SU1368804A1 - Phase calibrator - Google Patents

Abstract

The invention relates to electrical measuring equipment. The purpose of the invention is to expand the functionality of the device. The Phase Calibrator contains a reference generator 1, a discrete phase shifter 2, an indicator 6 and a multiplexer 10. Introduction of a digital phase meter 3, a buffer operating memory 4, a dispersion calculator 5, as well as a clock pulse generator 7, a persistent memory 9 and block 11 The control allows the formation of phase fluctuations calibrated with dispersion with a given distribution law and a wide spectrum at any frequency in the operating range. The description contains examples of implementation of the dispersion calculating unit 5 and the control unit 11. 2 z.p, f-ly, 1 ill. u (L J SO a 00 00

Description

113

The invention relates to electro-radio measurements and can be used for calibrating phase fluctuation (FF) meters and phase modulation meters.

The purpose of the invention is to expand the functionality by forming phase-fluctuations calibrated with dispersion with a given distribution law and a wide spectrum at any frequency in the operating range.

The drawing shows a diagram of the phase calibrator.

The phase calibrator contains a series-connected reference generator 1 and a discrete phase shifter 2, a digital phase meter 3, a buffer operational memory (RAM) 4, a block 5 for calculating the dis

Persia, indicator 6, as well as clock generator 7, counter 8, persistent memory (ROM) 9, multiplexer 10 and control unit 11, the input and output of phase shifter 2 connected to the inputs of the phase meter 3, the output of which is connected to the information input of the buffer RAM 4, and the last output - with the RUN of the block 5, the output of which is connected to the indicator 6, the output of the generator 7 is connected to the inputs of the counter 8 and the control unit 11, the output of the counter 8 is connected to one of the inputs of the multiplexer 10 and the address input of the ROM 9, the output of the ROM 9 connected to another stroke multiplexer 10, whose output is connected to a control input of the phase shifter 2 and the address input of the buffer RAM 4. The output of the calibrator is output 2 phase shifter coupled to the measuring input power metal emogo meter 12 PF.

The calibrator also has a second output, which is the output of the generator 7, which is connected to the input of the reference signal of the meter being turned 1 2 FF.

In addition, the dispersion calculating unit 5 contains an averaging unit 13, a subtracting unit 14 and a calculator of an average square, and their control inputs are connected to the control input of block 5, one of the inputs of the subtraction unit 14 and the input of averaging unit 13 , and the output of the transmitter 15 is connected to the output of block 5, the output

the averaging unit 13 is connected to the second input of the subtracting unit 14, the output of which is connected to the input of the calculator 15.

The control unit 1 1 contains two inverters 16 and 17, two key stages 18 and 19, a delay element 20, a switch 21 and a button 22, the input of the inverter 16 is grounded, the input and the output are connected to the input contacts of the commutator 21 and the button 22, the output of which is The start output of control unit 11, the output of switch 21, which is the second control output of control unit 11, is connected directly to the control input of key stage 18, and key stage 19 through

an inverter 17, the signal inputs of both key stages are connected to the output of a delay element 20, the input of which is the input of control unit 11, the outputs of key stages

18 and 19 are respectively the third and fourth outputs of the control unit 11.

The device has two modes of operation and works in them as follows,

In mode 1, the Phaser 2 is tested at the selected operating frequency, which is set by highly stable generator 1. For this, control unit 11 resets counter 8 to O and enables counting to stop, and multiplexer 10 switches to direct transfer mode from counter 8 to control the input of the discrete phase shifter 2 and the address input of the buffer RAM 4, Considering the incoming clock pulses from the generator 7, the counter B sequentially goes through all possible states of the phase shifter 2, and then stops. Information about phase shifts introduced by phase shifter 2 is measured by phase meter 3, triggered at each cycle by a signal from control unit 11, and stored in memory cells of buffer RAM 4, the address for which is counter code 8, In mode I, control unit 11

sets buffer RAM 4 to write mode. The clock generator 7 is switched to a low pulse repetition rate sufficient to trigger the phase meter 3,

Mode II generates calibrated FFs, for which the control unit 11 switches the counter 8 to the continuous counting mode of the generator 7, and the multiplexer 10 transfers the contents of the memory cell of the ROM 9 to the control input of the discrete phase shifter 2 and the address input of the buffer RAM 4 At the same time, in the ROM there is an array of random numbers, formed in accordance with the required law of probability distribution PF. The address for the sequentially recalled memory cells of the ROM is the output code of the counter 3. Thus, at the output of the phase shifter 2, a harmonic signal with a randomly varying phase is formed, which is fed to the measuring input of the measuring meter 12 FF.

If sampler and storage devices are in meter 12, a signal from clock generator 7 is supplied to its reference input to synchronize operation of meter 12 FF and dispersion calibrator FF. Pulse frequency of generator 7 is selected from the requirements to the width of the spectrum of the generated phase fluctuations and requirements to the reference signal meter 12 FF.

Phase meter 3 is not used in mode II. The buffer RAM 4 is switched by the control unit 11 to the read mode, and information about the actual phase shifts after each clock pulse is fed to the input of the dispersion calculation unit 5. The change in the probability distribution law of the FF is carried out by a mechanical change of the ROM chip.

