JP4512066B2 - Telephone - Google Patents

Description

  The present invention relates to a telephone, and more particularly to an IP telephone having an echo canceller that removes echo generated by a communication line.

  In recent years, IP (Internet Protocol) telephones using the Internet have been rapidly spread, and in this IP telephone, voices uttered by the users themselves on the transmission side wrap around the subscriber lines in a two-wire / four-wire hybrid configuration. Thus, there is a problem of generating so-called echo. In order to remove this echo, Patent Document 1 discloses a technique in which an echo canceller is provided in an IP telephone.

  Further, referring to Patent Document 2, when canceling echo by an echo canceller in an IP telephone, it is possible to effectively cancel echo by performing learning control for echo cancellation in a short time using an internal tone signal. Such a technique has been proposed.

  Further, referring to Patent Document 3, when canceling an echo, a signal from a basic signal generation circuit is output on an audio signal path to detect a signal level on the path, and based on the detection result. A technique for automatically adjusting the audio signal level is disclosed.

Japanese Patent Laid-Open No. 11-8696 JP 2004-32457 A JP 2002-51142 A

  When an analog line is used for an IP telephone using a PBX or other connection device, the voice quality may be significantly deteriorated due to the delay of the IP telephone and the reflection and loss of the analog line. Therefore, an echo canceller as shown in Patent Document 1 is used. In such an echo canceller, a transmission signal from an IP telephone is sampled and the received signal of the other party is detected based on the data. Filtering is performed to remove only echoes from the call signal.

  In the techniques of Patent Documents 2 and 3, the frequency is learned for each call and the echo is removed, but there is a problem that it is not possible to cope with the remaining echo and the call signal clipping due to an increase or decrease in gain. . Further, at the time of shipment or installation, a certain amount of gain adjustment is possible, but it is difficult to make adjustments according to the call destination. This is because there are various combinations of the other party's system and terminal, and the level of echoes on the incoming call and the incoming call changes depending on each of these factors.

  Furthermore, since the transmission level that changes depending on the individual difference of IP telephone users is also a factor that affects the performance of the echo canceller, it is impossible to eliminate clipping of the call by completely removing the echo from the call signal. .

  An object of the present invention is to provide a telephone with an echo canceller that allows a user of an IP telephone to easily adjust a voice quality level suitable for the user during a call.

The telephone according to the present invention is
Echo removing means for removing echo generated by the communication line ;
A telephone including a gain adjusting means for adjusting a gain for a call signal in response to a user operation ,
The gain adjusting unit is configured to adjust an amplifier gain for each of an input signal and an output signal of the echo removing unit, and a total gain for the input signal and the output signal is constant .

Then, the gain adjusting means is provided in the user interface unit, characterized in that it is a volume for gain adjustment to the call signal.

Further, the present invention further comprises storage means for storing the gain setting amount of the gain adjusting means in correspondence with the call destination, and the gain adjustment means corresponds to the gain set amount corresponding to the call destination during a call. Is stored in the storage means, the gain adjustment is performed based on the stored gain setting amount.

  The operation of the present invention will be described. If there is concern about the echo remaining in the call state, the user adjusts the gain of the call signal input to the echo canceller using the adjustment volume, and at the same time, reverses the output signal from the echo canceller. The gain is adjusted in the direction (the total gain for the call signal remains constant without changing). At this time, by storing the gain setting amount corresponding to the calling party in the memory, the gain setting amount can be read from the memory and automatically adjusted during the subsequent call to the same calling party. .

  According to the present invention, it is possible to easily change the call quality level suitable for the user by adjusting the gain of the user himself / herself by providing the function for adjusting the gain of the transmission / reception in the user interface. In addition, by saving the gain setting for each call partner, there is an effect that optimum call quality can be obtained without readjustment.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic functional block diagram of an IP telephone to which an embodiment of the present invention is applied. In FIG. 1, an IP telephone 10 is connected to a WAN network via a LAN network 17 and a router 16. The IP telephone 10 includes a central control circuit 11 including a CPU that controls each unit, a memory 12 that stores data, a user interface circuit 13 that includes operation buttons, and an audio signal control circuit that performs audio signal conversion and gain adjustment. 14 and a LAN interface 15 for communicating with the LAN 17.

