SU1223158A1 - Apparatus for measuring signal complex enveloping harmonics - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the real and imaginary components of complex envelopes or amplitudes and initial phases of signal harmonics with time-varying parameters. The purpose of the invention is accuracy and precision. rhenium frequency range of the measured signals. The device contains a digital oscillator 1 orthogonal sinusoidal signals, auxiliary digital-analogue blocks 2 and 3 multiplication, integrators 4 and 5, a functional converter 6, a recording unit 7, a digital-analog multiplication unit 8, a frequency multiplier 9, a counter 10, a code converter 11. Digital oscillator 1, auxiliary digital-analogue blocks 2 and 3 multiplications, and integrators 4 and 5 constitute a block for selecting orthogonal sinusoidal signals. In order to achieve the goal, a counter 10 and a code converter 11 are entered into the device. 1 hp f-ly, 1 ill. I (O

Description

one

The invention relates to a measurement technique and can be used to measure the real and imaginary components of complex bendings or amplitudes and initial phases of harmonics of signals with time-varying parameters.

The purpose of the invention is to increase the accuracy and expansion of the frequency range of the measured signals.

The drawing shows a functional diagram of a device for measuring complex envelope signals.

The device contains a digital generator of 1 orthogonal sine-wave signals, auxiliary digital-analog blocks 2 and 3 multiplications, integrators 4 and 5, as well as a functional converter 6, block 7 of registration, digital-analog block 8 multiplication, multiplier 9 frequencies, counter 10 and converter code 11. The input bus device is connected to the signal input of the multiplication unit 8, the output of which is connected to the signal inputs of the auxiliary blocks 2 and 3 multiplication, the outputs of which are connected to the signal inputs of the integrators 4 and 5, the inputs of which are connected to the functional input of the block 7 registration. In addition, the device input bus is connected to the input of frequency multiplier 9, the output of which is connected to the counting input of the counter 10 and the synchronization input of the generator 1, the bit outputs of the counter 10 are connected to the inputs of the code converter 11, the strokes of which are connected to the control inputs of the multiplication unit 8 and the generator outputs are the 1st control inputs of blocks 2 and 3 multiplying. The overflow output of the counter 10 is connected to the inputs of the initial installation of the integrators 4 and 5 and the generator 1, as well as to the start input of the registration unit 7. The capacity of the counter 10 is equal to twice the value of the multiplier of the frequency multiplier 9 frequency. The code converter 11 converts the input code into an additional code, and its sign bit is connected to the output of the high bit of counter 10, Digital generator 1, auxiliary digital-analog blocks 2 and 3 multipliers, integrators 4

0

15

20

25

thirty

35

40

45

50

55

and 5 constitute a block 12 for orthogonal sinusoidal signal extraction.

The duration of one measurement cycle of the complex envelope of one of the harmonics is equal to twice the period of the first harmonic of the input signal.

The period T of the first harmonic of the input signal U (t) is divided in frequency multiplier 9 into N parts. The input pulses of the frequency multiplier 9, the period of which is equal to T / N are fed to the counting input of the counter 10, the capacity of the counter 10 is 2N, Since the most significant bit of the counter 10 is connected to the input of the sign bit of the converter 11 on odd periods of the input signal, when the state the high bit of counter 10 is zero, the code h at the input of converter 11 takes values and the N at output of converter 11 (division is done by transferring a comma), and for even periods of the input signal when the high bit of the counter equals In this case, its low-order code is converted to the (N-h) / N code at the output of the 1 1 converter.

The output codes of the generator 1 when measuring the complex envelope of the K-th harmonic of the input signal O (t) after the h-th pulse of the multiplier 9 h1 "oit are equal to .- С05 -Кп and 5in-Кп .. These

the codes arrive at the inputs of auxiliary blocks 2 and 3, respectively. The number of the measured harmonic 1 is set using the code K on the control inputs of the generator 1, the number n of the output pulse of the frequency multiplier 9 is counted from the beginning of the period.

The input signal U (i) passes through blocks B, 2 and 3 multiplied by the signal inputs of integrators 4 and 5, the integration in which takes place over two periods of the input signal. At the end of this time interval, the output signals of integrators 4 and 5, equal respectively to real a, and imaginary b components of the complex envelope of the K-th harmonic, are fed to the functional converter 6, which determines the value of the K-harmonic envelope at the current time, for example, by extracting the square root of the sum of the squares of the components qj; and b

At the end of the second period of the input signal, a signal appears at the overflow output of the counter 10, which starts the recording unit 8, and initializes the integrators 4 and 5 and the generator 1. At the same time, information on the parameters of the complex the harmonic envelope, and integrators A and 5 and generator 1 are being prepared for a new measurement cycle.

