JP2684125B2 - Audio processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station-side voice processing apparatus used in the digital mobile communication field.

[0002]

2. Description of the Related Art In recent years, voice processing apparatuses have been developed to be incorporated in base stations or exchanges of digital automobile telephone systems in various countries. The positioning of such a voice processing device in the system will be described below.

FIG. 2 shows a schematic configuration of a digital mobile communication system. In FIG. 2, 11 is a mobile device,
Reference numeral 12 is a base station, and 13 is a mobile communication exchange. Reference numeral 14 denotes a receiver of the mobile device 11, which converts voice into an electric signal and transmits it from the transmission / reception device 15 through the mobile device antenna 16. Reference numeral 17 denotes a base station antenna, which demodulates the received voice signal by a modulator / demodulator 18 of the base station 12 and decodes an upstream high efficiency coded voice signal 19 by a voice processor 20. 21
Is the decoded upstream PCM data, which is input to the mobile telecommunication exchange 13 and input to another mobile telecommunication exchange 13 through the 4-wire transmission path 22.

Reference numeral 23 is downlink PCM data, and the base station 1
2 is input to the voice processing device 20. Reference numeral 24 denotes a downlink high-efficiency coded voice signal, which is used by the modulator / demodulator 18 of the base station 12.
Is being entered. The voice signal modulated by the modulator / demodulator 18 is transmitted from the base station antenna 17 and received by the mobile station antenna 16, demodulated and decoded by the transceiver 15 of the mobile station 11, and output from the speaker 25.

A subscriber line switch 26 is connected to a fixed telephone 27 via a two-line transmission line 28 and is connected to a fixed line 27.
It is connected to the mobile communication exchange 13 via the line transmission line 29. 30 is a PCM codec, 31 is an audio signal output, 32 is an audio signal input, and the hybrid circuit 3
Input and output to 3.

Next, the operation of this digital mobile communication system will be described. The mobile phone 1 is used as a call form.
Two modes can be considered: one-to-one fixed telephone 27 call and mobile station 11-to-mobile station 11 call. Mobile phone 11-to-fixed telephone 27 call in voice mode, mobile phone 11-to-mobile phone 11
Call will be called 1-link mode.

In the voice mode, first, in the mobile unit 11, voice is converted into an electric signal by the receiver 14, is subjected to voice coding processing by the transmission / reception unit 15 into a high efficiency coded voice signal, and is then modulated, and is then transmitted to the mobile unit antenna. 16 is sent. The voice signal received by the base station antenna 17 is demodulated by the modulator / demodulator 18 of the base station 12 and output as an upstream high efficiency coded voice signal 19. The upstream high-efficiency coded audio signal 19 is decoded by the audio processing device 20, and 8-bit PCM is output as the upstream PCM data 21.
The upstream PCM data 21 enters the other mobile telecommunication switch 13 from the mobile telecommunication switch 13 through the four-line transmission line 22, then enters the subscriber line switch 26 via another four-line transmission line 29, and enters the PCM codec 30. Reach PCM codec 3
The PCM data input to 0 is converted into an audio output signal 31 and further subjected to 2-wire conversion by the hybrid circuit 33,
The fixed telephone 27 is reached via the two-wire transmission line 28.

On the contrary, the voice signal input from the fixed telephone 27 is separated by the hybrid circuit 33 via the two-wire transmission line 28, and the PCM codec 30 is used as the voice input signal 32.
And becomes PCM data of 8-bit PCM. This PCM data is input to the voice processing device 20 of the base station 12 as the downlink PCM data 23 via one or more mobile communication exchanges 13 to first remove the echo canceller generated in the hybrid circuit of the fixed line network, and then A voice coding process is performed and a downlink high efficiency coded voice signal 24 is output. The downlink high-efficiency coded voice signal 24 is modulated by the modulation / demodulation device 18 of the base station 12 and transmitted from the base station antenna 17. The voice signal received by the mobile station antenna 16 is
The transmitter / receiver 15 of the mobile device 11 demodulates and decodes the voice, and the speaker 25 outputs the voice.

In the 1-link mode, on the other hand, in the mobile unit 11, the voice is converted into an electric signal by the receiver 14, the voice coding processing is carried out by the transmitting / receiving unit 15 into a high-efficiency coded voice signal, which is then modulated. It is transmitted from the antenna 16. The voice signal received by the base station antenna 17 is demodulated by the modulator / demodulator 18 of the base station 12 and output as an upstream high efficiency coded voice signal 19. The upstream high-efficiency coded speech signal 19 is decoded by the speech processing device 20 and converted into 8-bit PCM, and a signal obtained by adding a synchronization pattern to the upstream high-efficiency coded speech signal 19 is converted into an 8-bit PC.
It is embedded in the lower 2 bits of M and is output as the upstream PCM data 21.