The dispersion calculation unit 5 calculates the unbiased estimate of the variance of a unit deviation using the known formula

N

(i) y

D

one

N-1

(one)

de D

N

  f

variance estimate; number of phase shifts processedJ

phase shift for i-ro clock pulse averaged phase shift value.

 N

.

(2)

For continuous real-time operation, block 13 performs an averaging operation for each group of last phase shifts, for convenience of the technical implementation, i N is fixed and equal to N 2, where m is integer, and formula (2) is converted to

15

H

-. (., - N-Cfi., - fCf;).

(3)

In this case, the division and multiplication operations by N are implemented by adding or discarding lower-order bits.

Deviations of the phase shift from its average value () calculated in subtraction unit 14 are sent to the average square calculator 15, which, to simplify the technical implementation, lists the variance for each clock pulse with an approximate formula derived from formula (1)

thirty

D.

D;., N-D;., + (Tf; -Cp;) (4)

35

40

45

50

55

And contains only one multiplier. Despite the approximate nature of formula (4) with sufficiently large

N, i and the stationary process of phase deviations practically obtained accuracy of calculating the estimate of dispersion is quite high (up to 1%). The current estimate of the variance of the generated phase shifts is continuously induced on the digital indicator 6.

The switching modes of the dispersion calibrator FF are performed by the switch 21 of the control unit 11, which outputs the control signal as O or 1. This signal switches multiplexer 10, buffer RAM 4 to read or write mode, counter 8 to continuous counting or counting with stopping . The start signal of control unit 11, generated by button 22, resets counter 8 before calibrating phase shifter 2, generator 7 pulses, delayed by delay element 20 of control unit 1 1 to compensate for inertia of phase shifter 2, in the certification mode of the latter, via phase switch 18, start phase meter 3 , and in the FF formation mode, the dispersion calculation unit 5 is put into operation through the key stage 19. The switching of the key stages is effected by a signal from the switch 21.

Of the known devices, the most suitable for rapid calibration of FF meters is a device containing a highly stable oscillator, a frequency modulator and a low frequency oscillator. The requirements on the reproduction accuracy of the FF with a calibrated dispersion lead to a considerable complication and increase in the cost of such a device. The introduction of a known device comprising a reference generator and a discrete phase shifter, a clock generator, a ROM, a multiplexer, a digital phase meter, a buffer RAM, a dispersion calculator, an indicator, and a control unit allows it to be used to obtain calibrated FF with a given distribution law and a wide range at any frequency of the working range, which increases the accuracy and accuracy of calibration of FF meters. At the same time, the cost of it

economic effect is achieved. In addition, the digital phase meter used in the FF dispersion calibrator circuit is used only in the discrete phase rotator certification mode, and is not used in the generation of calibrated FF operating mode, therefore it becomes possible to use one digital phase meter for a group of several calibrators.

Claims (2)

1. A phase calibrator containing a reference oscillator and a discrete phase shifter connected in series with it, the control input of which is connected to the multiplexer output, characterized in that, in order to extend the functionality by forming 3688046 calibrated by the dispersion of phase fluctuations with a given distribution law and a wide spectrum at any frequency of the operating range, a digital phase meter, a buffer operational memory, a dispersion calculation unit, an indicator, a pulse generator, a counter, a permanent memory, and a control unit have been entered into it, moreover, the input and output of the phase shifter are connected to the corresponding inputs of the phase meter, the output of which is connected to the information input of the buffer operational memory, output One of the latter is connected to the input of the dispersion calculation unit, the output of which is connected to the indicator, the output of the clock generator is connected to the inputs of the counter, the control unit and the terminal for connecting the meter to be turned, the output of the counter is connected to one of the The 25 inputs of the multiplexer and the address input of a permanent storage device whose output is connected to another input of the multiplexer, the output of the multiplexer is connected to the address 30 input buffer RAM, the output of the phase shifter Connected to the second terminal to connect the test measure 5 0 five 0 five the first output of the control unit is connected to the first control input of the counter, the second output to the second control input of the counter and the control inputs of the multiplexer and buffer random access memory, the third output to the control input of the phase meter, and the fourth to the control input the input of the dispersion calculation unit. 2. A calibrator according to claim 1, characterized in that the dispersion calculating unit comprises an averaging unit, a subtracting unit and a mean square calculator, the control inputs of which are connected to the control input of the dispersion calculating unit, one of the inputs of the subtracting unit and the input of the averaging unit are connected to the input of the dispersion calculator, and the output of the average square calculator with its output, the output of the averaging block is connected to the second input of the subtracting unit, the output of which is connected to the input of the average square calculator. 713688048 3, the Calibrator according to claim 1, about tl i-mutator connected to the second output The control and control unit for the control device contains two inverters, the twenty-first key stage of the non-key stage, the delay element, and the second through the switch and the button, the input of the inverter, the signal inputs of the first inverter are grounded, and the input stages are connected to the output it is connected to the input of the delay element, the input of which contacts of the switch and button, you are connected to the input of the control unit, the course of which is the output of the Start IQ outputs of the first and second key control unit and connected to the first cascades are connected respectively control unit output, com output with the third and fourth block outputs  management