SU1317651A1 - Filter with switching ability - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase the signal to noise ratio. The filter contains rc 1 pulses, N frequency dividers 2, multiplexer 3, shaper (f) 4 pulses of variable duty cycle, rr 5 pseudo-random pulses, resistor 6, switch 7, capacitor 8. The pulse width f 4 is controlled by the control signal supplied to the control input F 4, which allows you to tune the cutoff frequency of the filter. 1 il.

Description

The invention relates to radio engineering and can be used in frequency selection circuits, in particular for the selection of electrical sensor signals.

The purpose of isobacetene is to increase the signal-to-noise ratio at the output of the switched filter.

The drawing shows a structural electrical circuit of the proposed switched filter.

The switched filter contains a generator of 1 pulses, N dividers of 2 frequencies, a multiplexer 3, a generator of 4 pulses of variable duty cycle, a generator of 5 pseudo-random pulses, a resistor 6, a switch 7 and a capacitor 8.

Switching filter works as follows.

The signal from the output of the pulse generator 1 repeatedly divides frequency dividers 2, forming a grid of frequencies at their outputs. The signals from the outputs of frequency dividers 2 are fed to the information inputs of multiplexer 3 and, according to the pseudo-random law, in accordance with the state of the generator 5, pseudo-random pulses switch to the input of the driver 4 of the variable duty cycle. The shaper 4 forms from the incoming sequence of bursts of pulses a batch of pulses of the same duty cycle, but of a different frequency, which varies according to

pseudo-random law. Packs of pulses from the codeformer 4 Compiler C, Muzichuk Editor L. Pchelinska Tehred M. Khodanych Proofreader A. Ilyin

Order 2434/54 Edition 901 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

blunt on the controls of the input key 7 and control its operation.

The pulse width of the driver 4 is controlled by the control signal applied to the control input of the driver 4, which allows you to tune the cut-off frequency of the switched filter.

10 F

about rmu l and

the invention

A switching filter comprising a series-connected resistor and switch, the output of which is the output of the switching filter and connected to the first capacitor output, the second output of which is connected to the common bus, and also a switching pulse generator, characterized in that, in order to increase the signal ratio noise at the output of a switched filter, a generator of switching pulses made in the form of series-connected pulse generator and N frequency dividers (where), the outputs of which, with the exception of the last, under are connected to the information inputs of the multiplexer, and the output of the last frequency divider is connected to the clock input of the pseudo-random pulse generator whose outputs are connected to the control inputs of the multiplexer, while the output of the multiplexer is connected to the input of the variable-duty cycle pulse generator, the control input of which is the control signal input and the output is connected to the control key input.

Claims (1)

10 claims A switched filter containing a resistor and a key in series, the output of which is the output of a switched filter and connected to the first output of the capacitor, the second output of which is connected to a common bus, as well as a switching pulse generator, which differs in that, in order to increasing the signal-to-noise ratio at the output of the switched filter, the switching pulse generator is made in the form of series-connected pulse generator 75 and N frequency dividers (where N> 2), the outputs of which, with the exception of the last are connected to the information inputs of the multiplexer, and the output of the last frequency divider is connected to the clock input of the pseudorandom pulse generator, the outputs of which are connected to the control inputs of the multiplexer, while the output of the multiplexer 35 is connected to the input of the pulse shaper of variable duty cycle, the control input of which is the input of the control signal, and the output is connected to the control input of the key.