FIG. 3 shows an example of a data bus format between the exchange and the voice processing device. In the voice mode, 8 bits are PCM data, in the 1-link mode, upper 6 bits are PCM data and lower 2 bits are a synchronization pattern and a high-efficiency coded voice signal.

Returning to FIG. 2, the upstream PCM data 21 is
The downlink PCM data 2 is transmitted as PCM data through the mobile telecommunication exchange 13 and at least one other telecommunication switch 13.
As 3 the voice processing device 20 of the base station 12 on the other side is reached. In the voice processing device 20, first, the echo canceller is turned off, the synchronization pattern of the lower 2 bits of the downlink PCM data 23 is monitored, and when synchronization is established, the high-efficiency coded voice signal included in the lower 2 bits. Is output as it is, and the high efficiency downlink encoded audio signal 24 is output. If the synchronization cannot be established, it is determined that the call is with the fixed telephone 27, the downlink PCM data 23 is encoded, and the high-efficiency encoded voice signal 24 is output.

The downlink high-efficiency coded voice signal 24 is modulated by the modulator / demodulator 18 of the base station 12 and transmitted from the base station antenna 17. The voice signal received by the mobile station antenna 16 is demodulated and voice-decoded by the transmission / reception device 15 of the mobile station 11, and a voice is output from the speaker 25. The reverse route has exactly the same operation.

With the above operation, in the 1-link mode, the voice quality is not deteriorated by performing the voice code decoding process twice by passing through the voice processing device 20 twice. Further, PCM is inserted in the upper 6 bits so as to handle the case where the called mobile unit 11 transfers the call to the fixed telephone 27 by transferring the incoming call or the like.

Next, details of the conventional voice processing apparatus 20 will be described with reference to FIG. In FIG. 4, reference numeral 34 is a decoder, which receives the upstream high-efficiency coded audio signal 19 and outputs the upstream PCM data 21. 35 is an echo canceller, which is an upstream PCM
The data 21 and the downlink PCM data 22 are input.
The downlink PCM data 23 is also input to the selection switch 36. Reference numeral 37 is an echo canceller output. Reference numeral 38 is an encoder, and a down switch PCM is provided via the selection switch 36
The data 23 or the echo canceller output 37 is selectively input, and the downlink high efficiency coded voice signal 24 is output. 3
Reference numeral 9 is a control signal interface with the exchange, and a control signal 40 from the converter is input / output. Reference numeral 41 is a mode setting signal, and 42 is an echo canceller on / off switching signal.

The voice processing device 20 configured as described above.
The operation will be described below. First, when the exchange confirms the call origination, a signal in which the mode setting signal 41 is added to the control signal 40 is sent to the control signal interface 39 of the voice processing device 20. The control signal interface 39 informs the encoder 38 and the decoder 34 of the operation mode through the mode setting signal 41.

The decoder 34 decodes the upstream high-efficiency coded audio signal 19 in the audio mode and outputs 8-bit PCM as the upstream PCM data 21. The upstream PCM data 21 is also input to the echo canceller 35 as a reference value. In the 1-link mode, the upstream high-efficiency coded audio signal 19 is decoded to obtain an 8-bit PCM, and then the synchronization pattern and the upstream high-efficiency coded audio signal 1 are assigned to the lower 2 bits.
9 is mapped and output.

In the voice mode, the encoder 38 turns on the echo canceller 35 by the echo canceller on / off switching signal 42, sets the selection switch 36 to select the echo canceller output 37, and encodes the echo canceller output 37. And outputs the downlink high-efficiency coded audio signal 24. At this time, the echo canceller 35
Uses the upstream PCM data 21 as a reference value to remove the echo generated in the hybrid circuit of the downstream PCM data 23 coming from the fixed line network. Further, in the 1-link mode, the echo canceller 35 is turned off by the echo canceller on / off switching signal 42, and the selection switch 3
6 sets the downlink PCM data 23 to be selected, and the downlink P
When the synchronization pattern of the lower 2 bits of the CM data 23 is monitored and the synchronization is established, the high-efficiency coded audio signal contained in the lower 2 bits is replaced as it is, and the downlink high-efficiency coded audio signal 24 is converted. Output. If the synchronization cannot be established, it is determined that the call is with the fixed telephone 27, the downlink PCM data 23 is encoded, and the high-efficiency encoded voice signal 24 is output.

As described above, even the above-described conventional voice processing device can process the voice signal corresponding to the voice mode and the 1-link mode.

