RU2259637C2 - Method for sound broadcast signal transmission over duplex digital communication channel - Google Patents

Abstract

FIELD: communications; digital sound broadcast signal transmission systems.

SUBSTANCE: proposed method for transmitting sound broadcast signals over duplex digital communication channel includes following operations: on sending end N analog sound broadcast signals are converted into digital signals which are compressed by way of coding in frequency band and conveyed at speed of V kbit/s to receiving end whereon they are converted into analog sound broadcast signals; M reverse-direction analog sound broadcast signals are converted into digital signals which are shaped by means of instant or almost instant companding, or differential pulse-code modulation (DPCM), or delta modulation (DM) and transmitted at same speed of V kbit/s.

EFFECT: enhanced quality of sound broadcast signal, reduced cost of equipment and delay time when coding this signal in frequency band.

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Description

The invention relates to the field of communication, mainly to sound broadcasting, and can be used in digital systems for transmitting sound broadcasting signals (SV).

A known method of transmitting sound broadcasting signals on urban radio networks [V.A. Leonov, O.O. Kumushev Organization of digital channels in urban networks of wire broadcasting. Technology and communications, No. 5, 2000, OOO ″ Grotek ″], which consists in the fact that the analog audio broadcast signal is converted into a digital signal, which is compressed using coding in the frequency domain and transmitted over a duplex digital communication channel in the ″ point-to-point mode point".

The transmission method closest in technical essence is the method of transmitting audio signals, namely, that the digital audio signal is encoded in the frequency domain on the transmitting side and transmitted to the receiving side at a constant speed, where the signal is decoded and converted into a digital audio signal (a.s USSR No. 1821927, MKI, H 04 J 13/00, B.I. No. 22, 1993).

However, the known methods have the following disadvantages: for the formation of a duplex SV channel, it is necessary to install one SV codec at both ends of the channel, each of which contains a complex and expensive SV encoder and decoder, the conversion process takes a long time up to several hundred milliseconds, and in addition, Such a conversion makes it practically impossible to organize retrieval at a low frequency (LF), and this phenomenon is associated with the process of compression of the pollutant signal, which leads to signal distortion upon repeated compression uu signal SG already been subjected to compression.

The aim of the invention is to improve the quality of the pollutant signal, reducing the cost of channel-forming equipment and reducing the delay time associated with the encoding of the pollutant signal in the frequency domain.

This goal is achieved by the fact that in the method of transmitting SV signals over a duplex digital communication channel, which consists in the fact that on the transmitting side N analog audio signals are converted into digital signals, which are compressed using encoding methods in the frequency domain, and with a speed of V kbit / c are transmitted to the receiving side, where they are converted into analogue signals by pollutants, according to the invention, M analog signals of sound broadcasting of the opposite direction are converted into digital signals, which are formed using the method s instantaneous or almost instantaneous companion, differential PCM (DPCM) or delta modulation (DM), and transmit with the same V kbit / s speed.

The method is carried out by introducing the following operations: M analog audio signals of reverse broadcasting are converted into digital signals, which are formed using the methods of instant or almost instant compand, DPCM or DM, and transmit with the same V kbit / s speed. As a result, the delay of the SV signal decreases by a factor of ten, for example, at a sampling frequency of 48 kHz it is only 24 microseconds, there is no signal distortion associated with the conversion in the frequency domain, and the cost of the encoder and decoder in the return channel is reduced.

A method of transmitting SV signals over a duplex digital communication channel, namely, that on the transmitting side N analog audio signals are converted into digital signals, which are compressed using encoding methods in the frequency domain, and are transmitted to the receiving side with a speed of V kbit / s, where they are converted into analogue signals by airborne pollutants, and then L from N analog signals of direct airborne pollutants obtained after the inverse conversion of digital signals of airborne signals compressed in the frequency domain formed using the methods of instant or almost instant companding, DPCM or DM, and transmit with a speed of V1 kbit / s in the same direction as N signals of pollutants. As a result, the delay of the pollutant signal decreases, and there is no distortion of the signal associated with yet another conversion in the frequency domain.

A method of transmitting SV signals over a duplex digital communication channel, namely, that on the transmitting side N analog audio signals are converted into digital signals, which are compressed using encoding methods in the frequency domain, and are transmitted to the receiving side with a speed of V kbit / s, where they are converted into analogue signals by airborne pollutants, and then L from N analog signals of direct airborne pollutants obtained after the inverse conversion of digital signals of airborne signals compressed in the frequency domain formed using the methods of instant or almost instant companding, DPCM or DM, and alternately transmit with a speed of V2 kbit / s in the opposite or the same direction as N signals of pollutants. As a result, the delay of the pollutant signal decreases, there is no distortion of the signal associated with yet another conversion in the frequency domain, the transmission speed increases, and the quality of the pollutant signal increases.

The method is as follows. At the input of the Descartes codec [1] codec, an analogue signal is applied, which is converted into a digital signal and encoded in the frequency domain. A digital signal from the output of the ST codec is fed to the input of a digital communication channel. On the receiving side, a digital signal from the output of the communication channel is fed to the input of the ST codec, where the inverse transform is performed and an analogue ST signal is obtained. Similar operations are performed in the reverse prototype channel. In the proposed method, a signal is fed back into the digital communication channel, which is generated using the methods of instantaneous or almost instantaneous companding, DPCM or DM, which are implemented in the CO codec. Likewise formed by the SV codec L from N digital SV signals are transmitted through a digital communication channel in the same direction as N SV signals. Likewise, the L L codec generated by the codec from N digital signals is alternately transmitted in a forward or reverse direction over a digital communication channel.

Claims (3)

1. The method of transmitting audio signals through a duplex digital communication channel, which consists in the fact that on the transmitting side N analog audio signals (ST) are converted into digital signals, which are compressed using encoding methods in the frequency domain, and at a speed of V kbit / s transmit to the receiving side, where they are converted into analogue signals by pollutants, characterized in that M of the analog signals of sound broadcasting of the opposite direction are converted into digital signals, which are formed using instant or almost m instantaneous companding, or differential PCM (DPCM), or delta modulation (DM) and transmit at the same V kbit / s speed. 2. The method according to claim 1, characterized in that L of N direct forward analogue analog signals obtained after reverse conversion of digital optical signals compressed in the frequency domain are converted into digital signals, which are generated using instant or almost instant compression methods, or DPCM, or DM, and transmit at a speed of V1 kbit / s in the same direction as the N signals of the pollutant. 3. The method according to claim 1, characterized in that L of N direct forward analog analog signals obtained after reverse conversion of digital optical signals compressed in the frequency domain are converted into digital signals, which are generated using instant or almost instant compression methods, or DPCM, or DM, and alternately transmit at a speed of V2 kbit / s in the reverse or the same direction as the N signals of the pollutant.