SU564606A1 - Harmonic distortion factor meter - Google Patents

Description

(54) METER. HARMONIC COEFFICIENT

one

The invention relates to a series of electrical techniques, can be used to measure the harmonic coefficient of radiation).

A digital measure of the distortion coefficient is known, containing anapog converters connected in a certain way — a code, two kaochev schemes, two transfer blocks, a frequency multiplier, will be set: normalized harmonic IR, a multiplier and a divider of numeric codes, a calculator and a calculation block, a comparison block ..

This device is characterized by a low accuracy of measurement of small values of the nonlinear distortion coefficient.

Closest to the proposed harmonic coefficient measure: containing a driver, a frequency multiplier, an analog-to-digital converter, two setters; orthogonal functions, two multipliers, two counters, a transfer unit, a quad block, a quad, an adder, a root extraction device, a code ratio meter and an L2J control block,

However, this device also has a low coefficient of measurement accuracy.

nonlinear distortion at small values of it. The latter follows on the following. It is known that modern-aj anoro digital converters make it possible to generate code values whose size does not exceed three decimal places. Consequently, the minimum value of zero from the formula

R

I

..100%,

and.

which determines the value of the nonlinear distortion factor, is 0.001. So the minimum possible value, the coefficient of nonlinear distortion is 3.3%.

I The indicated value is a quantization step of the values of the nonlinear distortion coefficient.

The purpose of the invention is to improve the accuracy of measuring the nonlinear distortion coefficient in a wide range of values - it is achieved in that the harmonic coefficient meter contains serially connected driver, frequency multiplier, cable, analogue - digital converter, quad, adder, first transfer unit, root block and the meter ratio of codes, as well as two identical chains, each of which contains a serially connected master of the orthogonal function, a multiplier block, a counter, and a block sa, the output of which is connected in parallel to the inputs of the quadrant and the code ratio meter, the second inputs of the multipliers are connected to the output of the analog-to-digital converter, the input of the setter of the orthogonal function of the first circuit is connected to the output of the key, and the counter input of the second circuit is connected to the output; the root extraction unit, two transducers, a code-voltage, a voltage subtraction unit and a scale selection unit, the output of which is connected to the second input of the analog-digital converter, as well as the initial phase setting unit, one input of which is connected to the output of the key, are inserted. the other is connected to the output of the code ratio meter, and the output is connected to the master input of the orthogonal function of the second circuit, and the first and second inputs of the second code-converter are connected to the outputs of the counter and the master and the orthogonal functions of the second circuit, and the second input of the block is read out connected to the input of the imaging unit. The drawing shows a block diagram of a harmonic coefficient meter. The device contains a shaper 1 connected in series, frequency multiplier 2, key 3, analog-digital converter 4, quadrant 5, adder 6 transfer unit 7, root extraction unit 8 meter of 9 ratio of codes, initial phase setter 1O, orthogonal function setpoint 11 , multiplying unit 12, counter 13, transfer unit 14, the output of which is connected to the second input of the quad 5 and to the second input of the ratio meter 9, the third input of which is connected to the third input of the quad 5 and to the output of the transfer unit 15, input through the meter 16, the multiplier unit 17 and the setter 18 of the orthogonal function are connected to the second input of the setter 1O and to the first input of the transducer 4, the second input of which is connected through the scale selection unit 19 to the output of the voltage subtracting unit 2O, the second input of which is connected to the input of the imager 1 and the first input is to the output of the converter 21. Od-y voltage, the second input of which is connected to the output of the sensor 11, and the first through the second converter 22 code - voltage of the second output of the counter 13, the second input of which is connected to the output of the block 8 removed Yeni roots. The input of the device is the input of the former 1, and the output is the output of the meter 9. The meter also includes a control unit 23, which synchronizes the operation of the circuit in time. The circuits on which control signals are transmitted are not shown in the drawing. The device operates as follows. In the initial position, all the counters and adders are located in. zero state} to the first input of the voltage subtracting unit 20 the voltage U o is connected; key 3 is closed; On the setting unit 10, the initial phase is set to 0 °. The signal under study D is fed to the pulse shaper 1 and block 20. When U goes through zero, control device 23 opens key 3, and frequency multiplier 2 pulses follow 1 g pulses to converter 4 inputs, setpoint 18 and 1O, Codes instantaneous voltage values Jf the signal under study from converter 4 is sent to multiplying blocks 1-2. and .. 17, the second inputs of which synchronously receive the value of 1 orthogonal functions in digital form from setters 11 and 18. The codes of products from blocks 12 and 17, taking into account the characters, are added to counters 13 and 16, respectively. During the period of the signal under study, the counters 13 and 16 are fixed by the values of the name and the actual components of c. Fourier coefficient of the first (main) harmonic. At the end of the period, a command from block 23. of control codes from counters 13 and 16 pushes through the transfer blocks to the inputs of the quadrant 5. At the adder 6, a code is generated which passes through the transfer block 7 to the root extraction block 8, the output of which is the magnitude of the amplitude of the first harmonic 0 At the same time, the codes of values a and c come from the blocks 14, 15 to the meter 9 of the ratio of codes. At the 6noifa 9 output, an a- / c. Ratio code appears that uniquely identifies the code for the initial phase of the fundamental wave. The setter 1O assigns to the value a. (In the initial address (ordinate number) LL is orthogonal; the function generated by the setter 11. The counter 13 is set to the zero state, and then the value code p from the block 8 is written to it. the termination of the second period of the studied signaling, determined ampitude, and the beginning of the phase If, besides, when subtracting and squaring the instantaneous values of the results obtained, the value is formed, equal to the power of the highest harmonics. , obtained from the expression defining the coefficient of harmonics can be arbitrarily small. Therefore, to measure with an admissible error of 1, the target value is proposed to be amplified several times. The subtraction operation is implemented in the proposed device as follows. Converter 22 forms a voltage and KOTODoe the proportional code is the reference for the converter 21, the second input of which connects the values of the ordinate of the sinusoidal (one of the orthogonal) function. In block 20, subtraction occurs. Block 19 selects a scale (gain factor) to represent the difference such that the maximum value of the specified difference becomes comparable (but not greater) with the maximum possible input signal. During the passage of the third type of signal under test input signal harmonics by squaring the codes of the instantaneous values of the difference on quadrant 5 with the subsequent addition, the results on the adder 6. At the end of the third period of the signal under study on the adder 6 forms The value is proportional to the proportional code. Next, the code of T, .j from the adder 6 through the transfer unit 7 is fed to the input of block 8, the output voltage of which goes to the first input of block 9, the second input of which gets the code U. The output of block 9 is fixed code ut - and:

Claims (1)

Invention Formula Meter; harmonics coefficient, containing sequentially; connected driver, frequency multiplier, key, analog-digital converter, i quad, adder, first transfer unit, root extraction unit and oTHodi code meter, as well as two identical circuits, each of which contains connected setpoint orthogonal ° functions, multiplying unit, transfer loop counter, the output of which is connected to the inputs of the quad and the code ratio meter, the second inputs of the multipliers connected to the analog output - a digital converter, the input of the orthogonal function of the first circuit is connected to the output of the key, and the input of the counter of the second circuit is connected to the output of the root extraction unit, characterized in that, in order to improve the accuracy, the first and the second code-to-converter, block, block; voltage reading and scale selection block, the output of the key switch to the second input of the analog-to-digital converter, as well as the initial phase setting block, one input of which is connected to the key output, the other to the output of the meter ratio of the CODES; Its output is the input of the unit of the orthogonal function of the second circuit, the input of the first and second input, the second transducer code-voltage are connected respectively to the outputs. counter and sensor orthogonal function of the second circuit, and the second input of the subtraction unit is connected to the input form. Sources of information taken into account in the examination: 1.JAeTopCKoe USSR certificate № 470759, Q 01 R .. - 23/20, 1974. G 2, USSR Author's certificate No. 379882, Q 01 R. 23/20, 1973. : viit% ::. n irij v i  ; one