SU471674A1 - Telegraph type transmission method - Google Patents

Description

one

The invention relates to methods for transmitting signals, in particular to methods for transmitting signals of a telegraph type.

The known method of transmitting telegraph-type signals over physical circuits and high-frequency channels with a carrier frequency does not provide an increase in protection against reception interference.

The purpose of the invention is to increase protection against interference with reception.

This is achieved by converting the pause waveforms from cosine to square, and the sending signals are filled with high frequency vibrations.

FIG. 1 shows a block diagram of a receiving device that implements the proposed method; in fig. 2-time digram, which reads receiver operation.

Irin you have the following designations: input voltage amplifier I; two-sided limiter 2 and voltage waveform converter; differentiating circuit 3; the second amplifier 4; differentiating circuit 5; limiter 6 amplitudes of the total voltage of the signal; local oscillator 7 frequency / g / selector 8 high harmonic frequency / n / g heterodyne; amplitude detector 9.

FIG. 2, a shows a manipulated signal voltage in which the parcel corresponds to the function ± 1, and the pauses between the parcels are the cosine frequency sections of the fcIn limiter 2 simultaneously with the deep voltage suppressor, the cosine half wave of the square wave converts into a quadratic (almost square) curve while preserving the sections of the zfcl function (Fig. 2.6).

The result of voltage differentiation (Fig. 26) in differentiating circuit 3 is shown in Fig. 2, c. Here, the areas of the quadratic curve correspond to the linearly varying voltage, and the parts of the function ± 1 correspond to the bullet voltage; after differentiating a given voltage differentiating

circuit 5 creates the voltage shown in fig. 2 g. In this voltage, the intervals of the bullet voltage are stored, and the gaps between them are filled with alternating rectangular voltage.

The time constants of both differentiation chains are the same. To meet the requirements of inertia-free and high noise immunity, they must be several times less than the half-time duration

-: -., (4-6 times).

Next, the voltage (Fig. 2g is added to the voltage of the local oscillator 7, the resulting voltage is limited in amplitude, and using the selector 8, the tuned frequency is formed, the high frequency packages are almost equal in length to the signal messages (Fig. 2b). The output of the amplitude detector 9 is unipolar parcels (Fig. 2e). The selection path must be inertia-free relative to the duration of the elementary interval to, i.e. the time for establishing oscillations in the selection path must be e. This is ensured if the bandwidth of the 2Af selection path is significant for the FC signal, but the condition 2Af ":; 20Fc is completely met the condition of the invention. The method of transmitting telegraph type signals over physical circuits and its frequency is different. , and so that, in order to increase the gain from receiving interference, the waveforms of the cosine wave are converted into rectangular signals, and the send signals are filled with high-frequency vibrations.

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