SU1757093A1 - Frequency selector - Google Patents

Abstract

Summary of the Invention; The selector contains 2 capacitors 1, 2, resistor 3, input bus 4, output bus 5, voltage suppressor 6, 1 element EXCLUSIVE OR 7, common bus 8.2 Il.

Description

Fi & 1

The invention relates to automation and computing and can be used in automatic monitoring and control systems.

A frequency selector is known, comprising a shaper of a rectangular signal, a multivibrator, the output of which is connected to a reacting body, and a node for controlling a multivibrator, a transistor, the base of which through a transformer is connected to the output of a rectangular signal generator

Known frequency selector containing a delay element, a differentiating circuit, the input of which is connected to the output of the delay element, a limiter, the input of which is connected to the output of the differentiating circuit, the element NOT, the input of which is connected to the input of the delay element and the input signal bus, and the element I, the first input which is connected to the output of the limiter, the second input is to the output of the element NOT and the output is to the output bus.

The closest in technical essence to the invention is a frequency selector containing a D-flip-flop, the D-input of which is connected to the input bus and the clock input to the enable signal bus, the first and second elements 2I-NOT, the first input of which is connected to the clock input D-flip-flop, and the second input, respectively, with a direct and inverse output D-flip-flop, the third element 2I-NOT, the output of which is connected to the output bus of the device, a pulse delay unit and a pause delay unit, containing, respectively, the first and second element NOT whose input Connected, respectively, with the output of the first and second elements 2I-NOT, the first and second diodes, the first and second capacitors, the first and second resistors connected in series, respectively, with the first and second capacitors, and the fourth and fifth elements 2I-NOT, the first input of which is connected, respectively, to the output of the first and second elements NOT and the cathode of the first and second diodes, the second input respectively to the anode of the first and second diodes and the first lining of the first and second capacitors, and the output respectively to the first and second at odes third element 2I-NO, and said second electrode of the first and second capacitors is connected to zero C, and the second terminal of the first and second resistors - with a positive power supply bus.

The disadvantage of these devices is the increased complexity, due to the number of elements included in them and the connections between them.

The purpose of the invention is to simplify the selector.

The goal is achieved by the fact that a voltage selector and an exclusive OR element whose output is connected to the output bus, the first input is connected to the frequency selector, which contains the first and second capacitors, the resistor connected in series with the first capacitor, the input and output buses the connection of the resistor and the first capacitor, the second input - with the first output of the voltage limiter, the second output of which is connected to the second output of the resistor and to the common bus, and through the second capacitor - with the input bus and with the second m the output of the first capacitor.

FIG. 1 is a schematic diagram of the proposed selector; in fig. 2 diagrams, which show the work of the selector.

The frequency selector (FIG. 1) contains first 1 and second 2 capacitors, a resistor 3 connected in series with the first capacitor 1, an input 4 and an output 5 bus, a voltage limiter 6 and an EXCLUSIVE OR element 7, the output of which is connected to the output bus 5, the first the input is with the connection point of resistor 3 and the first capacitor 1, the second input is with the first output of voltage limiter 6, the second output of which is connected to the second output of resistor 3 and to the common bus 8, and through the second capacitor the 2nd input bus 4 and c the second output of the first capacitor 1.

The voltage limiter b can be replicated, in particular, on the basis of a zener diode (connected to the power source or without it via a second resistor), the stabilization voltage of which is slightly higher than the minimum level of the logical unit at the input of the EXCLUSIVE OR 7 element.

The selector (figure 1) works as follows.

In the absence of a frequency signal (Fig. 2a), a static zero or a single signal level is detected on the input bus 4 on the second terminals of the first 1 and second 2 capacitors, which does not pass to the inputs of the EXCLUSIVE OR 7 element. At the same time, the first input of the EXCLUSIVE OR 7 element is set a zero signal which is supplied through a resistor 3, and a single signal at the second input, the level of which is determined by the voltage limiter b. To a different input signal level there is a single signal at the output of the EXCLUSIVE element LEE 7 (Figure 2b).

When a frequency signal (Fig. 2a) appears on the input bus 4, the square-wave pulses pass through the first 1 and second 2 capacitors to the inputs of the EXCLUSIVE OR 7 element, causing common mode changes in the signal levels. As a result, a zero signal is set at the output of the EXCLUSIVE OR 7 element (FIG. 26).

Those. when a device imparts rectangular pulses with a frequency not lower than the specified one, a zero signal level is established at the device output, and, on the contrary, the disappearance of the frequency signal leads to the appearance of a single signal level on the output bus 5 of the device.

Thus, the selector provides for the selection of rectangular signals in frequency according to the frequency relay principle.

The known devices that perform a similar function have a more complex circuit design, which causes increased costs for their implementation and reduced reliability of their work.

The proposed selector is simpler known, with the result that it is cheaper to manufacture and more reliable in operation. The specified quality determines the technical and economic advantage of the device.

It is advisable to use the selector to control the frequency circuits of the clock devices.

Claims (1)

The invention includes a frequency selector containing the first and second capacitors, a resistor connected in series with the first capacitor, an input and output bus, characterized in that, for the sake of simplicity, a voltage suppressor and an element EXCLUSIVE OR, whose output is connected to the output bus, the first input is with the connection point of the resistor and the first capacitor, the second input is with the first output of the voltage limiter, the second output of which is connected to the second output of the resistor both to the common bus and through the second condensation Or - to the input bus and to the second terminal of the first capacitor. Ft.2