  FIG. 2 is a functional block diagram of an embodiment of the present invention, which is included in the audio signal control circuit 14 shown in FIG. Referring to FIG. 2, the reception signal IN is input to the echo canceller circuit 5 through the amplifier 1, is echo-cancelled, and is derived as the reception signal OUT through the amplifier 2. The transmission signal IN is input to the echo canceller circuit 5 via the amplifier 4 and becomes a signal for echo cancellation, and is derived as the transmission signal OUT. Note that the echo canceller circuit 5 has a well-known configuration, and shows an echo cancel circuit using a technique of sampling (51) the transmission signal IN and filtering (52) the reception signal IN.

  A volume 6 for adjusting the gain of the amplifiers 1 and 2 for received signals and a volume 7 for adjusting the gain of the amplifiers 3 and 4 for transmitting signals are provided. These volumes 6 and 7 are provided in the user interface 13 so that the user can manually adjust them.

  FIG. 3 is a flowchart showing the operation of the embodiment of the present invention. First, when a call is established using an IP telephone according to the present invention and a call is established (step S0), the previous set content or initial value is read from the memory from the call number (or call ID) (step S1). .

  Next, when the user of the IP telephone determines that the gain adjustment is necessary (step S2), the user selects whether to adjust by sending or receiving (step S3). If it is determined that adjustment by reception is necessary, the reception gain adjustment volume 6 in FIG. 2 is used (step S4), and adjustment is performed (steps S6, S8 to S11). If it is determined that adjustment by transmission is necessary, the transmission gain adjustment volume 7 in FIG. 2 is used (step S5) and adjustment is performed (steps S7, S12 to S15).

  For example, when “gain increase” is instructed by the operation of the volume 6, the amplifier 1 amplifies the signal according to the instruction of the volume (step S8), and the amplifier 2 attenuates the signal by the same amount as the amplification of the amplifier 1. Is performed (step S9). On the contrary, when “gain reduction” is instructed by the operation of the volume 6, the amplifier 1 attenuates the signal according to the instruction (step S10), and the amplifier 2 amplifies the signal by the same amount as the attenuation of the amplifier 1. Is performed (step S11).

  Similarly, when “gain increase” is instructed by the operation of the volume 7, the amplifier 4 amplifies the signal in accordance with this instruction (step S12), and the amplifier 3 attenuates the signal by the same amount as the amplifier 4 amplification. Is performed (step S13). On the contrary, when “gain reduction” is instructed by the operation of the volume 7, the amplifier 4 attenuates the signal according to the instruction (step S14), and the amplifier 3 amplifies the signal by the same amount as the attenuation of the amplifier 4. Is performed (step S15).

  If the call quality is not improved by the above operation, the processing from step S3 to step S15 is repeated (step S16). When the call quality is improved, the call destination (calling number or calling ID) and the gain setting value of each amplifier are stored in the memory (step S17).

  By doing so, it is possible to change only the level of the signal applied to the echo canceller circuit 5 without changing the total level of both the transmission / reception signals. Then, by performing the above operation by the user himself, the setting of the echo canceller can be adjusted with the same feeling as changing the volume of the call, and can be changed to an optimal setting suitable for the situation at that time. Further, by storing the gain setting value for each call partner in the memory, the optimum call quality is automatically made without the need for readjustment at the next and subsequent calls.

1 is a schematic functional block diagram of an IP telephone to which an embodiment of the present invention is applied. It is a block diagram of the Example of this invention. It is a flowchart which shows operation | movement of the Example of this invention.

Explanation of symbols

1-4 Amplifier 5 Echo canceller circuit 10 IP telephone 11 Central control circuit 12 Memory 13 User interface 14 Voice signal control circuit 15 LAN interface circuit 16 Router 17 LAN network

Claims (4)

Echo removing means for removing echo generated by the communication line ;
A telephone including a gain adjusting means for adjusting a gain for a call signal in response to a user operation ,
The telephone according to claim 1, wherein the gain adjusting means is configured to adjust an amplifier gain for each of an input signal and an output signal of the echo removing means, and a total gain for the input signal and the output signal is constant . 2. The telephone set according to claim 1, wherein the gain adjusting means is provided in a user interface unit and is a gain adjusting volume for the call signal. 3. The telephone set according to claim 1 , further comprising storage means for storing a gain setting amount of the gain adjusting means in correspondence with a call destination . The gain adjusting means adjusts the gain based on a stored gain setting amount when a gain setting amount corresponding to a call destination is stored in the storage means during a call. The telephone set according to claim 3 .

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