JP5384206B2 - High quality telephone equipment with high frequency noise reduction function - Google Patents

Description

  The present invention relates to ambient noise reduction during a non-call period in a high-quality telephone device with a wide voice band.

  The voice band of a normal telephone is 3.4 kHz. However, as the line becomes broadband, the telephone voice is also becoming wider (for example, 7 kHz) and higher in sound quality. As the voice becomes wider, it is particularly desirable to reduce high-frequency noise.

  As a noise reduction technique in conventional telephone devices, by monitoring the ambient noise using a microphone, when a certain level of sound pressure is not input, the voice in the transmission is cut, and more than a certain level There is a technique for reducing the influence of ambient noise during a call by performing processing such as transmitting voice to the other party when a pressure is input. (For example, see Patent Document 1)

JP 2006-287431 A

  In the above-mentioned Patent Document 1, by monitoring ambient noise using a microphone, when a certain level of sound pressure is not input, the voice in transmission is cut, and a sound pressure exceeding a certain level is input. In this case, processing such as transmitting the voice of the transmission to the other party can reduce the effect of ambient noise during the phone call on the device, but the sound rise and sound repellent are effective from silence. In the case of a sound, the first part of the beginning sound until the predetermined threshold value for detecting the sound is lost is lost, making it difficult for the other party to hear the voice of the transmission during the call. There was a problem that it was a call.

  In addition, for example, when a call is made using a low-frequency side audio band of 0 Hz to 3.4 KHz band and a high-frequency side audio band of 3.4 KHz or higher, the call partner is only during transmission. In addition, there is a problem of transmitting high-frequency noise to the other party even when not transmitting.

The above-described problem is that in a high-quality telephone device having a wide-band voice input means, the voice signal collected from the voice input means is checked for sound or silence to detect the input voice signal level, Depending on whether the voiced level or the silent level has continued for a predetermined time, it is determined whether or not the own telephone device is transmitting, and the voice input unit collects the sound and converts it into an electrical signal. High band side cut means for cutting the high band side voice band of the speech voice signal, and information determined by the call band determination unit in the call control unit during the call is notified to the control unit, and the broadband call state or the normal band call state a passband determining means for performing Kano determination, either the transmitted voice signal is high-frequency side voiceband of the audio signal higher frequency audio band is cut by the audio signal or the high frequency side cutoff means of the original sound is not cut Anda transmitter switching means for switching to, by performing the determination of whether a call, if it is determined that a call, the determination of whether the normal band call state wideband speech state by the passband determining means And when the call band determining unit determines that the normal band call state is in effect, the transmission switching unit is controlled so that the high band side cut is performed regardless of the detection result by the transmitting determination unit. It sends a transmission voice signal unit has cut the high-frequency side voice band, when it is determined that the wideband speech state by the passband determining means said transmitter in determining means self telephone device transmitter When it is determined that the transmission is in progress, the transmission switching means is controlled so that the high frequency cut means transmits a transmission voice signal that does not cut the high frequency voice band, and the mid transmission determination means The phone device has determined that it is not transmitting The case, the transmitter switching means to control the height region side cutting means transmits a transmission audio signal cuts the high-frequency side voiceband, then performs determination of whether a call end, end If it is not a talk, it can be achieved by repeating the determination of whether the communication state is a broadband call state or a normal band call state by the call band determining means .

  ADVANTAGE OF THE INVENTION According to this invention, the high quality telephone apparatus which reduced the ambient noise in the non-call period without impairing the telephone call quality by the broadband call in a high quality telephone apparatus can be provided.

