SU1374365A1 - Transformer-less voltage converter of radio receiver power supply unit - Google Patents

Abstract

The invention relates to electrical engineering and reduces the level of interference. The device contains rr 2 rectangular pulses, 3 power, doubler 4 voltage. Low frequency 1, band-pass filter 5 with a center tuning frequency equal to the generation frequency of g-1, trigger 6 with a common start, expander 7, comparator 8, amplitude modulator 9 were reintroduced. RF voltage is generated at a frequency fj. Mr-2 can change frequency from f to f under the influence of a control signal. Mr. 1 serves to create a harmonic. voltage of 7 ... 8 Hz. Comparator 8 allows you to set the device's sensitivity to spurious interference and to ensure a quick change in its output level. It ensures the reliability of the trigger 6. It automatically provides the transition of Mr. 2 to the standby frequency when interference occurs in the radio reception channel and is complete, its elimination 2 or less. at

Description

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 The invention relates to electrical engineering, namely to secondary power sources, and can be used as part of radio receivers.

The purpose of the invention is to reduce the level of interference from radio reception.

Fig. 1 shows a structural electrical circuit of a transformerless converter of a power source of a radio receiver; Fig. 2 shows voltage diagrams for the operation of the transformerless voltage converter for the power source of the radio receiver.

The transformerless voltage converter of the power source of the radio receiver contains a low-frequency generator 1, a generator of 2 rectangular pulses, a power amplifier 3, a voltage doubler 4, a band-pass filter 5 with a central tuning frequency equal to the generation frequency of the low-frequency generator, trigger 6 with a common start, lg driver 7, comparator 8j amplitude modulator 9.

In addition, in Fig.1 shows a radio receiver 10,

The transformerless voltage converter for the power supply of the radio works as follows.

In the generator 2, a high-frequency voltage is formed with the following frequency f, the shape of which is conventionally shown in Figure 2. The generator 2 under the influence of a control signal can change its frequency from f to f. The generator 1 serves to create a harmonic voltage of frequency 7-8 Hz (FIG. 28). Both voltages are multiplied in the amplitude modulator 9 and the amplifier 3 is supplied with a voltage, the shape of which is shown in Fig. 2 &. The presence of a low frequency component at the output of the doubler 4, from which the radio receiver 10 is directly powered, can lead to its appearance in the path of the radio receiver. Due to the choice of a small modulation factor and in connection with the usual limitation of the frequency range of the sound transmission path (20–30 Hz), as well as due to the weak sensitivity of hearing to the low frequency components of the spectrum, the signal with a frequency of 7–8 Hz is hardly observed. At the same time, if one of the harmonics of the repetition frequency causes the appearance of interference interference at the output of the radio receiver 10, then there is a component with a modulation frequency of 7-8 Hz in this interference. It is separated by a bandpass filter 5,

tuned to this frequency, and is rectified: by the trip 7. The obtained DC voltage is applied to the input of the comparator 8. In the absence of a low-frequency signal at the input of the band-pass filter 5, the comparator 8 is in a stable state determined by supplying its reference input constant voltage. The magnitude of the reference voltage determines

The sensitivity of the comparator 8 to the control signal at the input and can be selected taking into account the constantly present frequency penetration of 7-8 Hz along the power supply circuits and electromagnetic interference from the power supply unit over the field. As soon as the signal level from the terminal 7 exceeds the level of the reference voltage, the comparator 8 changes to another steady state. This causes triggering of trigger 6 and changing the frequency of oscillator 2. The presence of comparator 8 is necessary, since it allows you to set the sensitivity of the transformerless transistor

the generator to the parasitic interference, as well as providing a quick change in its output level, ensures the reliability of trigger 6, since in its absence the time required for the formation of the signal at the output of the edge 7 leads to a blurring of the leading edge of the control pulse and a decrease in the likelihood of triggering trigger 6.

When the oscillator 2 frequency changes, the position of the harmonics in the parasitic radiation spectrum changes, the parasitic harmonic no longer coincides with the frequency of the station being received, and the interference disappears when tuned to this station. As a result, 7-8 Hz at the input of the bandpass filter 5 and the comparator 8 disappears. returns to its original state. With

In this case, the state of the trigger 6, which responds only to the leading edge of the control pulse, remains unchanged, and the generator 2 continues to operate at the new frequency. If now

When tuning into a new station, interference appears, associated with the harmonics of the new pulse frequency, the whole process repeats first and causes trigger 6 to return to the initial state. As a result, generator 2 returns to the original repetition frequency, at which the interference interference disappears at the new reception frequency; In this way, an automatic transfer of the square-pulse generator 2 to the standby frequency is ensured when an interference noise appears in the radio reception channel and thereby eliminates it completely.

Claims (1)

Invention Formula A transformerless voltage converter of the power source of the radio receiver, containing a square pulse generator and connected in series with the power source and the voltage doubler, the output 0 5 0 five which is the output of a transformerless voltage converter of the power supply of the radio receiver, characterized in that, in order to reduce the level of interference from the radio, a low-frequency generator, an amplitude modulator whose modulated signal input is connected to the output of the square-wave pulse generator, is inputted to it The modulating signal is connected to the output of a low-frequency generator, and the output is connected to the output of a power amplifier, connected in series with a band-pass filter, whose input is The output of the radio receiver, a rectifier, a comparator and a trigger with a common start, the output of which is connected to the control input of the tuning frequency of the square pulse generator, and the central tuning frequency of the bandpass filter is equal to the frequency of the low frequency generator.