SU1751693A1 - Device for measuring attenuation non-uniformity of electromechanical filters - Google Patents

Abstract

Usage: the invention relates to radio engineering, namely to the production of electromechanical filters, and allows to automate the measurement process and improve the measurement accuracy of the non-uniformity of filter attenuation. SUMMARY OF THE INVENTION: A clock pulse generator 1 determines the cycle of operation of a device. When the button 2 is turned on with a clock pulse, the oscillating frequency generator 3 starts up. From the oscillator 3 oscillating frequency, the signal is fed to the input of the filter under study 4. The envelope of the amplitude-frequency characteristic of the filter is selected by detector 5. This voltage is fed to the input of comparator 6 and the input of comparator 7. The search for the highest point of the filter's amplitude-frequency characteristic is performed by a circuit including a counter 8, a digital-to-analog converter 9 and a comparator 6. The search for the lowest point (extremum) of the amplitude-frequency characteristic is carried out with the help of a circuit including a counter To 11, a digital-to-analog converter 12 and a comparator 7. To eliminate the false triggering of the comparator 7, an extremizer 17 is inserted into the device. The key 13 from the extremator 17 opens, and the signal from the comparator 7 to the trigger 14 arrives only when the minimum extremum on the amplitude-frequency filter bandwidth characteristic. The voltage from the output of the trigger 14 is fed to the input of the resolution of the operation of the block 15 dividing numbers. The result of the division is indicated by the indicator 18. From the output of the trigger 14, the voltage is also fed to the input of the reset unit 16, which, after an interval of time specified by the operator, resets the triggers 10 and 14 and the counters 8 and 11. Then the cycle repeats. The switching of circuits in a predetermined sequence is performed by electronic switches 13 and 19 and triggers 10 and 14. 3 sludge. j w Ј V | sl 5 with phage1

Description

The invention relates to radio engineering, in particular to the production of electromechanical filters.

A device for measuring damping non-uniformity is known, comprising an electrical oscillator, a frequency meter, a filter under study, and a voltmeter. By varying the oscillator frequency, the extremal maximum and minimum values of the voltage on the amplitude-frequency characteristic (AFC) of the filter in the passband are determined and the non-uniformity of attenuation is determined using known formulas.

However, this device does not measure the filter parameter without the processing of information by a human.

A device for automatic tolerance control of non-uniformity of the frequency response is known, comprising a oscillating frequency generator, a detector, a signal maximum meter, comparators, a recording unit, an indicator, as well as dividers, memory elements and a comparison.

A disadvantage of the known device is the impossibility of quantifying the non-uniformity of the frequency response of the filter, which does not allow monitoring the progress of the filter manufacturing process.

The purpose of the invention is to expand the functionality of the device by providing a quantitative control of the unevenness of damping.

electromechanical filter.

This goal is achieved in that a device containing a series-connected oscillating frequency generator, a test filter, a detector, as well as a maximum signal meter with one comparator, another comparator, a recording unit, and an indicator, besides the maximum signal meter consisting of the first counter in series. , the first digital-to-analog converter and the first comparator, a minimum bandwidth of the amplitude-frequency characteristic in the passband consisting of connected to the second counter, the second digital-to-analog converter and the second comparator, and a control circuit consisting of a clock generator, which through its start button is connected to the input of a swept frequency generator and the counting inputs of the first and second counters, an extremer whose input is connected; the output of the detector, and the output with the control input of the first electronic key, two

the triggers, the first of which is connected to the output of the first comparator by its installation input to the O, and the second electronic input through the first electronic key to the output of the second comparator through the same input. In addition, the output of the first trigger is connected to the control input of the first counter and the control input of the second electronic key; the output of the second trigger is connected to

control input of the second counter, as well as via the second electronic key - with the enable input of the registration unit as a divisor unit and the launch input of the reset device connected by its outputs to the installation inputs of the first and second triggers and the reset inputs of the first and second counters and the meter outputs are associated with the first and second inputs, respectively.

block dividing numbers to which the indicator is connected.

The proposed device is different from

known for the presence of two circuits: the amplitude-frequency minimum allocation circuit

characteristics and control circuits.

FIG. 1 shows a block diagram of a device for measuring the attenuation unevenness of a filter; 2 and 3 are timing diagrams of the voltages at the output of the functional units.

The device works as follows.

To make measurements, it is necessary to use the start button 2 to close the generator of 1 clock pulses - oscillator 3 of the oscillating frequency. The generator 1 clock pulses produces clock pulses (figure 2. Chart 1). The first clock pulse is fed to the start input of the oscillating frequency generator 3, which operates in the standby mode and is triggered by each successive pulse (Fig. 2, Chart 2). A oscillating frequency generator generates alternating voltages with

linearly increasing frequency, which is fed to the input of the amplitude detector 5, which produces a voltage corresponding to the amplitude-frequency characteristic of the filter 4 (Fig.2, diagram 3).