FIG. 1 is an overall configuration diagram of a high-quality telephone device having a high-frequency noise reduction function according to an embodiment of the present invention. FIG. 2 is a diagram showing the frequency characteristics of the input voice signal in the voice band of the low frequency side voice band and the high frequency side voice band of the high sound quality telephone apparatus of the present invention. FIG. 3 is an operation flowchart of the high sound quality telephone apparatus according to the embodiment of the present invention. FIG. 4 is a diagram showing a specific example of a change in the input voice signal at the time of determination during transmission according to the embodiment of the present invention. FIG. 5 is an operation flowchart of a specific example of determination during transmission according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram of a high-quality telephone device having a high-frequency noise reduction function according to an embodiment of the present invention. FIG. 2 is an operation flowchart in the high sound quality telephone apparatus having a high frequency noise reduction function.

  As shown in FIG. 1, the high sound quality telephone device 1 includes a microphone 2, a speaker 3, and a user operation display unit 4.

  Here, in the high sound quality telephone device 1, the line interface unit 11, the call control unit 12, the control unit 13, the mid-transmission determination unit 14, the high-frequency cut filter unit 15, and the transmission switch unit 16 The level adjustment units 17 and 18 are composed of an encoding unit 19 and a decoding unit 20.

  When there is an incoming call notification from the line, the line interface unit 11 and the call control unit 12 notify the control unit 13 that there is an incoming call notification, shift to the incoming call operation, By notifying by LED lighting display, the user is notified that there is an incoming call. When a user performs a call operation, the user operation display unit 4 notifies the control unit 13 of the state of the apparatus and shifts to a call operation.

  Here, for the voice band in the call, information determined by the call band determination unit 21 in the call control unit 12 is notified to the control unit 13 to detect the call band. In FIG. 1, the call bandwidth determination unit 21 is provided in the call control unit 12, but may be configured separately from the call control unit 12.

  The audio signal in the transmission collected by the microphone 2 is not cut by the high frequency cut filter unit 15, for example, the audio signal from which the high frequency side audio band of 3.4 kHz or higher is cut and the high frequency side audio band are not cut. The original sound is divided into two audio signals.

  When the control unit 13 determines that the normal band call state is in accordance with the notification of the call band from the call band determination unit 21 of the call control unit 12, the transmission from the microphone 2 is performed when the call state is changed. Regardless of the detection result by the mid-sending determination unit 14, the transmission switching unit 16 is switched to the B side, the high frequency side of the original sound from the microphone 2 is cut, and the level adjustment unit 17, The data is transmitted to the other party via the line interface unit 11 via the encoding unit 19.

  Here, when it is determined by the control unit 13 that the communication state is in the broadband communication state based on the notification of the communication band from the communication band determination unit 21 of the call control unit 12, the in-transmission determination unit 14 is transmitting. If it is determined that there is, the transmission switching unit 16 is switched to the A side, the original sound from which the high frequency side audio band from the microphone 2 is not cut is selected, and the level adjustment unit 17 and the encoding unit 18 are passed through. Then, the data is transmitted to the other party through the line interface unit 11.

  In addition, when the transmission determining unit 14 determines that it is during the non-transmission period, the transmission switching unit 16 is switched to the B side, and the high-frequency cut filter unit 15 performs the operation at 3.4 kHz or higher. An audio signal from which the high frequency side audio band has been cut is selected and transmitted to the other party via the line interface unit 11 via the level adjustment unit 17 and the encoding unit 19.

  As a result, a broadband call is realized when the call is being sent to the other party of the call, and an audio signal obtained by cutting the high frequency side audio band of 3.4 KHz or more is cut during the non-call period. By sending it out, it is possible to send out the transmitted voice with reduced high-frequency noise.

  With respect to the voice signal in the incoming call, the voice signal received from the line via the line interface unit 11 can be decoded by the decoding unit 20, adjusted in level by the level adjusting unit 18, and then listened to by the speaker 3. .

  FIG. 2 shows the frequency characteristics of the input voice signal in the voice band of the low frequency side voice band and the high frequency side voice band of the high sound quality telephone apparatus of the present invention. Note that a description is given on the assumption that the voice band up to 3.4 KHz, which is a voice band in a normal telephone, is set as the low frequency side, and 3.4 kHz or higher (here, up to 7 kHz) is set as the high frequency side.

