SU690408A1 - Digital arrangement for optimum measuring of signal phase - Google Patents

Description

(54) DIGITAL DEVICE FOR OPTIMUM MEASUREMENT OF SIGNAL PHASE

By measuring the frequency of the input signal and when its level changes, the measurement accuracy drastically decreases.

The purpose of the present invention is to expand the frequency range and increase the reliability of the device.

This goal is achieved by the fact that a digital device for optimal measurement of the phase of a signal, a bandpass filter, a discrete argument generator, coupled with & trigonometric transducers. and if if, which in turn are connected to a multiplying device, one directly and the second through a delay line, and a trigonometric arct converter, are equipped with a digital double-integrating voltmeter whose input is connected to the output of a multiplying device, and the output with an trigonometric anet converter, and a signal input multiplying device connected to the output of the bandpass filter.

The essence of the present invention is illustrated in the accompanying drawing, which shows a schematic diagram. digital device for optimal measurement of the signal phase.

The device contains a band-pass filter 1, a multiplier device 2, a generator of 3 discrete arguments, a trigonometric transducer 4 tshts) and a trigonometric transducer 5 sobf, a line b, a digital voltmeter 7 double integration, a trigonometric transducer, 8 pfct.

The measured sigual enters on. the input of the bandpass filter 1, which makes the selection of the required frequency range; output signal S (t band-pass filter 1) It is fed to the signal input of multiplying device 2, which is, for example, a digital control attenuator. A generator of 3 discrete arguments produces a sequence of pulses with a tracking interval db, which is fed to the inputs of trigonometric converters 4 and 5. Trigonometric the converter 4 q generates a digital code Si corresponding to the value of the function n (. (L1 where T is the period of the signal under investigation. Trigonometrically, the 5 costf converter produces a digital code a, corresponding to the value of the function coe (iat +), which goes to the zergee line 6, which is a shift register, where time delays occur, output j oflHr Si and CJ from the outputs TpHfQH6Metl 4fck Sr6 of the 4e4nvf converter and delay line 6 arrive at the corresponding inputs of the multiplying device 2, in which alternate, multiplication of the measured value by the numbers SH and C takes place during time intervals equal. The output signal of the multiplying device 2 during the time t is fed to the input of the digital integrator 7 of double integration, and during the first half of the time interval fe the signal is fed to the charge input of the integrator, and the second half to the discharge input. Thus, over time, the integrator of the digital voltmeter 7 of the dual integration charge, for example, 2P

Zheniemi, 5 (P 1: 81-p (p D1)

And at that time, the discharge voltage of the voltage Ua - S (t) «| l cos, (-« At). After time C has elapsed, the integrator decays to zero with a voltage (t)) i (iat). The condition of equality of charges when recharging the capacitor of the integrator follows:

r3 (t)) dt (22; flt) dt. about i T about T

V

OR t ain φ |, с т со If time t is fixed, then during time t. A count of the number of quantized pulses of a digital voltmeter 7 of the dual integrar an will calculate the number of pulses:

(HF,%.

where MC is the nominal value selected depending on the numbering system of the trigonometric converter 8arot. The code of the output from the digital voltmeter 7 of the double integration is fed to the input of the trigonometric transducer, the output of which is the result of the measurement of the phase c) y.

Compared to the prototype, not the instantaneous value of the signal sample, but the integral value of the product of the measured signal to the digital copy code is converted into a digital code. Therefore, the speed requirement for converting the measured voltage to a digital code decreases by a factor of 1 equal to the ratio of the measurement time to the time allowed in the prototype for the conversion of an instantaneous sample into a numerical equivalent. In most practical tasks, this ratio is times. The accuracy of the integrating converters is several orders of magnitude higher than the high-speed converters of instantaneous values. In addition, the dynamic range of integrating converters (digital digital and voltmeters) ranges from millivolts to hundreds of volts with a minimum quantization level of 100 nanovolts, while the quantization stage of high-speed voltage converters to a digital code is 1-3 millivolts. Finally, it should be noted that voltage converters into digital code of an integrating type can simultaneously perform some computational operations, such as division, which is not unimportant when creating small-sized, reliable, low-cost equipment.

The present invention can be used in the construction of digital optimum phase meters, precision phase meters for measuring distorted signals.

Claims (2)

1. USSR author's certificate 459741, cl. From 01 R 25/00, 1972. five 2. USSR author's certificate 412565, cl. From 01 K to 25/08, 1972 (prototype). Sx