This voltage is fed to the second input of the comparator 6 and the first input of the comparator 7. At the same time, the clock pulses from the generator 1 are fed to the input of the reverse count of the reversible counter 8, which at the beginning

each measurement cycle is set to a single position. The digital information contained in meter 8 is fed to the input of the first digital-to-analog converter 9, where it is converted into a voltage determined by the state of the meter. So

Thus, the voltage at the output of the digital-to-analog converter 9 has p d and tertiary levels from a certain maximum value to zero (figure 2, diagram 3).

The voltage from the output of the D / A converter 9 is fed to the first input of the comparator 6. As soon as the voltage at the first input of the comparator 6 becomes less than the voltage at the second input of the same comparator (figure 2, diagrams 3 and 5. point K), its input appears the voltage that enters the input of the installation in the O of the trigger 10 and transfers it to a state prohibiting the further counting of the counter 8.

Thus, in meter 8, the maximum value of the amplitude-frequency characteristic in the passband of the filter is stored in digital form.

The digital information from the output of the counter 11 is fed to the input of the digital-to-analog converter 12, where it is converted into a voltage. The output voltage of the digital-to-analog converter 12 has n discrete levels from zero to some maximum value. This voltage is supplied to the second input of the comparator 7. As soon as the voltage at the second input of the comparator 7 becomes greater than the voltage at the first input (Fig.2, Chart 3, point I), a voltage appears at the output of the comparator 13 (Fig. 2, diagram 6) is applied to the input of the installation in O of the trigger 14, which is transferred to the state prohibiting further counting of the counter 11. Thus, in the counter 11, the voltage equal to the extreme minimum amplitude-frequency value is stored in the digital meter 11 characteristics in the band pr lowering the test filter (at point I).

To eliminate the false triggering of the comparator 7, for example, at the points K-1 and K + 1 (Fig. 2, diagram 3), the key 13 is opened by voltage from the extremizer 17 (Fig. 2, diagram 4) only at the time point corresponding to the extreme values m of amplitude-frequency characteristics of the studied filter u. 2, diagram 4).

The possible discrepancy in time of occurrence of pulses at the outputs of the comparator 7 and the extremizer 17 due to the difference in the delay times in the operation of the latter does not lead to a malfunction of the device. In this case, the counter 11 stops with the arrival of the next clock pulse, since at the next clock the voltage at the output of the DAC 12 increases by one step, which causes the pulse at the output of the comparator 7 (fig. 3) to expand (increase in duration) by the latter triggers at points 1-1 and 1 + 1. This leads to the overlap in time of the pulses from the outputs of the comparator and extremator. 5 The voltage from the output of the trigger 14 is also fed to the input of the resolution of the block 15 dividing the number. The result of the division is indicated by the indicator 18. From the output of the trigger 14, the voltage also goes to

10 is an input of the reset unit 16, which, after a time interval counted from the moment of the occurrence of voltage at the output of the trigger 14 and set by the operator, resets the triggers 10 and 14 and

15, the counter 3 and the zero position of the counter 11. The measurement cycle is repeated. When using the proposed device, manual operations for rebuilding generators and recording are excluded.

0 results when measuring the non-uniformity of filter attenuation.

Claims (1)

The invention The device for measuring the attenuation of electromechanical attenuation 5 filters containing a series-connected oscillating frequency generator, terminals for connecting the measurement object and an amplitude detector, as well as the first and second comparators and an indicator, which is characterized by the fact that, in order to extend the functionality by providing a quantitative control of the attenuation unevenness of the electromechanical filter, the first counter and the first digital-to-analogue converter, the second counter and the second digital-analogue are connected in series in it; new converter, first and second triggers, first and second electronic keys, block reset, extremator, block dividing numbers, and also serially connected clock generator and start button, the second output of which is connected to the counting 5 inputs of the first and second triggers and the input of the oscillating frequency generator, while the outputs of digital-to-analog converters are connected to the first inputs of the first and second comparators, respectively, 0 the second inputs of which are connected to the output of the amplitude detector and the input of an extremer, the output of which is connected to the control input of the second electronic key, the input of which is connected to the output of the second 5 comparator, and the output - to the input of the zero setting of the second trigger; the output of the first comparator is connected to the input of the zero installation of the first trigger; the output of the first trigger is connected to the control inputs first counter and first electronic key, the output of the second trigger is connected to the control input of the second counter and the input of the first electronic key, the output of which is connected to the input of the reset unit, the first output of which is connected to the installation inputs of the unit of the first and second triggers and the reset input of the first counter, and the second is connected to the reset input of the second counter, the outputs of the first and second counters are connected respectively to the first and second inputs of the divisor unit, the output of which is connected to the indicator, and the work enable input to the output of the first electronic key .. FIG. I