RU1797166C - Device for protection against impulse noises - Google Patents

Abstract

Usage: radio engineering, analog signal processing systems. SUMMARY OF THE INVENTION An impulse noise protection device comprises a subtractor 1, a two-way limiter 2, an electronic switch 3, an integration element 4, an adder 5 and an element for comparing the signal module with a threshold level 6. An increase in the noise immunity is achieved in the device since at the moment of pulse interference, the output signal of the device remains at the TBM level that was in the device until the moment of the appearance of pulse interference. 2 ill.

Description

With

WITH

FIG. 1

-NJ Yu XI

ABOUT

ABOUT

The invention relates to radio engineering and can be used in analog signal processing systems.

An object of the invention is to increase noise immunity.

In FIG. 1 is a structural electrical diagram of a surge protection device. In FIG. 2 is a timing chart illustrating a waveform at various points of the device.

The impulse noise protection device comprises a subtractor 1, a two-way limiter 2, an electronic switch 3, an integration element 4, an adder 5 and an element 6 for comparing the signal module with a threshold level.

The protection device from impulse noise works as follows.

The input signal X (t) is supplied to the input of the subtractor 1, where the output signal Y (t) of the integration element 4 is subtracted from it and the resulting difference

Ј (t) X (t) -Y (t)

fed to the inputs of the double-sided limiter 2 and element 6.

Two-way limiter 2 generates a signal y (t) in accordance with the equation

(Ј (1) for I E (t) l A

y (t)

Asign Ј (t) npH | e (t), where A is the restriction threshold.

The signal y (t) is supplied to the signal input of the electronic key 3 and to the second input of the adder 5, the first input of which receives the signal Y (t) from the output of the integration element 4.

Element 6 generates a signal, under the action of which the electronic key 3 is closed, if the condition

IE (t) l B,. and open if the condition is met

IE (t) I B, where B is the threshold level of element 6.

Through the electronic switch 3, which closes when the condition | Ј (t) l B is fulfilled, the signal y (t) is supplied to the input of the integration element 4.

The output of the adder 5 generates the output signal of the device, defined by the equality

Z (tH / (t) + y (t)

In the absence of pulsed interference, the mismatch signal e (t) satisfies the condition

IE (t)

in this case, the two-way limiter 2 operates in a linear mode, the electronic switch 3 is closed and the transfer function of the device is identically equal to 1, the output z (t) signal of the device exactly resets the input X (t), that is, the following equality holds: Z (t) X (t)

If an impulse noise is present in the input signal (Fig. 2a), then the error signal Ј (t) at the output of subtractor 1 satisfies the condition

IE (t) I.

In this case, the two-way limiter 2 operates in the restriction mode (Fig.2b), the electronic switch 3 is open, a zero signal is input to the integration element 4, and a level A signal is received at the second input of the adder 5. As a result

the output signal Y (t) of the integrator (Fig. 2c) and the output signal Z (t) (Fig. 2d) of the device are frozen at levels immediately preceding the moment of identification of the pulsed noise, i.e.

moment of condition

le (t) l-B.

In those cases when the behavior of the input signal (in terms of its rate of change) takes an intermediate position

between the absence and presence of impulse noise, a compromise decision is made: when the electronic key 3 is closed, the input of the integration element 4 and the second input of the adder 5 receive a signal of a limited level AsigbJE (t), since in these cases the condition is satisfied: A E ( t) B

The action of a limited signal at the input of the integrator fixes the maximum rate of change of the output signal Y (t) of the integrator and. output signal Z (t) of the device.

Thus, in the device when exposed to pulsed noise at the moment

identification of interference freezes the signal levels at both inputs, and therefore at the output of the adder 5.

Claims (1)

SUMMARY OF THE INVENTION An impulse noise protection device comprising a subtractor connected in series, the summing input of which is the input of the device, a two-way limiter, an electronic key, an integration element, the output of which is connected to the subtracting input of the subtractor, and an adder, the output of which is the output of the device, as well as an element comparing the signal module with a threshold level, the input and output of which are connected respectively to the output of the subtractor and to the control input of the electronic key, characterized in that, in order to increase the noise immunity, the other input of the adder is connected to two-way limiter output.