SU58859A1 - Device for radio telegraphy - Google Patents

Description

The telegraph systems currently used have the following characteristic feature: the duration of the transmitted signals is of the same order with the length of the pauses between them (or negative parcels when operating in both directions), and the ratio between the average duration of the parcels and pauses does not depend on the speed of wiring and equal to approximately one.

This position in wired telegraphy has its own serious reasons, stemming directly from the properties of the wired communication channel.

In radio telegraphy, there is no need to preserve this relationship, since the radio-telegraph channel (we are talking about short-wave communication) allows pulses to pass much shorter than can be used by the fastest telegraph devices. The shortening of the relative length of the signals, in addition to a significant reduction in the energy consumed, may make it possible in some cases to reduce the cost and simplify the design of transmitting devices.

The signal shortening can be carried out by applying an intermediate code change, in which each elementary signal (point) can be transmitted as constant and extremely short along a length, and a complex signal, or several, equally spaced from each other by the same pulses ( a signal equal to, for example, the three points of the dash of the Morse code must be transmitted by three pulses spaced apart from each other for a period of time equal to the duration of the point), or by a single pulse of a correspondingly longer duration.

Shortening signals requires special transitional devices: converting and shortening signals — between transmitting telegraph devices and radio transmitters and restoring their length — between radio receiving devices and receivers and conventional telegraph devices.

The essence of the proposed invention is a wireless telegraph communication device, in which using the simplest means it is possible to use the work by shortened transmissions.

As mentioned, the telegraph signal can be transmitted either by several short messages equally spaced from each other or by one message corresponding to a longer duration.

in the first case, the conversion of signals during transmission and their subsequent restoration at the reception does not cause fundamental difficulties and can be carried out using both electromechanical systems and purely electrical methods. The advantage of this method is the possibility of changing the speed of wiring and the transition to manual work without the necessary re-adjustment of the transitional devices, which must be unregistered to the highest operating speed of this communication channel. As the speed decreases, the number of bursts per signal will only increase.

In the second method, the conversion and restoration of signals is associated with some technical difficulties and leads to complex transition devices. With multi-valued codes, the use of this method is hardly possible.

Therefore, the most appropriate use of transitional devices corresponding to the first method of signal transmission.

The proposed schemes of transitional devices are not complicated and provide reliable conversion of the signal into a series of short pulses, the constancy of their frequency, and the possibility of changing their frequency and duration.

A diagram of the transition device included at the transmitting station is shown in FIG. 1. Here, the resistances and R, the capacitor C and the neon lamp 2 are a pulse generator. The signal from the telegraph unit, which is being driven to points aa, charges capacitor C through kenotron 1 and resistance. When a capacitor is discharged to a neon lamp and resistance / .; lamp 3, acting as the limiter, is locked. Voltage variations on the resistance are used to manipulate the tone generator, which controls the transmitter, or the transmitter itself (the tone generator must be of a higher frequency, at least 3-4 thousand hrs / sec). The purpose of the kenotron 1 and the lamp 4 is to store a certain amount of charge on the capacitor C in the pauses between the signals. This is necessary so that the first half-cycle of oscillations at the beginning of each signal is equal to the next.

The interval between pulses i, equal to the charging time of the capacitor C, is determined by the constant time C / ,, the magnitude of the input signal voltage V and the ignition voltage V, and the extinction of the V-, neon lamp.

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V v

The pulse duration, m, is equal to the burning time of the neon lamp, is determined at /, approximate expression:

, 1p-.

The period of alternation pulses; 7 + t.

The whole system must be adjusted so that the time T is equal to the duration of the elementary signal (point), and t is the set duration of the shortened signal 0.7. 10 sec Some of the frequency instability of the oscillator is of no particular importance, since it operates with small series of oscillations with a duration of several periods. It is necessary that the time T does not exceed the point duration. The extra charge of the capacitor C remaining on it, when T is shorter than a point, is removed by the discharge lamp 4. The process of converting the signals during transmission is shown graphically in FIG. 2

To restore the signal at the reception, transition devices can be used, which have a very short compared to the duration of the received pulses of a constant charge time and an arbitrarily controlled discharge time.

A diagram of such an adapter is shown in FIG. 3. The received impulse charges the capacitor C. The voltage on this capacitor, which is a part of the series-connected battery B, the resistance R and the neon lamp 2, is opposite to the polarity of the battery, as a result of which the neon lamp is charged when the capacitor is charged. goes out. The grid of the lamp 3 is thus at a zero potential.

When a capacitor is discharged by resistance 1 at the moment when the difference between the battery voltage and the voltage across the capacitor reaches the ignition voltage of the neon lamp, the latter flashes; The BOsuHKaiouiee at the same time decreases the resistance voltage to lock the lamp 3.

The constant discharge time of capacitor C is set so that the neon lamp flashes after a period of time somewhat longer than the duration of the point. In this case, a series of pulses corresponding to one signal will control lamp 3 in the same way as one continuous signal.

In order for the moment of ignition of the neon lamp not to depend on the level of the received signals, the latter must be subjected to a preliminary limitation.

The purpose of the kenotron 1 is to open the charge circuit in the pauses between the individual impediments. Its internal resistance must be small enough so that the charge time of capacitor C is much less than the duration of incoming pulses.

Pulses of both direct and alternating current can be supplied to the circuit. In the latter case, a generator of increased sound frequency (not less than 3-4 thousand hours per second), controlled by the receiver limiter, should be used.

The anode current of the lamp 3 is used to actuate writing instruments or receiving relays and to manipulate the acoustic generator of the auditory control.

The signal recovery process is depicted n; 1 in FIG. four.

The subject matter of the invention.

A device for radiotelegraphy, tl and which is used for transmitting signals with the shortest possible pulses on a transmitter, used a transitional device consisting of a pulse generator (one of the capacitors of which is intended to be charged from telegraph signals), which manipulates a tone generator that controls when receiving, a transitional device is applied, the capacitor of which, charged by the received pulses, is connected to the circuit of the battery, the resistance and the neon lamp that goes out when charging zazhigayuscheys capacitor and at its discharge.

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