SU1334095A2 - Automatic device for checking sensitivity of radio receivers - Google Patents

Abstract

The invention is further to the invention according to the authors. № 894606 and provides increased reliability of control by taking into account the level of intrinsic noise of the radio. The device contains a local oscillator frequency remover 1, a mixer 2, a band-pass filter 3, a voltage stabilizing unit 4, an attenuator 5, a trigger 6, an automatic voltage setting unit 7, a data processing unit 8, a tunable frequency generator 9, a linearly varying generator 10 voltage, voltage offset element 11, extremator 12, comparator 13, shapers 14,18, 19 single pulses, storage elements 15.24, keys 16,23, switch 17, additional switch 20, noise meter 21, setpoint formation unit 22 signal-to-noise values and to troliruemy radio (IF) 25. By the introduction of the blocks 19-24 is determined by the noise level IF 25 which is used for forming a predetermined voltage level at the output 25. The IF-2-yl. with 1C ate SLE 00 ate MS)

Description

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The invention relates to Measurement Technique, can be used in automated systems for monitoring radio receivers and is an improvement of the invention according to the authors. St. No. 894606.

The purpose of the invention is to increase the reliability of the monitoring result by taking into account the level of the own noise of the radio receivers.

FIG. Figure 1 shows the structural electrical circuit of the device proposed; Fig. 2 stress diagrams for his work.

The device for automated monitoring of the sensitivity of radio receivers contains a local oscillator frequency remover 1, a mixer 2, a band-pass filter 3, a voltage stabilization unit 4, an attenuator 5, a trigger 6, an automatic voltage setting unit 7, a data processing unit 8, a tunable frequency generator 9, a generator 10 linearly varying voltage, voltage offset element 11, extremator 12, comparator 13, first form: 7–14 single pulses, first storage element (D) 15, first key 16, switch 17, second 18 and third 19 tors, single pulses, a further switch 20, the noise meter 21, a block 22 forming a set value signal schum, second key 23, second 24 and EM 25 .radiopriemnik controlled.

The device works as follows.

When any tuning range of the monitored radio receiver 25 is turned on, the voltage of its local oscillator is fed through puller 1 to the input of mixer 2. Voltage of generator 9 is applied to another input of mixer 2, the frequency of which can be tuned within the range of possible changes in the intermediate frequency of the monitored radio 25. From the mixer output 2, two frequencies equal to the sum and difference of the frequencies of the generator 9 are allocated by the bandpass filter 3, which passes the sum or difference frequency depending on whether from the LO below or above the received signal. Thus, at the output of the bandpass filter 3, a frequency voltage appears, approximately

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equal to the frequency at which the gain of the monitored radio receiver 25 is greatest. Block 4 provides the constant voltage of this frequency at the output of the attenuator 5. From the output of the monitored radio receiver 25, through an additional switch 20, the level of intrinsic noise goes to the noise meter 21, the output voltage of which through block 22 and the second key 23 memorizes. c in the second ZE 24. The multiplication factor of block 22 is equal to the specified signal-to-noise ratio when measuring sensitivity. Thus, the voltage at the output of the second ZE 24 determines for block 7 the level of the specified voltage at the output of the monitored radio receiver 25. The block 7 provides the set voltage level ria of the output of the monitored radio receiver 25 by changing the voltage of the direct current at the control input of the attenuator 5, the control voltage equivalent to the high-frequency voltage at the antenna input is controlled Tuner 25 is supplied with the output unit 7 for measuring input data processing unit 8.

The output voltage of block 7, changing; it is in the negative region (Fig. 2g) is shifted to the positive region by the voltage shift element 11 (the change in the output voltage of the element 11 is shown in Fig. 2 e by a solid line).

The frequency of the generator 9 is controlled by the output voltage of the generator 10. The generator 9 must be tuned to a frequency that, combined with the local oscillator frequency of the monitored radio receiver 25, provides, at the auxiliary input, the maximum gain frequency, i.e. frequency f, on the frequency response of the controlled radio receiver 25 (Fig. 2e).

