SU976404A1 - Device for tolerance checking of radio receiver real sensitivity - Google Patents

Description

(St) DEVICE FOR ADMISSION CONTROL

one

The invention relates to a technique for measuring parameters of a quadrupole and can be used to automatically control the sensitivity of radio receivers during their mass production.

A device for measuring the actual sensitivity of radio receivers is known, comprising a high frequency generator, a closed circuit of automatically setting the input signal including a variable attenuator, a selective filter tuned to the modulation frequency, and an automatic setting of the output voltage blocking filter tuned to the modulation frequency, a quadratic detector, a comparator with a reference voltage source, a volume control position control unit, and a delay unit, the element coincides Eni and data processing unit l REAL SENSITIVITY RADIO RECEIVERS

A disadvantage of this device is the insufficient speed due to the inertia of the closed circuit of automatic adjustment of the output voltage of the radio receiver and the quadratic detector.

The closest technical solution to the present invention is a device for measuring the sensitivity of radio receivers, containing

; high-frequency generator, adjustable attenuator, selective band-pass filter tuned to frequency modulation, unit for automatically setting the output voltage, blocking filter tuned to the modulation frequency, converting the actual value of the noise to

20 DC voltage, two-threshold and single-threshold comparators, a unit for controlling the position of the volume control of the monitored radio receiver, a maximum sensitivity unit, a logic unit and a display and recording unit (..

A disadvantage of this device is the low performance of monitoring the sensitivity of radio receivers, due to the considerable time of setting the output voltage of the radio receiver covered by the input signal by the closed circuit of its automatic installation.

The aim of the invention is to reduce the time control

The goal is achieved by the fact that in the device for tolerance control of the real sensitivity of radio receivers, containing a high-frequency generator, an output connected to the first input terminal of the device, a comb barrier filter whose input is connected to the input of the selective filter and to the second input terminal of the device, and the output through a band-pass filter connected to the input of the converter of the actual noise value to the DC voltage, a two-threshold comparator, whose two reference inputs are connected to the corresponding the inputs of the sources of reference voltages M and Vj, and its output is connected directly to one of the inputs of the block log, ik and through

control unit — with an actuator input mechanically connected to the volume control of a controlled radio receiver; a single-threshold comparator, the reference input of which is connected to the output of the voltage level matching unit, and its output through the second input of the logic unit is connected A de-noise Bybinero converter of the value of noise into a DC voltage is connected to the signal input of a single-threshold comparator, and the output of the selective filter is connected to the input of a two-threshold signal a control unit and a control input of a voltage level matching unit made with an adjustable reference voltage

The drawing shows a block diagram of the device.

The device contains a high-frequency generator 1 high frequency, a controlled radio receiver 2, comb barrier) and a filter 3 band-pass filter C, a current converter 5

noise values in DC voltage, selective filter 6, two-threshold comparator 7, control unit 8, actuator

9 one-threshold comparator 10, block 11 for matching voltage levels, block 12 of logic, block 13 of indication and recording, input terminals of device 1 and 15, and sources

reference stresses V, and V.

The device works as follows

The output voltage of the high-frequency generator 1, the value of which is set in accordance with the requirements of the technical specifications for checking the sensitivity of the monitored radio receiver, is fed to the input of the monitored radio receiver

2 The output voltage of the monitored radio receiver Z contains a useful signal with a frequency equal to the modulation frequency f of the high-frequency generator voltage and noise (f). The wanted signal is selected by a selective filter 6 tuned to the modulation frequency f. 1 The cumulative component of the output voltage is isolated and transformed into a constant

the voltage is connected in series by a comb-like ridge filtering filter 3, a band-pass filter 4, and a converter 5 of the effective value of noise to a constant voltage

The fencing filter 3 suppresses signals with frequencies f, 2f, 3f, etc.,: ensuring the operation of the device without turning off the modulation of the generator 1, the band pass filter C limits the frequency band noise

With a given input signal of the radio receiver, the voltage of the useful signal is generated at its load. The voltages at the reference inputs of the two threshold comparator can be chosen from the condition

. where and is the voltage at the lower reference input of the two-threshold comparator,

and. - voltage on the top of the pole

the nominal input of the two-threshold comparator;

