RU2541143C1 - Digital generator of subsonic frequency - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: digital generator of subsonic frequency comprises a close pulse generator, connected to an inlet of a binary counter, the outlet of the senior bit of which is connected to a control inlet of a polarity switch, two transformers with secondary sectional windings, connected in series via switching keys, outlets of the binary counter are connected to control inlets of the secondary sectional windings of the first transformer, and control inlets of keys of the second transformer are connected to inverse outlets of the counter, the primary inlet of the first transformer is connected to a source of AC voltage of grid frequency, and the outlet of the second transformer is connected via a rectifier with the main inlet of the polarity switch and the load.

EFFECT: production of an output signal of subsonic frequency of high capacity.

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Description

The invention relates to digital measuring equipment and can be widely used in automatic control systems and measuring equipment.

Known digital generators infra-low frequency (TsGINCH) [1-4].

However, they are made on resistors and cannot provide any noticeable power. Amplification of the output signal by power meets certain difficulties.

The closest in technical essence is TsGINCH [1], the principle of which is based on the formation of two half-waves of sinusoidal voltage by means of series-connected controlled voltage dividers also on resistors.

The use of such devices on resistors is limited by the low output power of the infra-low frequency.

The objective of the invention is to provide a digital generator of infra-low frequency high power.

The required technical result is achieved by the fact that in the proposed digital low-frequency generator the industrial frequency is used as the carrier frequency (for example, 50 Hz or any other network frequency), two transformers with secondary sectional windings of almost any required power are introduced.

The digital low-frequency generator contains a clock pulse generator connected to the input of a binary counter, the high-order output of which is connected to the control input of the polarity switch, two transformers with sectional windings connected in series, and the remaining counter outputs via switching keys (K ₀ , K ₁ , ... K _n-2 ) are connected to the control inputs of the secondary sectional windings “1” of the first transformer, and the control inputs of the second transformer are connected to the inverse inputs of the same switch key “0”, the primary input of the first transformer is connected to an AC voltage source, the primary input of the second transformer is connected to the output of the first transformer, and the output of the second is connected through the rectifier to the main input of the polarity switch and the load.

The invention is illustrated in the drawing, where figure 1 shows a variant of the construction TsGINCH on transformers, which contains:

1 - clock generator;

2 - binary counter;

3 - a source of a reference alternating voltage of a network frequency;

4 - transformer with sectional windings T1;

5 - transformer with sectional windings T2;

6 - polarity switch with switching keys (K ₀ , K ₁ , ... K _n-2 , K _n-1 );

7 - rectifier;

8 - key of the last digit of the counter;

9 - load.

The generator operates as follows (explanations are given using additional figures 2 and 3).

When the clock pulse generator 1 is started, the binary counter 2 starts working. The signals from the counter 2 go to the polarity switch with switching keys 6, switching the output (K ₀ , K ₁ , ... K _n-2 , K _n-1 ) windings of the controlled transformers 4, 5. The number of turns in the sections is subordinated to the binary code, forming a parabola section on the load 9. This happens as follows.

When filling counter 2 in the control system of such a central oscillator, at the output of the first transformer 4 (T1), a linearly increasing (step-shaped) envelope of alternating voltage is observed, and at the output of the other 5 (T2), it decreases linearly. The series connection of these transformers allows you to get the final voltage envelope in the form of a parabola section (as you know, the product of two linear functions gives a parabola). This section can be used after rectification as a half-wave of a sinusoidal voltage (figure 2).

The second half of the output signal is obtained by inverting the output 8 (using the switching key K _n-1 ). Higher odd harmonics of the periodic function (parabola) decrease in proportion to the cube of the number of harmonics, and their accounting (inclusive to ninth harmonic) provides a non-sinusoidal distortion factor K _audio envelope ≅3,8%, which is acceptable for practical purposes.

When the meter is completely full, the output voltage period ends, the next period is formed when it is filled again. The output windings of the transformers are partitioned by the number of turns obeying the binary code (figure 3).

The number of sections is determined by the required permissible discreteness error. The rectifier 7 at the output of the second transformer 5 allows you to exclude the carrier frequency and smooth the stepping of the output signal.

The control system of such a central oscillator is extremely simple, consisting entirely of a clock 1 and a binary counter 2, each bit of which, with the exception of the last one, controls the state of switching on of the corresponding section in both transformers 4, 5. The last bit of the counter using a switching key K _{n- 1} switches the polarity of the signals 8 at the output of the rectifier 7 and, thus, a full sine wave is formed. The role of controlled keys can be performed by symmistors or a pair of thyristors, connected in parallel and counter.

The efficiency of the generator is determined by the losses in the transformers, keys and in the rectifier.

Information sources

1. USSR Copyright Certificate No. 3888348, 1973.

2. Copyright certificate of the USSR No. 511681, 1976.

3. Copyright certificate of the USSR No. 538480, 1977.

4. Copyright certificate of the USSR No. 944089, 1982.

Claims (1)

A digital low-frequency generator containing a clock generator connected to the input of a binary counter, the high-order output of which is connected to the control input of the polarity switch, characterized in that two transformers with secondary sectional windings connected in series through the switching keys are inserted into it, the remaining outputs the counter is connected to the control inputs of the switching keys of the secondary sectional windings of the first transformer, and the control inputs of the switching lyuchey second transformer connected to the inverted inputs of a counter input of the first primary of the transformer is connected to a source of AC line frequency, the first input of the second transformer is connected to the output of the first transformer and a second output connected via a rectifier to the main input polarity switch and the load.

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