amplifier 16. The second follower 17 decouples the impedance of the output complex resistance of the first intermediate frequency amplifier 16 from the input complex impedance of the LFM of the compression filter 19. The third follower 20 decouples the impedance of the complex impedance of the LFM of the compression filter 19 from the input complex resistance of the second intermediate frequency amplifier 21. The fourth repeater 22 decouples the impedance of the output complex resistance of the second intermediate frequency amplifier 21 and the input complex resistance of the second radio frequency amplifier 10.

The device for measuring the signal parameters of the chirp filter module can operate in two measurement modes. In the first mode, the parameters of the signals of the LFM filter module with a decreasing dispersion characteristic are measured. In the second mode, the parameters of the signals of the LFM filter module with increasing dispersion characteristic are measured. Since the differences in the measurements of the signal parameters of the chirp filter modules with decreasing and increasing dispersion characteristics are insignificant, the first mode will be described in detail below.

measurement, that is, measurement and control of the parameters of the signals of the LFM filter module with a decreasing dispersion characteristic. For the second mode, only differences in measurements and control of the signal parameters of the LFM filter module with increasing dispersion characteristic will be indicated.

A device for measuring the parameters of the signals of the chirp filter module operates as follows. The device sets the parameters of the input signals, which are indicated in the passport for the module 14 of the chirp filter. To the first adapter 9 connect the module 14 LFM filter. From the pulse shaper 1 to the oscilloscope 13, which is made according to a two-channel circuit, pulses with an amplitude of U ₁ and a duration of T ₁ are received. These pulses synchronize the operation of the two channels of the oscilloscope 13, which allows you to observe on the screen of the oscilloscope 13 the input radio pulses and the output video pulses of the LFM filter module 14, as well as pulses in other parts of the device. To the generator 3 of the control voltage from the pulse shaper 1 pulses are received with an amplitude of U ₂ , a duration of T ₂ and with a delay of D ₂ relative to pulses with an amplitude of U ₁ . When measuring the parameters of the signals of the module of the LFM filter with a decreasing dispersion characteristic, the polarity of the pulses with an amplitude of U _{2 is} negative, while measuring the parameters of the signals of the module of the LFM filter with an increasing dispersion characteristic is positive. The first video amplifier 4 from the pulse shaper 1 receives pulses with an amplitude U _{3 of} constant polarity, a duration of T ₃ = T ₂ and a delay of D ₃ = D ₂ relative to pulses with an amplitude of U ₁ . The control voltage generator 3, made according to the integrator circuit, generates a sawtooth pulse voltage. When measuring the parameters of the signals of the LFM module of a filter with a decreasing dispersion characteristic, the polarity of its “saw” is negative and decreasing in absolute value, and the angle of inclination of the “saw” α is determined from the expression:

where T is the constant of the integrating circuit of the generator 3 of the control voltage, and

R ₁ is the resistance of the resistor in the feedback circuit of the control voltage generator 3;

R ₂ is the output impedance of the pulse shaper 1;

R ₃ - input impedance of a controlled generator 6;

U ₂ - the amplitude of the pulses supplied to the generator 3 of the control voltage from the shaper 1 pulses;

C is the capacitance of the capacitor in the feedback circuit of the control voltage generator 3.

When measuring the parameters of the signals of the module of the LFM filter with an increasing dispersion characteristic, the polarity of the “saw” is negative, but increasing in absolute value. In this case, the angle of inclination of the "saw" is determined from the expression:

The key 2 (made by electronic) is connected in parallel with the capacitor of the control voltage generator 3. At the input of the key 2 from the pulse shaper 1, pulses of constant polarity with an amplitude of U ₄ (pulses of zeroing the capacitor) of duration T ₄ and with a delay of D ₄ relative to pulses with an amplitude of U ₂ are received, changing the state of the key 2. During the formation of a sawtooth voltage by the generator 3 of the control voltage switch 2 is closed and its resistance along the transmission circuit of the analog signal is very large. After the formation of the sawtooth voltage to the key 2 from the pulse shaper 1, a pulse with an amplitude of U _{4 is} received, which unlocks the key 2. In this case, the resistance of the key 2 becomes very small. This change in the resistance of the key 2 provides a quick discharge of the capacitor

generator 3 of the control voltage until the next pulse with an amplitude of U ₂ . From the high-frequency generator 5, a continuous sinusoidal signal with a different initial cyclic frequency fn, where n = 1 or n = 2, depending on the measurement mode, is supplied to the controlled generator 6. When measuring the parameters of the signals of the LFM filter module with a decreasing dispersion characteristic, the initial cyclic frequency f1 is established at the output of the high-frequency generator 5. When measuring the parameters of the signals of the LFM filter module with an increasing dispersion characteristic, the initial cyclic frequency f2 is established at the output of the high frequency generator 5. When measuring the parameters of the signals of the module of the LFM filter with a decreasing dispersion characteristic, an LFM signal is generated at the output of the controlled generator 6, the law of which the cyclic frequency f (t) changes in time takes the form:

where f (t) is the cyclic frequency in hertz;

f ₁ - the initial cyclic frequency in hertz;

t is the time in seconds;

m is the rate of change of the cyclic frequency with a dimension of second ^-2 .

When measuring the parameters of the signals of the LFM filter module with an increasing dispersion characteristic, an LFM signal is generated at the output of the controlled oscillator 6, the law of which the cyclic frequency f (t) changes in time has the form:

where f ₂ is the initial cyclic frequency in hertz.

The first video amplifier 4 blocks the power of the controlled generator 6 for the duration of the absence of pulses with an amplitude of U ₃ .

