RU1810984C - Adjustable wide-band filter - Google Patents

Abstract

Usage: radio engineering, transceiver and measuring equipment. The inventive wide-range tunable filter contains 2 directional couplers (1,3), 2 frequency-selective element (2) in the form of a microwave filter on magnetostatic waves, 1 phase discriminator (4), 1 reversible search signal generator (5) containing 1 generator clock pulses (6), 1 reverse counter (7) and 1 code-analog converter (8), 1 control element (9), 1 amplitude detector (10), 1 threshold element (11), 1 reverse counter (12) , 1 comparison element (13) and 1 key (14). The presence of a reversible search signal generator (5) allows the filter to be tuned by the range, the reversible generator (5) stops at the moment of equality of the current and the set frequency number codes, after which the phase-locked loop is turned on, which performs fine tuning of the filter. 1 ill. ate

Description

-H - GMZ

The invention relates to radio engineering and can be used in transceiver and measuring equipment as high-resolution filter circuits.

The purpose of the invention is to increase the accuracy of tuning to a given frequency from a grid of input frequencies when performing a frequency-selective element in the form of a microwave filter on magnetostatic waves.

The drawing shows a block diagram of the proposed device.

The device comprises a first directional coupler 1, a frequency-selective element 2 on magnetostatic waves, a second directional coupler 3, a phase discriminator 4, a reversible search signal generator 5, consisting of a clock pulse generator 6, a reverse counter 7 and a code-to-analog converter 8, a control a measuring element 9, an amplitude detector 10, a threshold element 11, a counter 12, a comparison element 13 and a key 14.

The device operates as follows.

When turned on, the reversible counters 7 and 12 are reset. At the inputs of the comparison element 13, a frequency number code is received. In this case, the output is equal to the comparison element 13 to the control input of the key 14 and, to the stop input of the clock generator 6, a signal is received at which the key 14 disconnects the output signal of the phase discriminator 4 from the first input of the control element 9, the clock generator 6 is started. output more / less than the comparison element 13 to the control inputs of the reversible counters 7 and; 2 the signal of setting the summation mode is input. The signal from the generator of those pulses 6 is fed to the reversible counter 7 and then in the form of a parallel code to the converter "analog-to-analog 8, the step-like sawtooth voltage from the output of which goes to the second input of the control element 9. In this case, the resonance frequency of the frequency-selective element 2 to a given frequency number. When the filter is tuned to the frequency range, the signals of the input grid pass through it sequentially, forming a pulse train at the output of the amplitude detector 10, which, through the threshold element 11, enters the counting input of the reverse counter 12. The parallel code from the outputs of the counter 12 enters the corresponding group of inputs of the comparison element 13, When the equality of the codes is reached, the output is equal to the comparison element 13, a signal appears that turns off the clock 6. In this case, the key 14 closes the phase-locked circuit adjusting the frequency of the filter, which performs accurate hydrochloric tuning filter.

When changing the frequency number, if the new frequency number is greater than the number previously set, the filter setup process is similar. If the new frequency number is less

numbers previously set, the filter configuration process is as follows. The output signal is equal to the element of comparison 13 through the key 14 opens the phase-locked loop, the clock pulse generator 6 is started. Simultaneous output of more / less than the element of comparison 13 to the control inputs of the reversible counters 7 and 12 receives the signal for setting the mode of subtraction. At the moment of equality of the codes, which corresponds to the occurrence of a given fixed frequency in the passband of the filter, at the output equal to the comparison element 13, a signal is generated that turns off the generator bis using the key 14

closing the phase-locked loop of the filter 2, thereby fine-tuning the resonant frequency of the filter to a given frequency from a grid of input fixed frequencies. Fine tuning is carried out as follows. If there is a deviation in the resonant frequency of filter 2 from a given fixed frequency, an error signal appears at the output of phase discriminator 4, which, through

the key 14 is supplied to the first input of the control element 9, and a control signal appears at its output, which allows the resonance frequency of the frequency-selective element 2 to be adjusted to a predetermined frequency from the input signal grid. Further operation of the phase-locked loop provides compensation for the thermal drift of the resonant frequency of the filter.

Thus, thanks to the proposed

the technical solution provides automatic tuning of the wide-band narrow-band microwave filter on magnetostatic waves from the frequencies of the fixed-frequency grid, the tuning accuracy is improved and

Compensation of thermal losses of the resonant frequency of the filter is provided.

Formula of the invention A wide range tunable filter comprising a frequency selective frequency tunable element, a phase discriminator whose inputs are connected respectively to the input and output of the frequency selective frequency tunable element, in series

connected by a reversible search signal generator and a control element, the output of which is connected to the control input of the frequency selective element, tunable in frequency, as well as an amplitude detector connected to the output of the frequency selective element, tunable in frequency, characterized in that in order to improve tuning accuracy at a given frequency from the input frequency grid when performing a frequency-selective element in the form of a microwave filter on magnetostatic waves; a key is inserted into it, connected between the output of the phase discriminator and another input of the control element, a threshold element connected in series to the output of the amplitude detector, a reverse counter and a comparison element, the other input of which is the input of the code number of the given frequency, as well as the first and second directional couplers, while the inputs of the phase discriminator are connected to the input and output of the frequency selective element, tunable in frequency, through the first and second directional couplers and accordingly, the amplitude detector is connected to the output of the frequency-selectable element, tunable in frequency, through a second directional coupler, the output of the More / less comparison element is connected to the input of the Counting direction of the reversible counter and the control input of the reversed search signal generator, the output is Equal the comparison element is connected to the control input of the key and the stop input of the reversed search signal generator, made in the form of series-connected clock pulse generator owls, down counter and the code converter - analog, wherein the stop input of the clock, input direction

the counters of the reversible counter and the output of the code signal converter are respectively the stop input, the control input and output of the reversible search signal generator.