[0019]

However, in the above-described conventional voice processing apparatus, the echo canceller is always turned off in the 1-link mode. Therefore, in communication between mobile units, the mobile unit on the called side transfers the incoming call. When switching to the fixed telephone side due to this, there is a problem that the echo generated in the hybrid circuit cannot be removed, which causes deterioration of voice quality.

If synchronization cannot be established, it is judged that the communication is with a fixed telephone and the echo canceller is turned on. Even if 8-bit data including the synchronization pattern comes thereafter, the synchronization pattern is destroyed by the echo canceller. Therefore, there is also a problem that synchronization cannot be established.

The present invention solves such a conventional problem. Even in the 1-link mode, the echo generated in the hybrid circuit can be removed when the call is transferred to the fixed telephone by the call transfer. It is an object of the present invention to provide an excellent audio processing device that can perform synchronization immediately even if 8-bit data including a synchronization pattern comes after synchronization is not established.

[0022]

In order to achieve the above object, the present invention provides a control interface for receiving a control signal from an exchange that switches between a voice mode and a 1-link mode, and a high efficiency transmitted from a mobile station. After decoding the coded voice signal into 8-bit PCM, the low-order 2 bits are replaced with a high-efficiency coded voice signal to which a sync pattern is added and output, and an echo generated on the fixed line network side when turned on. An echo canceller that removes and has a data through function when off, an in-channel sync pattern monitoring unit that monitors whether the lower 2 bits of the 8-bit PCM transmitted from the exchange include a sync pattern, and a voice In the mode, the echo canceller is turned on and the echo canceller output is encoded to output a highly efficient encoded audio signal. In the 1-link mode, according to the synchronization monitoring information from the in-channel synchronization pattern monitoring unit, when synchronization is established, the echo canceller is turned off and the high-efficiency coded speech mapped to the lower 2 bits of the echo canceller output. The signal is replaced and output as it is. If synchronization is not established, it is determined that the communication is with a fixed telephone, the echo canceller is turned on, the echo canceller output is encoded, and a high-efficiency encoded voice signal is output. It has an encoder for outputting.

[0023]

According to the present invention, in the 1-link mode, the echo canceller is turned off when the synchronization is established by the synchronization monitoring information from the in-channel synchronization pattern monitoring unit in the 1-link mode. The high-efficiency coded voice signal mapped to the bit is replaced and output as it is. If synchronization is not established, it is determined that the communication is with a fixed telephone, the echo canceller is turned on, and the echo canceller output is encoded. Since a high-efficiency coded voice signal is output after conversion processing, even if the communication between mobile units is transferred to a fixed telephone by call transfer etc., the echo generated in the hybrid circuit is removed to prevent the deterioration of voice quality. In addition, since the in-channel sync pattern monitoring unit constantly monitors the sync pattern, it is possible to After an effect that it is possible to establish immediately synchronization be inclusive data can synchronization pattern.

[0024]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 is a voice processing device. Reference numeral 2 denotes a decoder, which receives the upstream high-efficiency coded voice signal a from the modulator / demodulator and outputs the upstream PCM data b toward the exchange. An echo canceller 3 receives the upstream PCM data b to the exchange and the downstream PCM data c from the exchange, removes the echo generated on the fixed line side when turned on, and has a data through function when turned off. An encoder 4 receives the output d of the echo canceller 3 and the downlink PCM data c from the exchange, and outputs the downlink high-efficiency coded voice signal e to the modem. Reference numeral 5 denotes an in-channel synchronization pattern monitoring unit, which monitors whether or not the lower 2 bits of the downlink 8-bit PCM data c input from the exchange contains a synchronization pattern, and the result is used as synchronization monitoring information f by the encoder. Output to 4. Reference numeral 6 denotes a control signal interface with the exchange, which inputs and outputs a control signal g from the exchange. h is a mode setting signal, and i is an echo canceller on / off switching signal.

The operation of the speech processing apparatus 1 configured as above will be described below. First, when the exchange confirms the call, a signal in which the mode setting signal h is added to the control signal g is sent to the control signal interface 6 of the voice processing device 1. Control signal interface 6
Informs the encoder 4 and the decoder 2 of the operation mode through the mode setting signal h.

The decoder 2 decodes the upstream high-efficiency coded audio signal a in the audio mode and outputs 8-bit PCM as the upstream PCM data b. The upstream PCM data is
It is also input to the echo canceller 3 as a reference value. In the 1-link mode, the upstream high-efficiency coded audio signal a is decoded, 8-bit PCM is obtained, and then the synchronization pattern and the upstream high-efficiency coded audio signal a are mapped to the lower 2 bits and output.