To measure the parameters of the signals of the module 14 of the LFM filter in real operating conditions, it is necessary to apply to its input a stretched radio pulse of the LFM with an amplitude of several units

millivolt. At the output of the module 14 of the chirp filter, a signal of the order of several tens of millivolts is obtained. The parameters of the pulses of such small amplitudes on an oscilloscope are measured in noise with large errors. To reduce the measurement errors of the signal parameters, it is necessary to increase the input and output radio signals of the LFM filter module 14 before measuring them on the oscilloscope 13, which is ensured by the use of the first 8 and second 10 radio frequency amplifiers. The amplitude detector 11 selects modulo the envelope of the compressed signal at the output of the LFM filter module 14. The second video amplifier 12 amplifies the envelope of the compressed signal received at the output of the amplitude detector 11. After establishing the necessary parameters of the signals at the output of the pulse shaper 1 and at the output of the high-frequency generator 5, the following parameters of the input and output signals of the LFM filter module 14 are measured using an oscilloscope 13:

- the amplitude of the stretched first Up1 of the input pulse of the LFM filter module with a decreasing dispersion characteristic (for the module of the LFM filter with an increasing dispersion characteristic - the amplitude of the stretched second Up2);

- the duration of the stretched first Tr1 of the input pulse of the LFM filter module with a decreasing dispersion characteristic (for the LFM module of a filter with an increasing dispersion characteristic - the duration of the stretched second Tr2);

- the amplitude of the main measured Ugi of the main lobe of the output compressed pulse of the chirp filter module;

- the amplitude of the lateral first Ub1 of the first side lobe of the output compressed pulse of the chirp filter module;

- the amplitude of the lateral second Ub2 of the second side lobe of the output compressed pulse of the chirp filter module;

- duration of the main measured Tgi of the main lobe, measured by the amplitude level equal to 0.5 Ugi of the output compressed pulse of the chirp filter module;

- the measured delay of the time center of the main lobe of the compressed pulse D and relative to the temporary position of one of the pulses with an amplitude of U ₁ , the value of which is compared with the passport value of Dп for the LFM filter module. Next, the measured absolute absolute error of the delay is calculated:

For the output compressed signal of the module 14 of the LFM filter, the measured first suppression coefficient is calculated by the formula:

Next, for the signals of the module 14 of the LFM filter, the measured second suppression coefficient is calculated by the formula:

moreover, the dimension of amplitudes is volts, the dimension of durations and delays is microseconds.

The measured values of the output signal parameters Ugi, Tgi, Ki1, Ki2, ΔDp are compared with the certified values of Ugp, Tgp, Kp1, Kp2, ΔDp for module 14 of the LFM filter using the inequalities:

If all the inequalities (9) are satisfied simultaneously for the parameters of the output signal of the LFM filter module 14, then the LFM filter module 14 is considered suitable for use (Fig. 5). The LFM filter module is varnished, placed in a metal housing and sealed around the entire perimeter in order to prevent oxidation of conductors and radioelements. If at least one of the inequalities (9) is not satisfied for the output parameters of the LFM module 14, then the LFM filter module 14 is rejected and sent for repair. Figure 6 presents

waveform of the output compressed signal of the LFM module 14 of the filter, which is recognized as defective due to the failure of the inequality Ugi≥Ugp.

Claims (4)

1. A device for measuring signal parameters of a linear-frequency-modulated filter module, comprising a pulse shaper, a key and a controlled generator, characterized in that it contains a control voltage generator, a high frequency generator, a first video amplifier, a tee, a first radio frequency amplifier, a first adapter, a linear module a frequency-modulated filter, a second radio frequency amplifier, an amplitude detector, a second video amplifier and an oscilloscope, the first output of a pulse shaper connected to the input of the key , the key output is connected to the first input of the control voltage generator, the second output of the pulse generator is connected to the second input of the control voltage generator, the output of the control voltage generator is connected to the first input of the controlled generator, the output of the high-frequency generator is connected to the second input of the controlled generator, the third output of the pulse shaper is connected with the input of the first video amplifier, the output of the first video amplifier is connected to the third input of a controlled generator, the output of a controlled generator a is connected to the input of the tee, the first output of the tee is connected to the input of the first radio frequency amplifier, the output of the first radio frequency amplifier is connected to the first input of the oscilloscope, the second output of the tee is connected to the first input of the first adapter, the output of the linear-frequency-modulated filter module is connected to the second input of the first adapter , the output of the first adapter is connected to the input of the second radio frequency amplifier, the output of the second radio frequency amplifier is connected to the input of the amplitude detector, the output of the amplitude detector is connected to the input m second video amplifier, an output of second video amplifier connected to the second input of the oscilloscope, the fourth output pulse shaper is connected to the third input of the oscilloscope. 2. The device according to claim 1, characterized in that the linear frequency-modulated filter module comprises a first repeater, a first intermediate frequency amplifier, a second repeater, a second adapter, a third repeater, a second intermediate frequency amplifier, a fourth repeater and a linear frequency-modulated a compression filter, wherein the output of the first repeater is connected to the input of the first intermediate frequency amplifier, the output of the first amplifier of the intermediate frequency is connected to the input of the second repeater, the output of the second repeater is connected inen with the first input of the second adapter, the output of the linear-frequency-modulated compression filter is connected to the second input of the second adapter, the output of the second adapter is connected to the input of the third repeater, the output of the third repeater is connected to the input of the second intermediate frequency amplifier, the output of the second intermediate frequency amplifier is connected to the input fourth repeater. 3. The device according to claim 2, characterized in that the linear frequency-modulated compression filter is made with a decreasing dispersion characteristic. 4. The device according to claim 2, characterized in that the linear frequency-modulated compression filter is made with increasing dispersion characteristic.