SU511675A1 - Device for automatically regulating low-frequency signal levels - Google Patents

Description

one

The invention relates to ectrospecting and can be used to transmit cra-Harioii broadcast and sound resistance of a television.

A device for automatic control of low-frequency signal levels is known, which contains an adjustable element in the main channel and an adjustable element in the control channel. rectifier with low pass filter (low pass filter) at the output.

However, the known device is very difficult due to the fact that it includes elements that are difficult to fabricate and set up, because they are subject to strict requirements of j5 for this parameter spread.

The aim of the invention is to simplify the device.

To do this, an adder is connected to the rectifier input, to one of the inputs of which 20 a signal is fed through a high-pass filter (LPF), and to the second - through a series-connected additional low-pass filter and two units for transposing the spectrum with a banded filter at the output of each.

The invention is illustrated in the drawings.

FIG. 1 shows the structural electric. Comb device diagram: in FIG. 2 - diagrams of spectra.

The device for automatic control of low-frequency signal levels contains in the main channel an adjustable element 1, and in the control channel - series-connected adder 2, rectifier 3 with low-pass filter 4 at the output. One of the inputs of the adder 2 is connected to the input of the adjustable element 1 via the HPF 5, and the other input through the series-connected additional low-pass filter 6, and blocks 7, 8 for transporting the spectrum with bandpass filters 9, 10, respectively, at the output of each. The output of the low-pass filter 4 is connected to the control input of the adjustable element 1, the output of which is the output of the device.

The device works as follows. A signal having a spectrum with lower and upper limiting frequencies F. Y (cm

nv

FIG. 2, a) is applied to parallel-connected at input 5 of the low-pass filter 5 to the low-pass filter 6, the frequency is selected approximately for the source signal. Signal

from the output of the low-pass filter 5 (see fig.) is fed to the input of the adder 2, and the signal from the output of the low-pass filter g 6 (see fig. 2jB) is fed to the input of the unit 7 for transporting the spectrum. The signal from the output of block 7 (Fig. 2, d) is fed to the input of a band-pass filter 9, which separates the upper side signal and suppresses the rest of the carrier signal and the lower side signal.

Therefore, at the output of the band-pass filter 9 a signal acts (see Fig. 2.6). This signal is then fed to the input of the block 15–8 and further to the bandpass filter U, which separates the upper side signal (see Fig. 2, e) from the carrier J (see fkg. 2, g).

The signals from the HPF 5 and bandpass filter 10 are summed in adder 2, s

the output of which is a signal with a spectrum (see

FIG. 2, h) goes to the rectifier 3 and through the low-pass filter 4 to the adjustable element 1.

Thus, the device allows the dynamic range of audio signal levels to be converted with a small non-linear distortion.

Claims (1)

Invention Formula A device for automatically controlling the levels of low-frequency signals, containing an adjustable element in the main channel, and in the control channel a rectifier with a low-pass filter at the output, characterized in that, in order to simplify the device, an adder is connected to the output of the amplifier; the inputs of which the signal is fed through a high-pass filter, and to the second through a series-connected additional low-pass filter, and two blocks for trans 20 sports spectrum with a bandpass filter at the output of each. -op  fl 2 l FIG. g