RU1810835C - Frequency meter - Google Patents

Abstract

The invention relates to the field of searchless high-frequency radio frequency meters in a wide range and can be used for electric frequency meters of weak signals with a spectral width not exceeding 1/5 of the bandwidth of one channel. It is achieved by introducing a circuit for computing the error signal 12 from two adjacent channels and converting it into a digital code by an analog-to-digital converter 13. Technically, economical generation of the error signal is achieved by using the well-known (AS 91746) electronic switch. The inventive multichannel meter contains an antenna 1 with a preselector, an attenuator 2, a frequency converter 3, an intermediate frequency amplifier 4, a key 5 with an inverse control input, a key 6, an amplitude limiter, filters 8-1-8-p, amplitude detectors 9-1-9-p, threshold blocks 10-1-10-p, switch 11, subtraction block 12, ADC 13, frequency adder-register 14 and OR element 15. 3 ill.

Description

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The invention relates to the field of high-precision radio frequency meters in a wide a priori range and can be used for electro-radio measurements of signal frequencies with a spectral width not exceeding 1/5 of a single signal bandwidth.

An object of the invention is to improve the accuracy of frequency measurement.

In FIG. 1 shows a functional diagram of a device; in FIG. 2 - amplitude-frequency characteristics of filters; in FIG. 3 - voltage versus frequency.

The device contains (Fig. .1) antenna 1 with a preselector, variable attenuator 2, frequency converter 3, intermediate frequency amplifier 4, key 5 with prohibition (prohibition of control input), key b, amplitude limiter 7, filters 8-1-8- p, amplitude detectors 9-1-9-p, threshold blocks 10-1-10-p, electronic switch 11, subtraction unit 12, analog-to-digital converter (ADC) 13, frequency adder-register 14, OR element 15.

The meter works as follows.

Filters 8-1-8-p multichannel systems are mutually overlapping on

At the level, amplitude-frequency characteristics (AFC) (Fig. 2), which fill the entire a priori frequency range. In the famous multi-channel meter

threshold voltage is from

input signal level slightly exceeding the sensitivity of the radio receiver. In the inventive meter, the threshold is selected so that at a given signal level determined by the amplitude limit Uorp (Fig. 2), detection would occur simultaneously in two channels H-1 and I in the presence of a signal with a frequency fi f fi -i. Corrective measurements are possible if the signal level is at least Uorp. The band of the resonant circuit of the 1st channel Po, in which the signal is detected, is

By P.707 Wooof Unop

With Uorp 2UnopJ According to П0.707.

If there is no signal with the expected frequency, there is no detection in all channels. -Therefore, there is no control voltage at the output of the OR 15 element. The key with inverse input 5 is open, and the key 6th is closed. When a UM U0rp signal appears with a frequency in the meter range, several threshold devices 91 + channels are triggered, where the signal level

exceeds the threshold element OR 15 generates a control voltage at the output, which locks the key with inverse input 5 and opens the key 6. After that, the signal is limited in amplitude. The maximum output signal of the multi-channel filter system 8 is normalized and detected by amplitude detectors 9-1-9-p. The threshold devices 10i, 10 | -and two (l + tj and f adjacent channels.

control voltages are fed to the input of the electronic switch 11, as well as to those high bits of the frequency register adder 14 to invert those triggers that correspond to the settings in binary code

fo +1 -Io,. ,,.,

--2 --- (l-H) -ro and 1st channel. The electronic switch 11 is constructed so that it always

a signal came from the (1 + 1) -th channel, and on the other from the i-ro channel.

The differential signal or error signal at the output of the subtraction unit 12 is input to an analog-to-digital converter

13, which writes the error signal in binary parallel code to the lower ones: bits of the frequency adder-register 14.

Thus, increasing the accuracy of a multi-channel frequency meter is achieved by normalizing and switching the inter-channel frequency response.

Claims (1)

SUMMARY OF THE INVENTION A frequency measuring device comprising a series-connected antenna with a preselector, a variable attenuator, a frequency converter and an intermediate frequency amplifier, n channels, consisting of series-connected filters, amplitude detectors and threshold blocks, as well as a frequency combiner, characterized in that that, in order to improve the accuracy of measuring the frequency, they are additionally introduced into it after well-connected subtraction unit and analog-to-digital converter, OR element, key with inverse control input, series-connected key and amplitude limiter, and electronic switch, the control inputs of which are connected to the outputs of the n threshold blocks, and the signal ones - to the outputs of the n amplitude detectors and the control inputs of the n threshold blocks, the outputs the electronic switch is connected to the inputs of the subtraction unit, the output of the analog-to-digital converter is connected to the lower bits of the adder-frequency register, the outputs of the threshold blocks are also connected to the corresponding inputs of the OR element and to the higher bits of the adder-frequency register, signal signals are connected to the output of the intermediate-frequency amplifier the key and key inputs with an inverse control input whose output and the output of the amplitude limiter are connected to the inputs of n filters, and the output of the OR element is connected to the control input to the key and to the inverse key input with an inverse control input. and, oh  KL /) pl Hh /with  OS fei i + t) 11o. Goth  eti y) 7 YaRig.2 o ()