SU761931A1 - Non-linear distortion coefficient meter - Google Patents

Description

The invention relates to radio measurements, can be used to measure the coefficient of nonlinear distortion.

Known digital meter coefficient of nonlinear distortion C], which contains the converter "analog-code", divider and multiplier of numeric codes, the comparison unit, the computation unit, the setpoint regulator of harmonized harmonics, a frequency multiplier, two electronic keys and two skew circuits. Its disadvantages is the limited lower limit of measuring the nonlinear distortion factor.

Closest to the proposed harmonic coefficient meter, [2] containing a serially connected driver, frequency multiplier, key, analog-to-digital converter, quad, adder, first transfer unit, root extraction unit and code ratio meter, two identical circuits of series-connected setting device of the orthogonal function, multiplying unit, counter and transfer unit, serially connected first and second transducers “code-voltage”, block (subtracting voltages • and block selection ly, as well as the block setting the initial phase, connected in a certain way among themselves.

2

This measurer is not inherently high accuracy, limited by the need to determine the initial phase.

The purpose of the invention is to improve the measurement accuracy ^{of 5.}

This goal is achieved by the fact that the meter of nonlinear distortion, containing analog-to-digital converter, control unit, two chains, each of which contains a duplicating unit connected in series and a counter, connected in series voltage subtraction unit and a scale selector unit connected to the output an analog-to-digital converter input, a quad, connected by an input to the outputs of counters and an analog-to-digital converter, and a code divider, as well as a master orthogonal their functions, connected by their outputs to the first inputs of multiplying blocks, the second inputs of which are connected to the output of an analog-digital conversion; and two code-voltage transducers connected in series, the first of which is connected to the output of the quadrator and the second to the first output of the orthogonal functions transmitter whose input is connected to the control input of the analog-to-digital converter

761931

one nz outputs of the control unit; the input of the latter is connected to a point combining the information input of the analog-digital converter, the first input of the voltage subtraction unit and the device input, a third code-to-voltage converter and an adder are added, and a third code-to-voltage converter is connected to the potential input to the output of the first converter “code - voltage”, and the control input to the second output of the master of orthogonal functions, the outputs of the second and third converters “code to voltage” are connected by the inputs of an adder , • whose output is connected to the second input voltage subtraction unit.

The block diagram of the proposed meter shown in the drawing.

The meter contains analog-to-digital converter 1, control unit 2, voltage subtraction unit! 3, unit of orthogonal functions 4, multiplying blocks 5, 6, counters 7, 8, quad 9, divider codes 10, code-voltage converters 11, 12, 13, the sum of mountains 14 and the unit for selecting the scale 15.

The principle of operation of the device is as follows.

The signal under study is fed to the information input of the analog-digital converter 1, to the input of the control unit 2 and to the first input of the voltage subtraction unit 3. The control unit 2 is used to set the sampling points of the signal under study. And to synchronize the operation of the device. The sampling moments of the signal under study are set using the frequency multiplier contained in the control unit 2. The pulses generated by this multiplier are output from the control unit 2 to the control inputs of the analog-to-digital converter 1 I set up the orthogonal functions 4. With the arrival of these pulses, the codes of the orthogonal functions come from the setter codes of orthogonal functions 4 are fed to the first inputs of the multiplying blocks 5 and 6, respectively. The other inputs of the multiplying blocks 5, 6 receive codes of the instantaneous values of the signal under study. Codes from the outputs of the multiplying blocks 5, 6 are fed to the counters 7, 8, respectively, where they are added up taking into account the signs at the points for the period of the signal under study. As a result, codes of imaginary and real components of the first harmonic of the signal under investigation are recorded in counters 7, 8. After that, codes of the imaginary and real components are entered into the quad 9, in which the calculation of the amplitude of the signal under investigation is performed.

The code of the amplitude of the investigated signal

enters a 10n divider of codes on a code-voltage converter N. In a code-voltage converter 11, the code is transformed into a proportional constant voltage. This voltage is used as a supply voltage for code-to-voltage transducers 12, 13. The control inputs of these transducers are fed codes of orthogonal functions with a frequency determined by the frequency of the signal under study: the code from the first output of the setpoint generator of orthogonal functions 4 —to the input of the converter 12 and the code from the second output of the setter 4 - to the input of the transducer 13. At the outputs of the transducers 12, .13, sinusoidal voltages are formed. These voltages are fed to the inputs of the adder 14. The resulting voltage at the output of the adder 14 is the first harmonic of the signal under study.

The voltage from the output of the adder 14 is supplied to the second input of the voltage subtraction unit 3. At the output of the latter, a voltage equal to the sum of the instantaneous values of the higher harmonics is extracted. This voltage through the block selector scale 15, which sets the required gain, is fed to the input of an analog-to-digital converter, where it is subjected to quantization. Instant Codes. Values! . The voltages from the output of the analog-digital converter 1 are fed to the quadrant 9. At the output of the quadrant 9, a code is generated, which is fed "and a divider of codes 10. In the code 10 divider, the code of the nonlinear distortion is determined.

Claims (1)

Claim Non-linear distortion coefficient meter containing an analog-digital converter, a control unit, two chains, each of which contains a duplicating unit connected in series and a counter, a voltage subtraction unit connected in series, and a scale selector unit connected by an output to an information input of an analog-digital converter, a quadrator, connected by an input to the outputs of counters and an analog-to-digital converter, and a code divider, as well as a master of orthogonal functions, connected by its outputs to The first inputs of multiplying blocks, the second inputs of which are connected to the output of an analog-digital converter, and two serially connected code-voltage converters, the first of which is connected to the output of the quadrator and the second to the first output of the setter of orthogonal functions, whose input connected to the control input of the analog-to-digital converter and one out of the outputs of the control unit, the input of the latter is connected to the point uniting information 761931 6 input of an analog-to-digital converter, the first input-block of voltage subtraction and the input of the device, which, in order to increase the measurement accuracy, a third code-voltage converter and an adder, the third converter “(code — voltage” is connected by a potential input to the output of the first code-voltage converter, and the control input is connected to the second output of the orthogonal functions master, the outputs of the second and The third code-to-voltage transducers are connected to the inputs of the adder, the output of which is connected to the second input of the voltage subtraction unit. five