B moment t pulse Set. O (Fig. 2a) causes the extremator 12 and the first 15 and second 24 ZE to start up the third driver 19, which with its pulse connects the output of the controlled radio receiver 25 to the input of the additional switch 20 and closes the second switch 23. The pulse duration of the third driver 19 equal to the time required for measuring 3

the noise level (Fig. 2b), the noise level of the monitored radio receiver 25 is measured in the meter 21, multiplied in block 22 and stored through the second key 23 in the second ZE 24. The rear edge of the pulse of the third driver 19, affects the trigger input 19 , transfers it to the initial state, the first key 16 is disconnected, the output of the generator 10 is connected by a switch 17 to the control input of the generator 9. Starts to increase the voltage at the output of the generator 9.

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the course of the controlled radio receiver 25 corresponds to the first maximum of its frequency response and, consequently, to the first voltage minimum at the output of block 7 (Fig. 2g). The comparator 13 compares the output voltages of the voltage offset element 11 and the extremer 12 (Fig. 2e) dotted line). The first driver 14 starts a pulse with its output (Fig. 2h) briefly closes the first switch 16, and the voltage ( Fig. 2d) from the output of the generator 10 enters the first ZE 15 and is remembered (Fig. 2i).

Between t -4, the voltage at the output of element 11 decreases, and at the output of extremator 12 remains unchanged until, when approaching the next maximum frequency response, the voltage at the input of the comparator 13 increases, it reaches the level of the output voltage of the extremer 12 at another at the input of the comparator 13, the output of the comparator 13 returns to the initial state, with the first shaper 14 of a single pulse reversed

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neither does the comparator output start-up to increase the reliability of the monitoring result by taking into account the noise level of the radio receivers; a third generator of single pulses and a series connected additional switch, noise meter, signal-to-noise setpoint generating unit, second key and second memory are entered into it the element whose output is connected to the auxiliary input of the automatic voltage setting unit, the output of the third single pulse generator is connected to the set additional trigger inputs

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the course of the controlled radio receiver 25 corresponds to the frequency of the greatest amplification (Fig. 2d), the pulse from the first shaper 14 briefly closes the first key 16. In the first ZE 15, the voltage Uj is remembered (Fig. 2i) from the output of the generator 10 (Fig. 2d).

If the subsequent maximums of the frequency response of the controlled radio receiver 25 (Fig. 2e) are less than the maximum by hour55

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sweep the voltage of the generator 10, the output voltage of the extruder 12. and, consequently, the voltage on the first 33-15 does not change. Thus, the voltage stored in the first ЗЭ 15 (Fig. 2i), by the end of the sweep is equal to the output voltage and generator 10 (Fig. 2d), corresponding to the frequency of the input signal of the controlled radio receiver 25.

At time t by

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J. .1, the end of the sweep, the voltage of the generator 10 is reset to the initial value U, -, and the second driver 18 starts to reverse. The impulse from the second driver 18 converts the trigger 19 to state 1 (Fig. 2k), and the control 0 the input of the generator 9 is connected to the code of the first ZE 15.

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Since the transmission coefficient for the voltage of the first ZE 15 is one, the generator 9 generates a voltage with a frequency that, after mixing with the LO frequency of the monitored radio receiver 25, generates a signal at its input with frequency f (Fig. 2e, c), and unit 7 sets the lowest voltage (fig. 2g) corresponding to the receiver sensitivity parameter, the leading edge of potential 1 from the output of trigger 19 triggers on block 8 out of 5 (measuring the output voltage of block 7 and tuning frequency of the monitored radio receiver.

Claims (1)

Invention Formula A device for automated control of the sensitivity of radio receivers according to the author. St. No. 894606, which is characterized by the fact that 45 45 55 5133A0956 the switch and the second switch, the information input of the lock, the automatic input of the additional voltage setting, the input of the third switch is the output of the signal generator of single pulses Nala with controlled radio-p. and the second input of the second memory ka, and the second output of the additional switch is connected to the information element are input signals Set. ABOUT, element are input signal Set. ABOUT,