Input audio signal, and the low frequency side voiceband of 0Hz～3.4KHz, is capable of handling high-frequency audio band above 3.4 kHz, when detecting an audio transmission, the low band from the microphone 2 High-quality audio signals in the audio band including the high-side audio band and the high-frequency side audio band are transmitted to the other party of the call. Send to the other party. Therefore, the low frequency side audio band is always reproduced, and the high frequency side audio band including the annoying high frequency side noise is cut during the non-transmission period.

  FIG. 3 is an operation flowchart of the high-quality telephone device according to the embodiment of the present invention. In FIG. 3, the high sound quality telephone device 1 determines whether or not a call is in progress (S101). If it is determined that a call is in progress, it is determined whether the call is in a broadband call state or a normal band call state (S102).

  When it is determined that the state is a broadband call state (S102, Yes), the voice signal collected from the microphone is subjected to voice / silence detection (S103) to confirm the input voice signal level, and the voice level / It is determined whether or not the transmission is in progress (S104) depending on whether or not the silence level has continued for a predetermined time.

  If it is determined whether or not the transmission is in progress (S104, Yes), the audio signal collected from the microphone is compared with the low frequency side audio band for the other party of the call. It is transmitted in the same voice band including the high frequency side voice band.

  Further, when it is determined in the determination of whether or not the transmission is in progress (S104), it is determined that the non-transmission period is in progress (No in S104), the high-frequency cut filter unit 15 determines the high-frequency side audio band. The cut audio signal is sent to the other party of the call.

  The high sound quality telephone device 1 returns to step S101 if the call is ended (S106, Yes), and returns to step S102 if the call is not ended (S106, No). Return.

According to the present embodiment, it is possible to remove the noise component on the high frequency side during non-transmission in which the silent state continues without installing special hardware, and whether or not it is during the non-transmission period. Since the low frequency side voice in the same band as that of a normal telephone is always transmitted, the beginning sound at the time of detecting the voice is not lost and the conversation is not impaired.

  That is, when a call is being sent to a call partner, a broadband call is realized, and when the call is not being sent, a high-frequency side voice band of 3.4 KHz or higher is cut. It is possible to reduce the transmission of high-frequency noise during non-transmission and to provide a device with excellent call quality that can be easily heard by the other party.

  FIG. 4 is a specific example showing a change in the input voice signal at the time of determination during transmission according to the embodiment of the present invention. In FIG. 4, it is determined whether the input voice signal is greater than or equal to a predetermined value VTH. When the input audio signal is smaller than the predetermined value VTH, there is no sound.

When the input voice signal becomes larger than the predetermined value VTH, the silent state is canceled and the transmission period is started.
However, even if the input audio signal becomes smaller than the predetermined value VTH and becomes silent, it is not immediately determined as a non-transmission period. In the determination of the non-sending period in the embodiment of the present invention, it is determined that the silent state has shifted to the non-sending period for the first time when the silent state continues for the predetermined period T0.

  For example, at the time t1 in FIG. 4, the silent state is changed to the voiced state, and the transmitting period starts. At time t2, the sound state shifts to the silent state. In this case, since the silent period (t2 to t3) is shorter than the predetermined period T0, it is determined that the transmission period is continued. Moreover, although it changes to a silent state from a sound state also at the time t4, since the silent period (t4-t5) is shorter than predetermined period T0, it determines with the period during transmission continuing.

  On the other hand, when a transition is made from the voiced state to the silent state at time t6 and this silent period continues until time t7, and the silent period (t6 to t7) reaches the predetermined period T0, the mid-transmission period ends. Then, it is determined that the period has been shifted to the non-transmission period, and an audio signal with the high frequency side audio band cut is transmitted to the other party of the call.

