SU935807A1 - Digital meter of current basic carrier frequency - Google Patents

Description

The invention relates to frequency measurement and can be used to measure the current value of the frequency of filling a radio pulse in the presence of interference.

A device that implements a period measurement method based on interval measurement is known to determine eNOJX by intersecting a series of fixed levels with a signal, followed by averaging these intervals, containing a reference frequency generator, a switch, a comparator, gates, and a recording device l.

A disadvantage of the known device is limited functionality.

The closest in technical essence to the present invention is a device comprising a series-connected reference frequency unit, a main switch and a comparison unit, 3

However, this device has insufficient accuracy due to the "stability of the steepness of the restructuring of the reference generator, and insufficient speed, due to the constant time of the reverse circuit with; in s1, therefore

The device is not suitable for measuring the frequency of filling of short noise rye pulses and signals with a fast frequency change.

The purpose of the invention is to expand the functionality of the device, i.e. measurement of the current frequency of filling short signals mixed with noise.

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This goal is achieved by the fact that in a digital meter of the current frequency of filling of a radio pulse, containing in series a reference frequency block,

15, the switch and the comparison unit, the series-connected analog-to-digital converter, the valve and the memory unit, the series-forming unit connected in series

20 strobe pulse, control unit and frequency registration unit, a quadrant connected in series, an additional switch, an adder and a maximum sampling unit, as well as a second memory unit and an orthogonal reference frequency unit whose output is connected to the second pass of the main switch when the input is orthogonal zhtalsm noA frequency is connected to the input of agaponya

frequency and the second output of the control unit, the second input of which is connected to the output of the maximum sampling unit, the third output of the control unit is connected to the third input of the main switch, the fourth output f of the control unit is connected to the second input of the first memory block, to the second input of the additional switch and to the first input of the quadrator, the second input of which is connected to the output of the comparison unit, the second input of the latter is connected to the output of the first memory block, while the first input of the second memory block is connected to the second output before olnitelnogo switch, the second output of the block memory soedinen- to a second input of the adder, a second input gate connected to the second output of the block forming the strobe pulse, the input of which is connected to the input of analog-converter and the input device bus.

The drawing shows a diagram of the proposed device.

The device contains a reference frequency block 1, a main switch 2, a comparison block 3, an orthogonal reference frequency block 4, an analog-to-digital converter 5, a valve 6, a memory block 7, a strobe pulse shaping unit 8, a quadrant 9 additional switch 10, a memory block 11 , the sudmator 12, the maximum selection unit 13, the frequency detection unit 14 and the control unit 15.

The device works as follows.

A mixture of a pulse-modulated signal and noise is quantized by time and amplitude in analog-digital converter 5 with a time-quantization frequency sufficient to maintain the frequency at the upper value of the measurement range. In the strobe pulse forging unit 8, the beginning and end of the signal is fixed and a strobe pulse is formed that opens the valve 6. In the memory unit 7, the quantized signal values are stored. The end of the strobe pulse triggers the control unit 15, which successively over the time switch 2 connects the reference unit 1 and the orthogonal frequency unit 4 to the comparison unit 3, these blocks store a fixed number of reference frequency periods f, specified as 31 ordinates with an interval between they are equal to the sampling time interval of the analog-digital generator 5. In the comparison unit 3, the frequency of the measured signal is compared with the reference frequency by the criterion of the minimum of the standard deviation or crit The maximum of mutual correlation.

A signal from the output of the comparison unit 3 through the switch 10 is recorded in the memory unit 11, previously passing a quad. After forging a second signal at the output of block 3

the comparison obtained by comparing the measured-frequency signal with an orthogonal reference frequency, this signal through the switch 10 enters the input of the adder 12, to the second input

which receives a signal from block 11. The output of adder 12 corresponds to the sum of squares of the correlation integrals. The signal from the control unit 15 changes the frequency of the reference frequency blocks, in the maximum selection unit 13, the output signals of the adder 12 are compared and the maximum value of the signal and the adder is fixed, and the frequency value corresponding to this maximum is recorded by the frequency detection unit 14. To reduce the analysis time, the sequence of reference frequencies is selected by dividing

the frequency interval where the desired frequency lies, in half. To determine the current value of the frequency in a short time interval, a small segment of the reference signal is set, followed by a stepwise shift of the signal under study in block 7. The control unit 15 sets the frequency obtained in the adjacent section as the initial frequency of the reference frequency.

The frequency functional value is controlled by the frequency detection unit 14.

The proposed device allows the measurement of the current frequency value in a wide dynamic range. The upper limit of measurement is due to the speed of the analog-digital converter. The measurement accuracy is determined by the number of periods of the reference signal. By varying the number of periods of the reference signal, it is possible to optimize the procedure for measuring signals with a modulation frequency mixed with noise over a wide range of carrier frequencies and deviations.

Thus, the proposed device allows to measure the value of the current frequency in a wide range of variations of the latter in a mixture with the image and reduce the measurement tolerance.

Claims (2)

1. USSR author's certificate 568902, cl. G 01 R 23/00, 1976. one 2. Skripnik Yu.A. Modulation measurements of the parameters of signals and -circuits. M., Soviet Radio, 2975, p. 10, fig. 1.2.