SU478261A1 - Digital device for optimal signal frequency measurement - Google Patents

Description

(54) DIGITAL DEVICE FOR OPTIMUM

MEASUREMENT OF FREQUENCY SIGNAL

one

The invention relates to the field of radio metering technology and can be used in radiolocation (radio navigation, radio control, etc.) and other areas of technology where it is necessary to measure the frequency of electrical signals against a background of noise.

A device is known for optimal frequency measurement, which performs convolution operations of a received signal with an expected signal, detection and calculation of the error between the received and expected signals.

With the analog version, the known device has a number of drawbacks that make it difficult to use these devices for accurate frequency measurements. For example, using analog equipment practical. It is impossible to form a reference signal with strictly specified parameters, 20 or to build a filter whose pulse response exactly corresponded to the temporal representation of the signal, besides that, the parameters of analog devices are subject to changes under the influence of about 26

| steering environment. A significant drawback is the impossibility of using these devices when working with signals of various shapes. The transition from one type of signal to another requires significant hardware processing.

The purpose of the invention is to improve the accuracy and expansion of the functional possibilities of the device.

This goal is achieved by the fact that the proposed device is equipped with two argument generators, an amplitude generator, four registers, sine and cosine trigonometric transducers, and an adder, with the input of the multiplication unit connected to the output of the analog-code converter directly and through the first register, the second multiplier input is connected to the amplitude generator directly and through the second register, the third input of the multiplier through the sine and n functions serially connected trigonometric transducer The first argument generator is connected to the first output of the control unit, the fourth input of the multiplication unit is connected in series with the third register and the trigonometric transducer of the cosine function is connected to the output of the first argument generator, which through the successively connected fourth register and the second argument generator under ;; at the second exponent of the control unit 7, the outputs of the multiplication unit are connected to the inputs of the resolver, the code of which is connected to one of the inputs of the adder, and the second input The adder is connected to the third code of the control unit, the fourth output of which is connected to one of the inputs of the resolver. To implement the amplitude-frequency discriminator operations, the decisive ycT solver is equipped with four accumulators, four quadrants, three adders Two square root extraction blocks, a subtraction unit for the ratio calculator, the multiplication unit and the factor generator, the output of the first and second accumulators, the first, one, one, one, one, one and one, one, one, one, one, one, one, one, one, one, one Better, one for another. the third adder and the third and fourth accumulator drives through the third and fourth quadrants are connected to the inputs of the second sum of the torus, the output which is connected via the square root extraction unit to the input of the third adder and the input of the reading unit, the second input of which is connected to the second input of the third adder and through the second square root extraction unit to the output of the first adder, while the output of the third accumulator is connected to the ratio calculator to the input of the multiplication unit, the second input of which is connected to the output of the coefficient conditioner, and the output of the reading block is connected to the input of the block and the number of the ratio. The drawing shows a block diagram of the proposed device. The device contains a band-pass filter 1, analog-code converter 2, regist 3, multiplying device 4, argument generators 5 and 6, register 7, trigonometric converters 8 and 9, amplitude generator 10, registers 11 and 12, drive 13, quad 14, tip 15, square 16, tip 17 quad 18, naxiogep 19, Iceaflpa TOp 20, summato)) 21, square root extraction unit 22, adder 23, square root extraction unit j 24, subtracter 25, sumattor 26, ratio calculation unit 27, multiplying device 28, shaper coefficients 29, the control device 30, the adder 31 and the resolver 32. The digital device for optimal measurement of the signal frequency works as follows: Input signal U (t) -U (t) cos (2f / i d, where f is the signal frequency to be measured. After the passage of the bandpass filter 1 is encoded in converter 2 into I discrete points in time, the sampling interval is D1, from the sampling condition of narrowband signals is equal to ui TDR F - bandwidth of the band filter 1. Synchronously with the time quantization of the input signal in the argument generators 5 and 6 at the moments of time Ut, the arguments If 21 fo + D f) ku t and 45.-2lI (fo-4f) kat are formed, where f is the expected value of the signal frequency, Suf is the width of the frequency discriminator. The arguments f and | 1 "are formed according to the program defined by the control device 30. The trigonometric converters 8 and 9 form the functions .Ti (f0-t-4f) kat: i and () kA t J. which are consecutively BO time (COS f functions are stored in register 12) are sent to the multiplying device 4, where they are multiplied with the code value k - OI signal sampling NLk and with the expected signal amplitude generated in the amplitude generator 10. From the output of the multiplying device, the values of ek N klu k sinLaf ( ) kAtl i ALk N ku klcos a1T (fotuf) kAt go to drives 13 and 15. Then to the set itelnom device 4 are calculated - 8 values, k N klulklsm 2li (fo-4f) kAt; Ai k -Ntklulk cos 2ir (fo-Af) kAt by multiplying the stored in registers 3 and 11 origins NLk and K by the COS and 51P functions of the argument ", stored in register 7. The values of A, Ik U entered into the accumulators 17 and 19. The timescale for the values Alk,, e, exceeds the sampling interval of the input signal D t.