The laws of change of the harmonics Ij (t) of the input signal U C t) in the time interval - L whose duration is 2T, can be approximated by linear laws. Then in this time interval the input signal is described by the dependence

.t.o..ye, tcos (-f-Ki.,. K

(one)

where AC is the amplitude, oi is the angle of shift

the phases of the constant component of the K-th harmonic signal,

 rate of change; phase angle of the linearly varying component of the K-th harmonic of the signal.

Then the complex K-harmonic envelope in this time interval is described by a linear function

(2)

U ,, + B, i,.

Where

.

,,. A, e, B,

and the instantaneous value U (t) in the middle of the specified interval is Ux {o) 4 The duration of one measurement cycle is equal to two periods of the input signal. You can take the middle of this time interval for the beginning, counting, then the numbers of the pulses of the multiplier 9 frequencies in the first cycle of the device have negative values, and change from - N to -1, and in the second from O to (N-1) . Then the input of block 8 multiplication enters a code equal to

H (1)

(.. O - NH,

and the inputs of blocks 2 and 3 multiply the codes cos-rKp and 6 n-kn

ie

.WITH-,

i -N, ..., N-1.

The measurement results (output signals of integrators 4 and 5) are analyzed - 5. As a complex number.

(L

Then, in block 12, the orthogonal components of the input signal are multiplied by the complex coefficients

M (t) .co.fxn.js, -nf) Cn- /,

, (n + o, nn, ..., ni. (5) The input signal (1) looks like

joik iT- K -2

l -JO if -3T t -tAke e 425

.eight,

ZD

If we put

,,,

8, .u, ... About.

; then the input signal (1) takes the form

/

U (t) 45: lA, .8,

Chs - 1U

(6)

It can be shown that the value of the complex envelope in the middle of the interval is. The measurement (i.e., at the point in time that is assumed to be zero) is equal to the value of C.

Let in the input signal there is only, - one E - harmonic ggfiN JT a

L 2 2 J is measured by a Kgaromnik, i.e.

() i (, t)

In accordance with the stated principle of the device operation, the value of C is equal to

Ck-fJu (t) Het) M (t} dt. (8)

-t

After substitution (7), (3) and (5) in the expression (8) receive

with, ,

) e

f if. e cjt +

I (.0 I N: J f..,,.; W.

4r I ((th

et

Ji.

(9)

The calculation of the definite integral (9) gives,

and t

5iM-T- --n

Ck

N

e / n

O, E, i.e. measurement result depends

12231586

percent of the amplitude of the first harmonic.

Claims (2)

1. A device for measuring complex harmonic envelopes of signals, containing a digital-analogue unit of mind10 cut-outs, a frequency multiplier, two auxiliary digital-to-analog multiplication unit, the outputs of which are connected to the signal inputs of the integrators, and a digital orthogonal generator ) 5 sinusoidal signals, the outputs of which are connected to the control inputs of the auxiliary digital-analogue multiplication units, the outputs of the integrators are connected to two inputs functionally only from the value of the complex envelope 20 of the voltage converter (6) in the middle of the measurement cycle. At the same time, there are methodological amplitude and phase errors, which are characteristic of all analyzers of this type, in which M (-b) is specified as a stepwise variable function. The first error at a sufficiently large N is negligible, and the phase error can be easily eliminated by transferring the initial moment of time by the value t / 2N. Thus, the device allows to increase the accuracy, since the connection of the control inputs of the multiplication unit 8 through the code converter 11 and the counter 10 to the output of the frequency multiplier 9 ensures linearity of the change — the signal (2) H (i;), synchronized with the frequency of the input signal the synchronization of the start of block 1 at the time of the beginning of the increase in the signal HC-i) At the same time, the frequency range of the input signals expands, since duration of steps in the signal H (-t), equal to T / N is proportional to the period of the input signal. The achieved positive effect allows to measure the higher harmonics of the signal, the amplitudes of which do not exceed a fraction of Editor E. Papp 45 2. The device according to claim 1, wherein the capacity of the counter is: equal to twice the frequency multiplier factor of the frequency multiplier. Compiled by S. Lebedev Tehred I.PopovichKorrektor S.Shekmar Order 1708/48 Circulation 728 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Ra vice on b., d. 4/5 Branch P1P Patent, Uzhgorod, Proektna St., 4 connected to the signal input of the registration unit, the device input bus is connected to the synchronization input of the digital generator of orthogonal sinusoidal signals and the signal input of the digital-analog multiplication unit, the output of which is connected to the signal inputs of the auxiliary digital-analog multiplicator, characterized in that, in order to increase the measurement accuracy and expansion frequency range, a counter and a code converter are entered into it, the outputs of which are connected to the control inputs of the digital-analogue unit and multiply, and the inputs from the output digits of the counter, the counting one, whose input is connected to the output of the frequency multiplier, and the overflow output is connected to the initial setup of the integrators and the digital generator of orthogonal sinusoidal signals and the start input of the recording unit.