SU783989A2 - Frequency range change-over switch - Google Patents

Description

The invention relates to computing and measuring technology. Known switch frequency bands on the main author. St. W37689 containing limiter, valves, standby multivibrator and output three heras. . The disadvantages of this device are low noise immunity and low reliability due to the fact that in case of equality of the frequency of the input signal with the switching frequency, there is an ambiguity of the switchable range, since in this case, the operation of the triggers is not defined. In addition, systems always have interference and frequency fluctuations at the device input, which leads to random range switching, and this will be a source of interference for devices that use a frequency range switch. In order to increase noise immunity and reliability, a key switch containing a limiter, valves, riggers and a standby multivibrator connected through a limiter to the input of the switch and via valves to the trigger inputs, the output of one of which is connected to the output bus of the device, has been entered, in order to increase noise immunity and its input is connected to the output bus of the device, and the output is connected to another input of the multivibrator. The drawing shows the functional diagram of the crossbar. The switch contains a limiter 1 connected to the input of the valve 2 and through a standby multivibrator 3 with controlled pulse duration to the input of the valve 4, the trigger 5, 6 and the key 7. The output of the trigger 5 is connected to the output bus of the device. The frequency band switch works in the following way. The variable frequency input signal is supplied to limiter 1. From its output, square-wave pulses, the duration of which is equal to half a period, are sent to valve 2 and to the waiting multivibrator 3 with controlled pulse width, which is triggered on the leading edge and produces square-wave pulses , 2i; „er.

de Sper. the switching frequency of the tap can take two values

Munep. and uunfep OLJp.ep.- bV «Jnep. (tw lane,

the value of the hysteresis zone of the switching frequency).

With the help of valves 2 and 4, the durations of the rectangular pulses of the multivibrator 3 and the limiter are analyzed; 1, moreover, if the duration of the pulses of the multivibrator 3 is longer than the duration of the pulses of the limiter 1, there is a signal at the valve 4 output, otherwise, the signal is at the output of the valve 2. Signals from the valve 2 trigger a trigger 5, the signals from whose output reset the trigger 6. So Thus, at the output of the device there is a signal if trigger 5 is running. This means that the frequency of the input signal is less than the switching frequency.

If there is a signal on the output bus of the device, the key 7 is triggered, 1 in which the duration of the pulses of the waiting multivibrator 3 decreases, and the switching frequency is increased by the value of A. That ensures a reliable preservation of the output signal in the case when the frequency of the input signal is equal to the switching frequency of Shper, and the presence of interference and fluctuations in the frequency of the input signal. Value / iiOLinep. determined by the required

and switching hysteresis depending on the magnitude of the noise and fluctuation of the frequency of the input signal.

If the frequency of the input signal rises and becomes greater than UuneprtJWnep

 & Shper | Trigger 6 is triggered, resetting Trigger 5, and there is no signal at the output of the device, which will turn off switch 7, as a result of which the duration of the pulses of the waiting multivibrator 3 increases. The switching frequency at this takes its value.

Claims (1)

Invention Formula 0 The switch frequency bands for auth. St. 376893, from the fact that, in order to increase noise immunity and reliability, a key was inserted into it, with its input connected to the output bus of the device, and the output to another input of the waiting multivibrator. 0