SU894606A2 - Device for automatic monitoring of radio receiver sensitivity - Google Patents

Description

(54) DEVICE FOR AUTOMATED MONITORING THE SENSITIVITY OF RADIO RECEIVERS

one

The invention relates to radiofrequency engineering and can be used in automated control systems for radio receivers.

According to the main author. St. No. 748289, a device for automated monitoring of the sensitivity of radio receivers is known in which the frequency of the input signal of the controlled radio receiver is formed from the voltage frequency of the local oscillator of this radio receiver and the fixed frequency of the oscillator equal to the standard intermediate frequency of the radio receivers. The device includes a prom weave frequency generator, a mixer, a local oscillator frequency remover, a frequency transfer filter, a voltage stabilization unit, an attenuator, an automatic voltage setting unit, a controlled radio receiver, and a data processing unit tl.

A disadvantage of the known device is a significant control error caused by a narrow band of the input circuits of the radio receivers when operating in the range of long frequencies, which is commensurate with the acceptable deviation. intermediate frequency from its standard value, and when operating in the medium and short ranges because of the frequency characteristic in the passband of the intermediate frequency amplifier (IF amplifier), most often occurs, for example,

10 application in the PIAC piezoceramic filters. Therefore, the frequency of the input signal generated by a known device may not coincide with the frequency of fine tuning of the monitored radio receiver 15, which causes the monitoring to stifle.

The purpose of the invention is to improve the accuracy of control of radio receivers.

This goal is achieved by the fact that

20 into a device comprising a serial oscillator, a local oscillator, a mixer, a band-pass filter, a voltage stabilization unit, and an attenuator connected in series. 38, a controlled radio receiver and an automatic voltage setting unit, the output of which is connected to the control input of the attenuator and to the input of the data processing unit, a linear voltage generator, element, is introduced. voltage shift, extremator, comparator, two single pulse impulse, memory element, key, switch and trigger; one of the comparator inputs is connected to the extremator input directly and through the voltage offset element - with the output of the automatic voltage setting unit and the second input the comparator is connected to the output of the extremmer, and the output of the computer, the rator, through the first driver of a single pulse is connected to the control input of the key, the output of which is connected to the first through the memory element the switch, the output connected to the input of the intermediate frequency generator, made tunable, and the second input of the switch is connected to the inputs of the key and the second driver of a single pulse and the generator voltage of the linearly varying voltage, the control input of which is connected to the control input of the switch, with the output of the trigger, the input connected to the output of the second driver of a single pulse, and with the second input of the data processing unit, the third input of which is connected to the input, the stabilization unit uu voltage, wherein adjusting the inputs of the memory element, the flip-flop and ekstrematora connected to Set input device. O In FIG. 1 shows a functional diagram of the proposed device; in fig. 2 - timing charts for the operation of the device. The device contains a local oscillator frequency remover 1, a mixer 2, a band-pass filter 3, a voltage stabilization unit 4 (BSN), an attenuator 5, a controlled radio receiver 6, a unit 7 auto: a mathematical voltage setting (BAUN processing unit 8 (WAT), a generator 9 tunable frequency (VFD), linearly varying voltage generator 10 (CLAY), voltage offset element 11, extremator 12, comparator 13, first single pulse generator 14 (PON), storage element (GE) 15, key 16, switch 17, Shoroy Foi 18, trigger 19. The device is running 6 When switching on any range of the monitored radio receiver 6, the voltage of its local oscillator is fed through the puller 1 to the input of the mixer 2, the other input of the mixer 2 is connected to the GHG 9. Frequency of the HRC 9 can be tuned within the range of possible changes of the intermediate frequency of the monitored radio receiver 6. From the output of the mixer 2 frequencies equal to the sum and difference of the frequencies of the local oscillator of the receiver and generator 9 are fed to a band-pass filter 3, which passes either the total or the difference frequency depending on whether Whether or below the local oscillator frequency f vp frequency of the received signal. Thus, at the output of the filter 3, a frequency voltage appears that is approximately equal to the frequency at which the gain of the receiver is greatest. BSN 4 provides the constant voltage of this frequency at the input of the controlled attenuator 5. BAUN 7 provides a predetermined voltage at the output of the controlled radio receiver 6 by varying the voltage of the direct current at the control input of the attenuator 5. The control voltage equivalent to a high-frequency voltage at the antenna input of the radio receiver 6, is fed from the output of the BAUN 7 to the measuring input BAU 8 for measurement, processing and recording. The output voltage of the BAUN 7, which varies in the negative region (Fig. 2b), is shifted to the positive region by the voltage displacement element 11 (the change in the output voltage of the element 11 is shown in Figure 2 V by a flat line). The frequency of the VFG 9 is controlled by the output voltage of GLINE 10. The VFG 9 must be tuned to a frequency that, in combination with the local oscillator frequency of the radio receiver 6, provides at the antenna input of the radio receiver 6 the frequency of maximum receiver gain, i.e. frequency - at the receiver frequency response (Fig. 25). The tuning of the HRC 9 is carried out as follows. At time t pulse Set. O reset the extremator 12, WE 15 and trigger 19; the key 16 is disconnected, the output of the CLAY 10 is connected by a switch 17 to the control input of the HPC 9. The voltage rise at the output of the CLAY 10 begins (Fig. 2 q () and the frequency of the voltage at the output of the FM 9 increases.

