RU2011292C1 - Automatic frequency control unit - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: AGC unit has counters, controlled oscillator, pulse-phase detector, code comparator, digital-to-analog and analog-to-digital converters, memory register, control signal subtracter and shaper. EFFECT: enhanced accuracy of automatic frequency control, in particular, by using the phase difference, measured at the beginning and end of the radio pulse, converted into direct voltage for correction of the control effect on the controlled oscillator. 1 dwg

Description

 The invention relates to techniques for measuring parameters of radio signals, can be used when digitally generating a delayed radio pulse used to test a radar, as well as in automatic frequency control devices.

 Known automatic frequency control systems containing a mismatch sensor on which an error signal (frequency difference) is generated, which is transmitted through the amplifier and the low-pass filter to the control element of the output generator and thereby monitors the output frequency by the input signal, as well as circuits based on the formation of the measuring time interval and counting the number of pulses of the carrier frequency of the input radio pulse and the pulses of the output generator for this interval, followed by a digital comparison of these results and generation of control signal based on this comparison.

 Closest to the proposed invention, the technical solution is a device containing a controlled generator, a digital-to-analog converter, dividers of the input and output frequencies of the signals, an element for comparing codes, a gate generator and an integrator. The signal chain formed at the output of the comparison element by the ratio of codes in the divider counters forms the control channel for the controlled generator.

 The disadvantage of this scheme is the low speed, since the signals that generate the error signal are taken from the dividers, and also, given the integrator, and when the input signal is short, they do not provide a determination of the frequency mismatch by one radio pulse.

 The purpose of the invention is to increase the speed of the automatic frequency control, which allows the use of short radio-pulse signals at the input.

 This is achieved by the fact that a frequency control device containing a serially connected controlled generator, a first counter, a code comparison element and a digital-to-analog converter, the output of which is connected to the control input of a controlled generator, and a second counter, whose input is the device input, are connected in series with a pulse -phase detector, analog-to-digital converter, memory register and subtractor, which is a fast and accurate channel for frequency adjustment, in the output of which is a correction code received at the input of the least significant bits of the digital-to-analog converter, thereby precisely controlling the frequency of the output generator. To coordinate the operation of the entire device, a control signal generator is also introduced. The introduced phase detector acts as a converter of the instantaneous phase value at the beginning and end of the input radio pulse to a constant voltage, which is converted further into a code and calculated further into the difference of these phases to correct the control signal.

 The drawing shows a structural electrical diagram of the proposed device.

 The device comprises a second counter 1, a first counter 2, a controlled generator 3, a pulse-phase detector 4, a code comparison element 5, a digital-to-analog converter 6, an analog-to-digital converter 7, a memory register 8, a subtractor 9, and a control signal generator 10.

 The automatic frequency control device is implemented on widely used standard elements. A positive effect is achieved by the fact that by sampling the instantaneous values of the input signal at the beginning and its end, the fractional part of the period (in the form of a phase difference) of the carrier frequency of the input signal that fits into the measuring time interval, which is added to the whole part of these periods, is determined. This creates a more accurate control signal of the output generator.

 (56) Kononovich L.M. Modern broadcasting receiver. M .: Radio and communication, 1986, fig. 77, p. 93.

Claims (1)

 AUTOMATIC FREQUENCY CONTROL DEVICE, containing a serially connected controlled oscillator, a first counter, a code comparison element and a digital-to-analog converter, the output of which is connected to the control input of a controlled generator, as well as a second counter, the input of which is the input of the device, characterized in that, in order to improve accuracy auto-tuning, the first and second counters are equipped with count and reset enable inputs, the code comparison element is equipped with fix and transfer inputs, digital-to-analog conversion The caller is equipped with a low-order input and a pulse-phase detector, an analog-to-digital converter, a memory register and a subtractor are inserted in series, the second input of which is connected to the output of the analog-to-digital converter, the code output is connected to the low-order input of the digital-to-analog converter, and the transfer output - to the transfer input of the comparison element, the first and second inputs of the pulse-phase detector are connected to the input of the second counter and the output of the controlled generator, as well as the driver their signals, the start input of which is connected to the input of the second counter, the synchronization input - with the output of a controlled generator, the output of the count resolution pulse - with the resolution enable inputs of the first and second counters, the output signal of the end of the radio pulse is connected to the control input of the analog-to-digital converter and the element fixation inputs code and subtractor comparisons, the output signal of the beginning of the radio pulse is with the reset inputs of the first and second counters and the memory register lock input, the output of the second counter is connected to the second electronic input ment comparisons codes.

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