In the voice mode, the encoder 4 turns on the echo canceller 3 by the echo canceller on / off switching signal i, encodes the echo canceller output d, and outputs the downlink highly efficient coded voice signal e. At this time, the echo canceller 3 removes the echo generated in the hybrid circuit of the downlink PCM data c coming from the fixed line network by using the uplink PCM data b as a reference value.
In the 1-link mode, the in-channel sync pattern monitor 5 monitors the sync pattern of the lower 2 bits of the downlink PCM data c and notifies the encoder 4 of the monitor result as sync monitor information f. When synchronization is established, the encoder 4 turns off the echo canceller 3 by the echo canceller on / off switching signal i, and the downlink PC
Echo canceller output d that outputs M data c through
The high-efficiency coded speech signal contained in the lower 2 bits of is replaced as it is, and the downlink high-efficiency coded speech signal e is output. When the synchronization is not established, the echo canceller 3 is turned on by the echo canceller on / off switching signal i, it is determined that the call is with the fixed telephone, the echo canceller output d is encoded, and the high efficiency code is obtained. The converted voice e is output.

As described above, according to the present embodiment, the in-channel synchronization pattern monitoring section 5 monitors the synchronization pattern of the lower 2 bits of the downlink PCM data c and notifies the encoder 4 of the monitoring result as the synchronization monitoring information f. When synchronization is established, the echo canceller 3 is turned off and the high-efficiency coded voice signal mapped to the lower 2 bits of the echo canceller output d is replaced as it is, and the downlink high-efficiency coded voice signal e is output. If the synchronization is not established, it is determined that the communication is with a fixed telephone, the echo canceller 3 is turned on, the echo canceller output d is encoded, and the downlink high-efficiency encoded voice signal e is output. Therefore, even if the communication between mobile devices is transferred to a fixed telephone by call transfer etc., the echo generated in the hybrid circuit is removed. Since the deterioration of voice quality can be prevented and the in-channel synchronization pattern monitoring unit 5 constantly monitors the synchronization pattern, it is possible to immediately establish the synchronization even if the data including the synchronization pattern comes after the synchronization is not established. Have.

[0029]

As described above, according to the present invention, in the 1-link mode, the echo canceller is turned off when the synchronization is established by the synchronization monitoring information from the in-channel synchronization pattern monitoring unit, and the echo canceller is turned off. The high-efficiency coded voice signal mapped to the lower 2 bits of the canceller output is replaced and output as it is. If synchronization is not established, it is determined that the communication is with a fixed telephone and the echo canceller is turned on, Since the echo canceller output is encoded to output a high-efficiency encoded voice signal, even if the communication between mobile units is transferred to a fixed telephone by incoming call transfer, etc., the echo generated in the hybrid circuit is removed and the voice is output. It is possible to prevent deterioration of quality, and because the in-channel synchronization pattern monitoring unit constantly monitors the synchronization pattern, It has an excellent effect that comes the period including a synchronization pattern after not established data can be established immediately synchronize also.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a voice processing device according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a digital mobile communication system in a conventional example.

FIG. 3 is a data bus format between an exchange and a voice processing device in a conventional example.

FIG. 4 is a schematic block diagram of a voice processing device in a conventional example.

[Explanation of symbols]

 1 Voice Processor 2 Decoder 3 Echo Canceller 4 Encoder 5 In-Channel Sync Pattern Monitor 6 Control Signal Interface a Upstream High Efficiency Coded Voice Signal b Upstream PCM Data c Downlink PCM Data d Echo Canceller Output e Downstream High Efficiency Coded Voice Signal f Synchronous monitoring information g Control signal h Mode setting signal i Echo canceller on / off switching signal

Claims (1)

(57) [Claims] 1. A control signal interface for receiving a control signal from an exchange that switches between a voice mode, which is a communication mode of a mobile station and a fixed telephone, and a one-link mode, which is a communication mode of a mobile station to a mobile station in a digital mobile communication system. And a decoder for decoding the high-efficiency coded voice signal transmitted from the mobile device into an 8-bit PCM, replacing the lower 2 bits with the high-efficiency coded voice signal to which the synchronization pattern is added, and outputting the signal. Sometimes the echo generated on the fixed line side is removed, and when it is off, an echo canceller that has a data through function and whether the lower 2 bits of the 8-bit PCM transmitted from the exchange contains a synchronization pattern is monitored. The in-channel sync pattern monitoring unit that operates The canceller output is encoded to output a high-efficiency encoded voice signal, and in the 1-link mode, the synchronization monitoring information from the in-channel synchronization pattern monitoring unit
When synchronization is established, the echo canceller is turned off and the high-efficiency coded audio signal mapped to the lower 2 bits of the echo canceller output is replaced and output as it is, and fixed when synchronization is not established. A voice processing device comprising: an encoder that determines that the communication is with a telephone, turns on the echo canceller, encodes the echo canceller output, and outputs a highly efficient encoded voice signal.