L is the transmission coefficient of the selective filter voltage within its bandwidth. In this case, the threshold voltage and. lJyig, and the difference between them is determined by the conditions of a given installation error of the Standard output power at the output of the controlled radio receiver. At the time the voltage is applied to the input of the controlled radio receiver, the position of its volume control is arbitrary, therefore, in general, inequality (1) may not be satisfied In this case, the two-threshold comparator 7 issues a corresponding signal to the control unit 8. The executive mechanism 9 changes the position of the volume control of the monitored radio receiver until the inequality is fulfilled (1., at this moment logical units are fed to another input of logic block 12 from the output of a two-threshold comparator. Through time t, logic block 12 evaluates the voltage at the output of a single-threshold comparator 10 "This estimate corresponds to the verification of the sial-noise ratio specified by technical conditions n controlled radio receiver, i.e. kviIH, H, C) JUXVNV In this case, the noise level at the output of the monitored radio receiver can be determined from the following mathematical expression. WVIV Considering that the voltage on the load of the radio receiver is constant, checking the fulfillment of inequality (2) is reduced to the definition: above or below the set level, the noise voltage at the output is controlled by the radio receiver. The level is made from the following mathematical expression RIGIN mVM.H The noise level relative to the signal level is estimated by a single threshold comparator 10. The voltage transfer ratio to the voltage level matching unit 11 for the signal with frequency f can be chosen from the condition -il cwrH - b and 1 ang. Where Kl is the transmission coefficient for the voltage of consecutively connected blocks for an 11 mA signal. If the output of a monitored radio receiver 2 when a voltage is applied to its input is equal to the voltage specified in With the actual conditions for checking the actual sensitivity, Expression 2 is fulfilled, which corresponds to .Sm bn Shugl. and (the voltage at the signal input of the single-threshold comparator is less than the voltage at the reference input), .this single-threshold comparator b works and outputs a signal as a logical unit on one of the inputs of block 12 logic. From its output, the signal arrives at the display and registration unit 13, indicating the suitability of the monitored radio receiver according to the real sensitivity. Sang at the output of the monitored radio receiver 2 expression (2 does not execute, which corresponds to .and (the voltage at the signal input of the single-threshold comparator is greater than the voltage at the reference input), the single-threshold comparator 10 does not work and from its input to the input of the logic unit 12 the signal does not In this case, the display and registration unit indicates the uselessness of the monitored radio receiver in terms of real sensitivity. Experimental tests of the device have confirmed the reduction in the time of monitoring the real sensitivity is pleased on each product. (Formula of the invention. A device for tolerance control of the real sensitivity of radio receivers, containing a high-frequency generator, an output connected to the first input terminal of the device, a comb-type barrier, the stroke of which is connected to the input of the copy-filter, and the second input terminal of the device , and the output through a band-pass filter is connected to the converter's input, the current value of the noise in the DC voltage, a two-threshold comparator, whose reference inputs are connected They are connected to the corresponding inputs of the reference voltage sources Vf, j, c, and its output is connected directly to one of the inputs of the logic unit and through the control unit to the input of the actuator mechanically connected to the volume control of the controlled radio receiver, a single-threshold comparator, the input is connected to the output of the voltage level matching unit, and its output through the second input of the logic unit is connected to the input of the display and recording unit, which receives the following data | that, in order to reduce the monitoring time, the output of the transducer of the effective value k8 of noise to the residual voltage is connected to the signal input of the single-threshold comparator, and the output of the selective filter is connected to the input of the two-threshold comparator and to the control input of the voltage level matching unit made adjustable reference voltage. Sources of information taken into account in the examination of USSR author's certificate No. 7i + 372, cl. G 01 R 29/00, 1978 to 2 USSR certificate of the USSR according to application No. 2752516 / 18-21, cl. G 01 R. 29/26, 2.0.80 (prototype).

Claims (2)

Claim A device for tolerance control of the real sensitivity of radio receivers, comprising a high-frequency generator output connected to the first input terminal of the device, a comb filter, the input of which is connected to the input of the selective filter, and to the second input terminal of the device, and the output through the band-pass filter is connected to the input of the converter of the actual noise value to DC voltage, a two-threshold comparator, two reference inputs of which are connected to the corresponding inputs of the reference sources apryazheny \ / _Mo and \ / _nB, and its output is connected directly to one input of the logic unit and via the control unit - to the input of the actuator associated mechanically with a bolt / controlled radio bone regulator odnoporogovy comparator, the reference input of which is connected to the output of coordination of voltage levels, and its output through the second input of the logic unit is connected to the input of the display and registration unit, which means that, in order to reduce the monitoring time, the output of the current converter value is 97b4o4 8 The noise in the DC voltage is connected to the signal input of a single-threshold comparator, and the output of the selective filter is connected to the 5th input of a two-threshold comparator and to the control input of the voltage level matching unit, made with an adjustable reference voltage. 10 Sources of information taken into account in the examination 1 <. USSR copyright certificate If 744372, cl. G 01 R 29/00, 1978. 2, USSR Author's Certificate 15 for application No. 2752516 / 18-21, cl. G 01 R 29/26, 24,04.80 (prototype).