SU1603338A1 - Non-linear filtering device - Google Patents

Abstract

The invention relates to radio engineering and can be used in radio engineering as output stages of electric meters in the presence of alternating, asymmetrical, high-level interference. The aim of the invention is to increase the filtration efficiency and reliability of the device. The goal is achieved due to the fact that the input signal is fed to the first inputs of the scaling units (for example, potentiometers and to the input of a smoothing filter. Reference constants are supplied to the second inputs of the scaling units. The output signal of the second scaling unit goes through the corresponding scaling resistors to the collector and the base of the first key transistor, the emitter of which is connected to the output of the smoothing filter. The output signal of the first scaling unit is fed to the emitter of the second a key transistor, the base and collector of which is connected to the output of a smoothing filter through the corresponding scaling resistors, the output of which is the output of the device. 2 Il.

Description

The invention relates to radio engineering and -I can be used as an output stage of electrical meters in the presence of alternating, asymmetrical high-level interference

The purpose of the invention is to increase the filtration efficiency and reliability of the device.

Figure 1 is a schematic diagram of the device; Fig. 2 shows voltage diagrams illustrating the operation of the device.

The device contains a smoothing filter 1, the first and second scaling units 2 and 3, the second and first key transistors 4 and 5, the third, fourth, second and first scaling resistors 6-9, the first and second sources 10 and II constant voltage, potentiometers 12 and 13i resistor 14, condenser 15, common bus 16. UB, I etit input and output signals of the device; V ,, - sigso

00

with

CX)

banks at the outputs of the first and second scaling blocks ".

As scaling blocks 2 and 3, potentiometers can be used.

The device works as follows.

When serving at time t | to the input of the device of the useful signal, the Q value of which, taking into account the interference signal

exceeds the bias value of the second key transistor 5, opens and connects the first scaling resistor 9 parallel to the smoothing filter 1 О Since the time constant of parallel-connected smoothing filter 1 and the first scaling resistor 9 is much less than the time constant of the smoothing filter 1 due to the smallness of the resistance of the first scaling resistor 9, the leading edge of the useful signal passes to the output of the device without distortion 25

At time t, the difference between the input and output signals of the device becomes equal to the bias voltage V of the first transistor 5, set by the motor of the second scaling unit 3, the time of the filtering device again becomes constant time

smoothing filter 1, and interference on the output of the device does not pass

When reducing the value of the useful signal at time t,. similarly, the second key transistor 4 operates, the offset U, 40 of which is set by the slider of the potentiometer 12 of the first scaling unit 2. For the input signal U gJ (Fig 2), the offset U, is specified. The potentiometer 12 engine must be 45 less than the value And, set by the potentiometer engine 13, since the amplitude of the positive polarity of the interference signal is greater than the amplitude of the negative polarity of the interference signal.

Compared with the known device, the proposed device is simpler and more reliable, since it consists of a smaller number of elements. Using the device allows you to set different threshold of sensitivity by increasing and decreasing the value of the useful signal.

Claims (1)

In addition, the implementation of the proposed device using simple, reliable and cheap elements allows it to be widely used in various, including household, equipment almost without increasing the cost of the latter. A positive effect is achieved due to the fact that the device has more functions. number of items. Invention Formula Nonlinear filtering device containing the first scaling resistor, the first and second scaling units, the smoothing filter the first and second constant voltage sources connected by the first inputs to the common bus of the device, the first and second key transistors of the same conductivity type, the first key transistor connected to the second base by the second the output of the second scaling resistor, the second key transistor is connected to the base and collector with the first terminals of the third and fourth scaling resistors, the second you the waters of which are combined, and the first input of the first scaling unit is the device input, characterized in that, in order to increase the filtering efficiency and reliability of the device, therein the first input of the second scaling unit is connected to the first input of the first scaling unit and to the input of a smoothing filter, the second input - with the second output of the second constant voltage source, and the output - with the first terminals of the first and second scaling 1x resistors, the collector of the first key transistor is connected to the second terminal the first scaling resistor and the emitter to the output of the smoothing filter and the second output of the third scaling resistor, the second input of the first scaling unit is connected to the second output of the first constant voltage source, and the output to the emitter of the second key transistor, and the output of the smoothing filter is device output