SU1224738A1 - Digital converter for phase-meter - Google Patents

Abstract

The invention relates to an electronic radio measuring technique and can be used in the development of high-accuracy fuzometric devices. The purpose of the invention is to improve the measurement accuracy in the case when a pulse signal is superimposed on an information signal. The device contains a stroboscopic converter 1, an analog-digital converter 2, a synchronizer 3, a divider 4 frequencies, a delay unit 5, a storage unit 6, a block 7 for detecting the maximum or minimum code, triggers 8 and 9, and a block 10 for keys. The introduction of a delay unit, a storage unit, triggers, and a key unit to the device, and the formation of new connections between the elements of the device, makes it possible to exclude from the further processing and not use the input information signal distorted partially or completely by interference. 1il, i (L in rail. G to tc "4" vl 00 00

Description

The invention relates to electrical measuring equipment and can be used in the development of high-precision phasometric devices.

The purpose of the invention is to improve the measurement accuracy in the case when a pulse signal is superimposed on the information signal, due to the fact that the input information signal, distorted partially or completely by interference, is excluded from further processing and is not used.

The drawing shows a block diagram of a digitizer for a phase meter.

The digital converter for the phase meter consists of a stroboscopic converter 1 connected to an analog-digital converter 2, a synchronizer 3 connected to a frequency divider 4, a delay unit 5, a storage unit 6, and also a sequentially connected 7 unit detecting the maximum or minimum code 8 and second 9 triggers, block 10 keys. The first and second inputs of the storage unit 6 are connected to the first and second outputs of the analog-digital converter 2, the third input of the storage unit 6 is connected to the second output of the frequency divider 4, and the output of the storage unit 6 is connected to the first input of the key unit 10. The output of the IO key block is the output of the digital converter for the phase meter.

The digital converter for the phase meter operates as follows.

The input information signal together Q is applied to it by a pulse Interference to the stroboscopic converter 1. Synchronizer 3 receives a reference voltage, and its output contains pulses with a period, where T is the period of the input signal, P is the number of reference points in one period of the input signal . The stroboscopic converter 1 quantizes the input signal over time, i.e. it selects and stores the instantaneous values of the input signal at the moment when the pulses from the output of synchronizer 3 are exposed to the time required to process the information by the analog-to-digital converter. On the first output of the analog-digital converter 2 forms 5

0

A digital code proportional to the instantaneous value of the input voltage. The digital equivalents of the instantaneous: input voltage values are signaled at the end of the conversion signal from the second output of the analog-to-digital converter into the storage unit 6 by the addresses formed by a ivibiM divider 4 frequency whose capacity is the number of points of reference R. The storage unit 6 consists of R memory cells. The bit width of each cell is equal to the bit width of the analog-digital converter 2. Thus, the codes of all samples are located in the storage unit 6. At the device output, the sample codes are received only when the keys of the key block 10 are opened. The number of keys in the block of 10 keys is equal to the size of the analog-digital converter 2, i.e. each digit of the count code passes through its key, and all keys are controlled simultaneously. In the absence of interference, information on the output of the device passes with a delay of one period of the input signal. In the first period, the cells of the storage unit 6 are filled, and only in the next period of the input signal do the sampling codes begin to exit to the order of arrival: they are input to the storage unit 6, At the moment the code from the storage unit 6 arrives at the input of the block of 10 keys; the reference code received in the current period of the input signal is recorded in the same cell. Impulse interference imposed on the signal distorts the value of the reference code from the output of the analog-digital converter 2. The input signal amplitude should not exceed a certain threshold Un, which is less than the maximum amplitude characteristic of the analog-digital converter 2. Then the appearance criterion impulse noise and its distortion of the input signal is the appearance of the maximum (or minimum) code values. The fact of the occurrence of one of these values (the threshold is exceeded) is detected by block 7 of the maximum or minimum code detection and is remembered by the first trigger 8. Thus, the first trigger 8 detects the fact that the input signal is distorted by impulse noise. Second trigger 9

0

five

0

controls the operation of the key block 10. If in the past period there were no distortions, then the second trigger 9 is in the position allowing the operation of the keys in the block of 10 keys. If there was at least one distortion, then at the end of the period of the input signal, the pulse from the output of the 4 frequency separator will trigger the second trigger 9 into the state prohibiting the operation of the keys. In this state, the second trigger 9 is before the end of the newly started period. Setting the first trigger 8 to the zero state is made somewhat later than a census of its state to the second trigger 9. This is provided by the delay unit 5.

Thus, the periods of the input signal, completely or partially affected by impulse noise, are not used in further work, which leads to an increase in the measurement accuracy,

The error of the prototype in the considered case can be estimated in the following way.

Imagine the input signal as

S (f) U sir (t t + tfc) + + Z U.sin (ia) -t + q);)

i "

(one)

where the first term is the input information signal of amplitude U, frequency "and phase Cf, and the second is impulse noise consisting of r harmonics of frequency Sch, amplitude U, with corresponding phases cf, -. With (1), we can speak about the defeat of each K-th period of the input signal by impulse noise.

Since the measurement time is limited to targets by the number-periods of the input signal T Z 2 tt / U (Z 1,2,3 ...), the measurement result

H-ggo (2)

where Cfj is the phase shift calculated in the J-OM period of the input signal.

In the absence of impulse noise, the sequence cfj () is a statically homogeneous sequence of random numbers with a mean cf. In case of impulse disturbance, m periods in the sequence

m numbers of outliers appear (from a discrete random process tf-. Then (2). can be written as:

j Z-m I i, Ml

 Zlcf. - i: (fj + i: FED. J P.O. J I 2 j o - p-0 I

Here, the outlier value is represented by the & mm number belonging to (Q statically homogeneous population, and random increments ds. Measurement error:

(

15

....

To approximate the estimate of the maximum error, we put:

 Chr „-Why, Then

A. „, I 360 °

(3)

in the proposed digital converter for the phase meter, the lesion period is excluded from further processing. The considered error is excluded for dl and ,, and,

where and ... is the height of the interference pulse.

For Uy Uq, the proposed basic device and the prototype are equivalent. The amplitude of the signal Uj is always less than the threshold and „, i.e. . At low values of broadband noise

It is easy to ensure such values of DO at which the proposed measurement device does not exceed 1. Considering the most unfavorable case

we get that the proposed device is more efficient than the prototype, / / i (p 180 times.

Claims (1)

Invention Formula A digital converter for a phase meter containing a stroboscopic converter connected to an analog-digital converter and an information signal input, a series-connected synchronic, whose input is connected to the reference signal input, and a frequency divider that differs in order to improve the measurement accuracy, it is equipped with a delay unit, a storage unit, a sequential-connected detection unit of the maximum or a miniature code, a first trigger, a second trigger, a key block, the first and second inputs of the storage unit being connected to the first and the second output of the analog-digital converter, the third input of the storage unit - to the second output of the divider frequency, and the output of the memory block frequency through the delay block. Editor A.Revin Order 1947/45 Compiled by V.Shubin Tehred N. Bonkalo Proof E Circulation 728 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/3 Production and printing company, Uzhgorod, st. Design, 4. , ka - to the first input of the key block, the input block of the detection of the maximum or minimum code is connected to the first 5 output of the analog-digital converter, while the second input of the second trigger is connected to the first output of the frequency divider, and the second input of the first trigger - to the first high Decorrector E.Sirohman