At time tQ, the frequency q at the output of the radio receiver 6 corresponds to the first maximum of the amplitude-frequency characteristic (AFC) of the radio receiver and therefore to the first minimum of the voltage at the output of BAUN 7 (Fig. 28). A comparator 13, which compares the output voltages of the voltage offset element 11 and the extremator 12 (Fig. 2.1, dashed lines), starts FOI 14. The impulse from FOI 14 (Fig. 2 a) short-circuits the key 16, and the voltage value (Jf (Fig. 2 d) from the output of the CLAY 10 enters the ZE 15 and is remembered (Fig. 2 e).

In the interval between tg and 3, the voltage at the output of element 11 decreases, and at the output, extremator 12 remains unchanged until when the voltage approaches the next maximum frequency response the input voltage of the comparator 13 reaches the level of the output voltage of the extremer 12 at the other input comparator 13; the output of the comparator 13 returns to its original state, while the single pulse shaper is not triggered by a reverse voltage drop at the output of the comparator.

At time tj, the frequency at the input of the radio receiver 6 corresponds to the frequency of the greatest gain of the radio receiver (Fig. 2-5 U; the pulse from the FOI 14 briefly closes the key 16. On WE 15, the voltage Ui is remembered (Fig. 28) from the output of GLR1N 10 ( Fig. 2

“).

If the subsequent max-frequencies of the AFC of the radio receiver 6 (Fig. 25) are less than the maximum at the frequency C (at time t), then until the end of the sweep of the GLINE 10 voltage, the output voltage of the extremum-mountain 12, and consequently, the voltage at the CE 15 does not change. Thus, the voltage stored in the DE 15 (Fig. 2B) at the end of the sweep is equal to the output voltage — GLINE 10 (FIG. 2d), corresponding to the frequency of the input signal of the radio receiver 6.

At time t / at the end of the sweep, the voltage of the CLAY 10 is reset to the initial value 0, run by reverse FOI 18. The impulse from FOI 18 switches the trigger 19 to state 1 (Fig. 2 g) j and the subsequent sweep of the voltage CLIN is prohibited 10, and the control input of the FNG 9 is switched off by the switch 17 from the output of the GLINE H and connected to the output of the DI 15.

Since the transmission coefficient for the VE 15 voltage is equal to one, the VO 9 generates a voltage with a frequency that, after mixing with the local oscillator frequency of the radio receiver, generates a signal with frequency fj (Fig. 2 V) at the radio receiver input, and the smallest the voltage uj (Fig. 26), corresponding to the receiver sensitivity parameter; The leading edge of the potential from the output of trigger 19 triggers on AAC 8 the measurement of the output voltage of the BAUN 7 and the frequency settings of the radio receiver.

The sensitivity of the radio receiver at an intermediate frequency that differs from the standard value of 465 kHz at t 2 kHz is measured with an error of no more than 10%, which provides a control accuracy of 5 times.

Claims (1)

Invention Formula Automated monitoring device for radio sensitivity according to aut. St. No. 748289, distinguished by the fact that, in order to increase the accuracy of control, a linearly varying voltage generator, an extremator, a comparator, two single pulse generators, a storage element, a key, a switch and a trigger, and one of the comparator inputs connected directly to the extremer inlet and through a voltage shift element to the output of the automatic voltage setting unit, and the second input of the comparator is connected to the extremizer output, and the output of the comparator through the first driver of a single and pulse is coupled to a control input of a key, which is output from the memory element connected to a first input of a switch output coupled to the input of the intermediate frequency oscillator. The second input of the switch is connected to the inputs of the key and the second driver of a single pulse and to the generator output of a linear-varying voltage, the control input of which is combined with the control input of the switch, with the input of the trigger. with the output of the second shaper of a single pulse, and with the second input of the data processing unit, the third input of which is connected to the input of the voltage stabilizer unit, the mounting inputs of the storage element, the trigger and the xfrefremator are connected to the input of the Device Set, O ,. (puf.l 6946 5 Set o 068 Sources of information taken into account during the examination 1. USSR Author's Certificate No. 748289, cl. Q 01R 27/28, 1978 (prototype).