SU450378A1 - Optoelectronic key - Google Patents

Description

one

The invention relates to telegraph receivers (electronic switches, relays) used in communication engineering, in particular, for interfacing radio devices with telegraph communication channels and telegraph devices.

Known electronic telegraph keys containing converters, inverter and trigger. In these keys for galvanic uncoupling of the telegraph channel with a radio engineering device, telegraph parcels coming from the communication channel are transformed with one or two blocking generators into high-frequency pulses, which are then transformed, rectified and fed to the input of the radio engineering device.

However, the well-known keys provide interface with telegraph channels only during single-pole operation. The maximum speed of their work does not exceed 1200 baud. The power supply to the inverter and the converters should be from an additional power source not galvanically connected to the radio. In addition, these keys are relatively complex due to the use in them of galvanic isolation of a radio engineering device with a communication channel of blocking generators, transitional transformers and two power sources, and create significant interference with radio reception

due to the electromagnetic radiation produced by the converters, especially when changing the sign of the telegraph parcels. The trigger operation in them depends on the nature of the load (capacitive, inductive), since it is electrically connected to the charge-discharge circuit of the switching capacitor. The transducers add additional distortion to telegraphic parcels.

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The purpose of the invention is to simplify the key scheme, increase its reliability in operation, eliminate electromagnetic radiation, ensure operation at high wiring speeds and eliminate dependence of the trigger operation on the nature of the load. This is achieved by the fact that the static trigger is made on series-connected photo thyristors and resistors, the junction points of which are connected to

the photothyristors are interconnected through a switching capacitor. In this case, one of the power supply wires is connected to a static trigger via a resistor, in parallel with which the input of the additionally introduced threshold device is connected. The latter is performed on a transistor connected in a circuit with a common emitter, to the base of which a zener diode is connected. The drawing shows the proposed scheme

key.

Trigger 1 key is built on thyristor ontrons 2, 3, resistors 4, 5 and switching capacitor 6. Threshold device 7 consists of transistor 8, resistor 9 and zener diode 10. Radio device 11 is connected to collector of transistor 8. Light diodes 12 and 13 optocouplers are turned on anti-parallel and through a resistor 14 are connected to the input 15 of the key, to which the telegraph channel is connected. The key is powered from the voltage source 16.

The resistance of the resistor 5 is chosen such that when the optocoupler 3 is turned on, the current flowing through the resistor 9 creates a voltage on it that is much less than the stabilization voltage of the Zener diode 10.

The resistance of the resistor 4 is chosen such that when the optocoupler 2 is turned on, the voltage drop across the resistor 9 is several times greater than the stabilization voltage of the zener diode 10 and the transistor 8 is completely saturated with the current of the zener diode.

The ratio between the capacitor capacitance and the resistors 4, 5 must be such that at the maximum wiring speed the capacitor has time to fully charge and discharge.

Parallel to the input 15, two oppositely connected Zener diodes 17 and 18 are connected, which together with the resistor 14 provide protection of the LEDs against possible overvoltages.

In the initial state, when there is no voltage at the key input, the optocouplers 2 and 3 are closed, the current in the base circuit of transistor 8 is absent, and the radio device is de-energized.

When a positive polarity arrives at the input 15 of the telegraph parcel, the LED 12 is energized and the photo thyristor of the optocoupler 2 is switched on via a circuit: plus a power source 16 (+), resistors 9 and 4, a photo thyristor optron 2, minus the power source 16. it is enough to turn on Zener diode 10 and current flows through the base circuit of transistor 8. The transistor opens and a plus power supply 16 is connected to the input of the radio device.

The switching capacitor 6 is charged along the circuit:, base-emitter junction of transistor 8, zener diode 10, resistor 5, photo-thyristor of optocoupler 2, -E. The bottom plate of the capacitor is charged positively relative to the top plate.

When a negative polarity signal arrives at the input 15, the LED 12 is de-energized and the LED 13 is energized. This turns on the photo thyristor of the optocoupler 3 along the circuit: - {- E, resistor 9, resistor 5, phototiristor of the optocoupler 3, -E.

When the photo thyristor of the optocoupler 3 is turned on, the voltage of the capacitor 6 is applied to the anode of the photo thyristor of the optocoupler 2 and locks it. The current flowing through the optocoupler 3 creates a voltage across the resistor 9 that is insufficient for

turning on the Zener diode 10; the current in the base circuit of the transistor 8 stops and the load is de-energized. The charge and discharge of the switching capacitor occurs through resistors 4, 5 and does not depend on the nature of the load.

When the optocoupler 3 is switched on, the top plate of the capacitor 6 is positively charged, therefore upon subsequent receipt of the positive polarity from the communication channel, the optocoupler 2 is turned on and the ontiron 3 photo thyristor is closed by the voltage of the capacitor.

Thus, depending on the polarity of the telegraph parcels coming from the communication channel, the power source is connected

to the input of the radio device or disconnected from it.

Subject invention

Claims (2)

1. Optoelectronic key for mating radio telegraph communication devices, containing a static trigger, whose input is connected to a communication channel, characterized in that, in order to increase speed and exclude electromagnetic radiation, a static trigger is made on series-connected photo thyristors and resistors, whose connections to photo thyristors are interconnected via a switching capacitor, while one of the power rails is connected to a static trigger through a resistor, in parallel with which an input of an additionally introduced threshold device is connected. 2. An optoelectronic switch according to claim 1, characterized in that the threshold device is made on a transistor connected in a circuit with a common emitter, to the base of which a zener diode is connected. ; j IS