RU2490727C2 - Method of transmitting speech signals (versions) - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method of transmitting speech signals includes breaking down the speech signal into equal fragments, encoding said fragments, sending to a communication channel, decoding and constructing the speech signal from the fragments, the method being characterised by that at the transmitting side, two speech signals are selected instead of one speech signal; each is broken down into equal fragments; all even fragments are deleted from the first speech signal and all odd fragments are deleted from the second speech signal; the remaining fragments are encoded and sent to a communication channel; at the receiving side, for the first speech signal, even fragments deleted at the transmitting side are replaced with previously obtained odd fragments from the first speech signal, and for the second speech signal, odd fragments deleted at the transmitting side are replaced with previously obtained even fragments from the second speech signal.

EFFECT: transmitting speech signals in a narrowband channel, transmitting two speech signals with acceptable quality over one available channel.

2 cl, 10 dwg

Description

The invention relates to multi-channel communication systems, and in particular to systems in which the narrowing of the frequency spectrum of individual signals and the subsequent expansion of this spectrum are applied.

A known method of transmitting speech signals (Igor Ivantsov, Protocol stacks. Transmission quality in VoIP networks. LAN network solutions log. - 2007, N 5. - P.34-35), in which the speech signal on the transmitting side is split into equal fragments, encoded , and on the receiving side it is decoded, while the missing fragments of the speech signal are replaced by the last received fragments.

The disadvantage of this method is the inability to transmit a signal in a narrowband channel, as well as the inability to simultaneously transmit two speech signals.

The aim of the invention is the transmission of speech signals in a narrowband channel, as well as the transmission of two speech signals with acceptable quality on one available channel.

This goal is achieved by the fact that even or odd fragments are removed from the sequence of speech fragments.

The essence of the invention according to claim 1 is that on the transmitting side, each even fragment of the speech signal is deleted, and the odd fragments are stretched by the size of the deleted even fragment, on the receiving side, the obtained stretched fragments are compressed twice, and the previous received fragment is put in place of the missing even fragments a compressed fragment, and the essence of the invention according to claim 2 is that instead of one speech signal, two speech signals are taken on the transmitting side, each divided into equal fragments, from the first speech system all odd fragments are deleted, and all the odd fragments from the second speech signal, encode the remaining fragments, sent to the communication channel, on the receiving side for the first speech signal, the even fragments deleted on the transmitting side are replaced by the previous received odd fragments from the first speech signal, and for the second speech signal, the odd fragments removed on the transmitting side are replaced by the previous received even fragments from the second speech signal.

The coding of fragments of a speech signal on the transmitting side can be performed in any known manner, it is also possible to transmit fragments of a speech signal in analog form, that is, without using coding.

Figure 1 shows the speech signal, divided into fragments: 1, 3, 5 odd fragments, 2, 4 even fragments. Figure 2 presents the speech signal from which even fragments are removed. Figure 3 presents the speech signal in which the odd fragments are stretched in time twice. Figure 4 presents the received speech signal, in which fragments are compressed twice. Figure 5 presents a speech signal in which even fragments are replaced by the last received odd fragments. Figure 6 presents the second speech signal. 7 shows a second speech signal from which the odd fragments are removed. On Fig presents the sum of the first and second speech signal. Figure 9 presents the first speech signal after replacing the missing fragments with the last received. Figure 10 presents the second speech signal after replacing the skipped fragments with the last received.

The proposed method is as follows.

The speech signal is divided into a sequence of equal fragments (figure 1). It is empirically established that the duration of the fragment lies in the range from 5 ms to 100 ms, the optimal duration is 20 ms. Even fragments are removed from the sequence (Fig. 2), odd fragments are stretched twice (Fig. 3), the resulting sequence is encoded and transmitted to the communication channel, and on the receiving side, the fragments obtained are compressed twice (Fig. 4), the missing even the fragments are replaced by the previous odd fragments obtained (FIG. 5). As a result, a channel with a smaller spectrum is needed for transmission. For option 2, on the transmitting side, even fragments are removed from fragments of the first speech signal of the same duration (Fig. 2), odd fragments are removed from fragments of the second speech signal (Fig. 7), the fragments remaining from both speech signals are added (Fig. 8) and transmitted to the communication channel. On the receiving side, these fragments are separated, while for the first speech signal the missing even fragments are replaced by the previous received odd fragments (Fig. 9), and for the second speech signal the missing odd fragments are replaced by the previous received odd fragments (Fig. 10). Thus, two speech signals are transmitted simultaneously on one channel.

Since the fragments of the speech signal are small, the removal of some of them (even or odd) does not distort the transmitted speech signals until they are illegible, and at the output of the receiving side for both considered options we obtain speech signals of acceptable quality due to the smallness of the fragment, and also because of inertness human ear.

Thus, the proposed method for transmitting speech signals allows you to transmit a speech signal over a narrow-band channel, as well as transmit two speech signals simultaneously on one channel.

Claims (2)

1. A method of transmitting speech signals, including splitting the speech signal into equal fragments, encoding them, sending them to the communication channel, decoding, composing a speech signal from fragments, characterized in that on the transmitting side each even fragment of the speech signal is deleted, and the odd fragments are stretched to the size of the deleted even fragment, on the receiving side, the obtained stretched fragments are compressed twice, and the previous received compressed fragment is put in place of the missing even fragments. 2. A method of transmitting speech signals, including splitting the speech signal into equal fragments, encoding them, sending them to the communication channel, decoding, composing a speech signal from fragments, characterized in that on the transmitting side, instead of one speech signal, two speech signals are taken, each divided into equal fragments, all even fragments are removed from the first speech signal, and all odd fragments from the second speech signal, encode the remaining fragments, sent to the communication channel on the receiving side for the first speech Of the signal, the even fragments deleted on the transmitting side are replaced by the previous received odd fragments from the first speech signal, and for the second speech signal, the odd fragments deleted on the transmitting side are replaced by the previous received even fragments from the second speech signal.

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