SU420132A1 - METHOD OF DUAL TELEPHONE - Google Patents

Description

one

The invention relates to the field of multi-channel communication technology and can be used in the equipment of divided channels.

A well-known method of double telephony, consisting in dividing the spectrum of the transmitted signal into two parts, creating free gaps in one of the parts and filling in the free gaps of speech information.

The disadvantage of this method is the low quality of the received signal.

In order to improve the quality of the received signal according to the proposed method, free gaps are created in the first part of the spectrum through filters, and samples are made in the second part of the spectrum, which are modulated into the said free gaps.

On fng. 1 is a diagram illustrating the proposed method; in fig. 2 - the same, more simple option.

From the range of conversational current entering the input, bandpass filters 1, 2 and 3 select frequency bands of 3000-610, 920-1230 and 1540-1700 Hz, which then pass the subchannel directly. Band-pass filters 4 and 5 V 3bet, from the same spectrum, frequency bands 2160-2470 l 2780-3090 Hz, which are then fed to modulator 6 with a carrier frequency of 3700 Hz and converted into frequency

bands 1230-1540 and 610-920 Hz. allocated by the filter. 7 and S.

As a result, a compact frequency spectrum of 300–1700 Hz goes to the subchannel, and the frequencies from the upper half of the telephone spectrum are also represented in a transformed form (an analogous device is applied to the receiving part as well — the receiving direction in Fig. 1 is shown in dotted lines).

The lower band of the telephone spectrum (Fig. 2) is divided into the most numerous number of bands than in the present case (three instead of five), we will also accept only one frequency band 2368--2885 rti in the upper half of the spectrum. This scheme requires fewer filters than the previous one (four instead of seven).

The essence of the proposed way of the south za.pochatsya in with; 1 and 1 ..

The frequency band of 300-1700 Hz of each of the channels, of the lelein channel, is divided, in turn, with band-pass filters into several linc TOTiibix bands. Odd bands, for example, a third, etc., are transmitted to the sub-peppellst subcannel. and even bands, second, fourth, etc., are replaced with modulus by frequency bands of the same width, respectively released from different parts of the frequency range.

located between the frequencies of 2000 and 3400 Hz. The frequency bands resulting from this modulation are then transmitted over the subchannel.

At the receiving end, the frequency bands, first, third, etc., are received directly, and the bands located along them are converted by modulation in such a way that they occupy their previous position in the range of 2000-3400 Hz.

As a result, the received speech speech lect. Contains not only frequencies from the lower half of the telephone spectrum, but also frequencies from the upper half of the spectrum, which increases the intelligibility and naturalness of the received speech.

To simplify the hardware, the frequency bands are chosen in such a way that non-biasing is performed using a carrier frequency of 370 Hz, which already exists in the hardware of the divided channel.

Subject invention

The dual telephoning method, which consists in dividing the spectrum of the transmitted signal into two parts, creating free gaps (In one of the parts and filling the free gaps with voice information, characterized in that, in order to improve the quality of the received signal, free gaps are created in the first part of the spectrum by filters , in the second part of the spectrum, samples are made that are modulated into free spaces.

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