SU926604A1 - Digital phase meter - Google Patents

Description

{5t) DIGITAL PHASOMETER

:; ,, l, - .., ;; The invention relates to an electrical measuring technique and can be used in the construction of digital phase meters of increased accuracy. Digital phase meters are known that transform a phase shift into a digital code for an integer number of periods of the signal under study, containing a counter forming device, element And, and a quantizing pulse generator, the output of which is connected to the first input of element And, the second input of which is connected to the output of the formative device and the output to the counter input tl .: A disadvantage of the known digital phase meters is the large value of the quantization error and the error due to the effect of random noise. A digital phase meter is known that contains a feHepaTop quantizing pulses, a time driver unit, two AND elements, a time shift selection unit, a shift sign determining unit, and two INPUT shapers whose outputs are connected to the inputs of the character definition unit and the time shift selection unit, the output of which is connected to one from the inputs of the first element And, the second input of which is connected to the output of the generator of quantizing pulses and the input time of the master unit, and the output - to the first input of the second element And, the second input of which is connected to the output This is the time of the master unit, and the output is with the counting input of the summing pulse counter 2. The disadvantage of this digital phase meter is its low accuracy at low signal-to-noise ratios. The purpose of the invention is to improve accuracy. The goal is achieved by the fact that a digital phase meter containing a quantizing pulse generator, the output of which is connected to the first input of the first element I and the input time of the master unit, the output of which is under the key to the first input of the second element I, the second input of which is connected to the output of the first And, the second input of which is connected to the output of the time shift selection block, the first and second inputs of which are connected respectively to the first and second inputs of the shift sign determining block and the outputs of the first and second forms The reversible counter, one-shot, trigger and equivalence element are entered into the inputs of the phase meter inputs, the first input of the equivalence element is connected to the trigger output, the second input is connected to the output of the shift sign detecting unit, and the output of the reverse counter operating mode control , the counting input of which is connected to the output of the second element I, and the transfer output through the one-shot is connected to the inputs of parallel recording of the counter code and the input of the trigger pa:

The drawing shows a block diagram of a digital phase meter,

I

The formers 1 and 2 are connected to the inputs of the shift sign determining unit 3 and the time shift selection unit 4, and the output of the latter is connected to one of the inputs of AND 5, whose output is connected to one of the inputs of AND 6, and the second input to the output of generator 7 and input time master unit 8, the output of which is connected to the second input element And 6.

The output of the trigger 9 is connected to one of the inputs of the equivalence element 10, the second input of which is connected to the output of the shift sign determining unit 3, and the output to the control input of the reversible counter 11, the counting input of which is connected to the output of the And 6 element, and the transfer output to the input of the one-shot 12, the output of which is connected to the write inputs of the reversible counter 11 and the input of the trigger 9.

Phase meter works as follows.

The input signals are fed to the inputs of the formers 1 and 2, which convert signals of any shape into rectangular ones, fixing the moments of positive and negative zero transitions. Block 4 generates pulses equal to the time shift between both positive and negative - zero transitions of the signals generated, and block 3 determines the sign of this shift. Element And 5 provides the quantization of the selected time shifts of the pulses of the generator 7. The time of the master unit 8 at a time equal to

measurement time, opens the element And 6, and the pulses from the output of the element And 5 arrive at the counting input of the reversible counter 11.

Reversible counter 11 can operate in two modes (addition and subtraction), depending on the sign of the result accumulated in the counter, generated by the trigger 9, and the sign of the next selected temporary

shear formed by block 3.

The mode of operation of the counter 11 is established by the equivalence element 10 as follows:

a) addition, if the signs of the accumulated result and the selected time shift are the same {+, + or -,

-);

b) subtraction, if the signs of the accumulated result and the selected time shift are different (+, - or -, +).

If a transfer pulse appears in the subtraction mode at the output of counter 11, then a single vibrator 12 is triggered, which writes the unit to the least significant bit and zeros to the remaining bits of the counter, and also changes to the opposite state of the trigger 9. Change of state No trigger 9 switches counter 11 to addition mode.

Thus, the counter 11 constantly determines the absolute value of the result, and the trigger 9 forms its sign.

The positive effect of the proposed digital phase meter is to improve the accuracy at low signal-to-noise ratios.

In the proposed phase meter, when averaging the result, the sign of the time shifts is taken into account, which leads to increased accuracy.

Claims (2)

Invention Formula A digital phase meter containing a quantizing pulse generator, the output of which is connected to the first input 5.9 of the first element I and the input time of the master unit, the output of which is connected to the first input of the second element And, the second input of which is connected to the output of the first element And, the second input of which is connected to the output a time shift allocation unit, the first and second inputs of which are connected respectively to the first and second inputs of the shift sign determining unit and the outputs of the first and second drivers, whose inputs are inputs and a phase meter, distinguishing with the fact that, in order to increase accuracy, it introduced a reversible counter, monostable multivibrator, the trigger and equivalence element, wherein the first input member is equal to + valence connected to the output latch, the second input - to the output unit. determining the sign of the shift, and the output to the control input of the reversible counter operation mode, the counting input of which is connected to the output of the second element I, and the transfer output through the one-shot is connected to the inputs of parallel recording of the counter code and the trigger input. . Sources of information taken into account in the examination 1. USSR author's certificate number i (02827, class G 01 R 25/08, 1973. 2.Glinchenko A.S. et al. Digital methods for measuring phase shift, Novosibirsk. Science, 1979, p.28-2.