RU2154279C1 - Device for checking nonlinear distortions of radio components - Google Patents

Abstract

FIELD: testing radio components during their manufacture. SUBSTANCE: device has sine-wave voltage generator 1, radio component 2, first band filter 3, rejection filter 4, second band filter 5, first and second adders 6 and 7, respectively, change-over switch 8 incorporating first comparator 9 and controlled-gain member 10, reference-voltage supply 11, RMS-to-DC voltage changer 12, second comparator 13. EFFECT: improved selectivity and precision of check. 1 dwg

Description

 The invention relates to microminiaturization and technology of electronic equipment and can be used to control manufactured radioelements, taking into account their non-linear distortions.

 Known meter of nonlinear distortion / Auth. testimonial. USSR N 1267282, class G 01 R 23/20, 11/30/1986, Bull. N 40 /, containing a band-pass and two barrier filters, an adder, a switch consisting of a comparator and an element with a controlled transmission coefficient, and a quadratic voltmeter.

 The disadvantages of the meter are low selectivity and accuracy, due to the low signal to noise ratio at the input of the second trap filter.

 Also known non-linear distortion meter / Auth. testimonial. USSR N 1307376, - prototype, class. G 01 R 23/20, 04/30/08, Bull. N 16 /, containing a bandpass and two barrier filters, two adders, a switch consisting of a comparator and an element with a controlled transmission coefficient, and a quadratic voltmeter.

 The disadvantages of the meter are low selectivity and accuracy, due to the low signal to noise ratio at the input of the second trap filter.

 The proposed technical solution has the task of increasing the selectivity and accuracy of monitoring non-linear distortions of radio elements.

 The problem is solved in that in the device for monitoring nonlinear distortions of radio elements, containing a sinusoidal voltage generator and a radio element connected to its output, a first bandpass filter, a first adder and a first comparator, also a blocking filter, a second adder, an element with a controlled transmission coefficient, are connected in series and a rms to dc converter, wherein the inputs of the first band and trap filters are combined and connected are connected to the junction point of the sinusoidal voltage generator and the radio element, and the output of the first comparator is connected to the control input of the element with a controlled transmission coefficient, the new one is that a second bandpass filter is added to it, the input of which is connected to the output of the blocking filter, and the output to the second the inputs of the first and second adders, as well as a series-connected reference voltage source and a second comparator, the second input of which is connected to the output of the RMS converter DC voltage, and the output to the output terminal of the device.

The use of a second band-pass filter in the device circuit (instead of a blocking one) allows you to more accurately eliminate methodological errors in measuring the first and highest harmonics. This is due to the fact that for the band-pass filter, the first harmonic is the extracted part of the input signal, the amplitude (V ₁ ) of which is large, and the suppressed part is the higher harmonics, whose amplitudes (V _i ) are small. For a trap, on the contrary, the higher harmonics are the highlighted part of the same input signal, and the first harmonic is the suppressed part.

 Thus, the blocking filter operates under conditions of strong interference (first harmonic) and a weak useful signal (higher harmonics) at its input, i.e., it has a low signal to noise ratio at the input. To work in such conditions require more sophisticated filters.

 The band-pass filter operates under conditions of a strong useful signal (first harmonic) and low noise (higher harmonics), i.e., it has a high signal-to-noise ratio at the input, which eliminates the need for special requirements for the filter and determines its advantages.

 In addition, the introduction of a second comparator and a voltage reference into the circuit of the device can increase accuracy and automate the control process.

 The drawing shows a block diagram of the proposed device.

 The device comprises a sinusoidal voltage generator 1, a radio element 2, a first bandpass filter 3, a blocking filter 4, a second bandpass filter 5, a first 6 and a second 7 adders, a switch 8 consisting of a first comparator 9 and an element with a controlled transmission coefficient 10, a reference voltage source 11, a rms to dc converter 12, a second comparator 13.

 The circuit is connected in series: the first band-pass filter 3, the first adder 6, the first comparator 9, as well as the blocking filter 4, the second adder 7, an element with a controlled transmission coefficient 10, a rms to DC converter 12 and a second comparator 13. To the generator output sinusoidal voltage 1 is connected to the radio element 2, as well as the inputs of the first band 3 and 4 blocking filters. The second band-pass filter 5 is connected by its input to the output of the blocking filter 4, and the output to the second (inverse) inputs of the first 6 and second 7 adders. The output of the first comparator 9 is connected to the control input of the element with a controlled transmission coefficient 10. The second input of the second comparator 13 is connected to the output of the reference voltage source 11, and its output is connected to the output terminal of the device.

The device for monitoring non-linear distortion of radio elements works as follows:
A sinusoidal voltage generator 1, which incorporates a load matching circuit (for example, a voltage follower on an operational amplifier), generates a signal that is fed to radio element 2.

 The studied signal is removed from the radio element 2 and fed to the first band-pass filter 3 and the blocking filter 4.

,
где γ - уровень подавления фильтра;
V₁ - амплитуда первой гармоники, частота которой совпадает с частотой синусоидального генератора;
V_i - амплитуды высших гармоник, присутствующих в выходном напряжении радиоэлемента.The output of the first bandpass filter 3 will be a signal

,
where γ is the level of filter suppression;
V ₁ - the amplitude of the first harmonic, the frequency of which coincides with the frequency of the sinusoidal generator;
V _i - the amplitudes of the higher harmonics present in the output voltage of the radio element.

.The output of the blocking filter 4 will be a signal

.

.It passes through the second bandpass filter 5, the output of which will be a signal

.

 This signal is fed to the inverse inputs of the first and second adders 6 and 7 and is added in antiphase to the aforementioned signals.

The output of the first adder 6 will be a signal
(1-γ) V ₁ .

.The output of the second adder 7 will be a signal

.

The supply of the first signal and normalization of the second signal relative to it, performed using the first comparator 9 and the element with a controlled transmission coefficient 10 (switch c), allows you to get V _i / V ₁ . From the output of element 10, a signal containing normalized higher harmonics is fed to the input of the converter 12.

.The rms to dc voltage converter 12 (constructed, for example, based on a quadratic voltmeter) performs squaring, averaging, and extracting the square root from the averaging results, as well as converting the latter to a dc voltage proportional to

.

 The comparator 13 compares this voltage with the constant voltage of the reference voltage source 11, which is associated with an acceptable level of non-linear distortion of the radio element 2. If the current non-linear distortion coefficient is less than the acceptable, a logical "0" is generated at the input of the comparator, otherwise a logical "1".

Claims (1)

 A non-linear distortion control device for radioelements, comprising a sinusoidal voltage generator and a radioelement connected to its output, serially connected to a first bandpass filter, a first adder and a first comparator, also to a series-connected trap filter, a second adder, an element with a controlled transmission coefficient and a rms to DC converter voltage, while the inputs of the first bandpass and trap filters are combined and connected to the connection point of the gene a sinusoidal voltage generator and a radio element, and the output of the first comparator is connected to the control input of the element with a controlled transmission coefficient, characterized in that a second bandpass filter is inserted into it, the input of which is connected to the output of the blocking filter, and the output to the second (inverse) inputs of the first and the second adders, as well as a series-connected reference voltage source and a second comparator, the second input of which is connected to the output of the rms to dc converter and the output goes to the output terminal of the device.