  Thereafter, when the silent state is changed to the voiced state at time t8, it is determined that the non-sending period is ended and the transmitting period is started. In addition, when changing from the non-sending period to the transmitting period, the voiced state may be changed to determine that the non-sending period has changed to the transmitting period for the first time after a certain period of time. Is possible.

  FIG. 5 is an operation flowchart showing a specific example of determination during transmission according to the embodiment of the present invention. In FIG. 5, when the operation for determination during transmission is started, it is determined whether or not the input voice signal level is higher than the predetermined value VTH (S1041). If the input voice signal level is higher than the predetermined value VTH (S1041). , Yes), a transition is made to the broadband call state (S1042), the transmission switching unit 16 in FIG. 1 is switched to the A side, and the original sound whose high frequency side voice band is not cut is selected to be the other party of the call Then, the process proceeds to step S106 in FIG.

  If the input audio signal level is equal to or smaller than the predetermined value VTH (S1041, No), it is determined whether the silent period is longer than the predetermined period T0 (S1041). When the silent period is longer than the predetermined period T0 (S1043, Yes), the process shifts to the high frequency cut state (S1044), the transmission switching unit 16 in FIG. The voice signal whose voice band is cut is selected and transmitted to the other party, and then the process proceeds to step S106 in FIG.

  When the silent period is not longer than the predetermined period T0 (S1043, No), the state shifts to the high frequency cut state (S1045), the state where the transmission switching unit 16 in FIG. A high sound quality audio signal whose voice band is not cut is selected and transmitted to the other party, and then the process proceeds to step S106 in FIG.

  The high sound quality telephone apparatus having the high frequency noise reduction function of the present invention can be applied to a high sound quality telephone apparatus that processes a voice band of 3.4 kHz or higher (for example, 7 kHz). Further, the present invention is not limited to the normal telephone voice band of 3.4 KHz, but can be applied to various voice communication apparatuses that divide the voice band into a plurality of voice bands and reduce noise in the high frequency side voice band.

DESCRIPTION OF SYMBOLS 1 High sound quality telephone apparatus 2 Microphone 3 Speaker 4 User operation display part 11 Line | wire interface part 12 Call control part 13 Control part 14 In-transmission determination part 15 High frequency cut filter part 16 Transmission switching part 17 Level adjustment part 18 Level adjustment part 18 Level adjustment part 19 Encoding unit 20 Decoding unit 21 Call band determination unit

Claims (1)

In a high-quality telephone device having a broadband voice input means,
The voice signal collected from the voice input means is subjected to voice or silence detection to confirm the input voice signal level, and depending on whether or not the voice level or silence level continues for a predetermined time, A mid-transmission judging means for judging whether or not
High-frequency side cut means for cutting the high-frequency side audio band of the transmission voice signal collected by the voice input means and converted into an electrical signal;
Information determined by the call band determining unit in the call control unit during a call is notified to the control unit, and a call band determining unit for determining whether the state is a broadband call state or a normal band call state;
Yes and a transmitter switching means for switching to one of the audio signals the high-frequency side voice band is cut by the audio signal or the high frequency side cutoff means of the not transmitted voice signal cut higher-frequency speech bands original And
It is determined whether or not a call is in progress, and if it is determined that a call is in progress, a determination is made as to whether the call band determination means is in a broadband call state or a normal band call state,
When it is determined by the call band determining means that the normal band call state is in effect, the high frequency side cut means controls the transmission switching means so that the high band side cut means is irrelevant to the detection result by the mid-transmission determining means. Sending the transmission voice signal that cuts the high frequency side voice band,
If it is determined by the call band determination means that the state is a broadband call state,
When the mid-sending determination means determines that the telephone apparatus is transmitting, the high-side cut means controls the transmission switching means so that the high-frequency side cut means does not cut the high-frequency side audio band. Send a signal,
When the mid-transmission determining means determines that the telephone apparatus is not transmitting, the high-side cut means controls the transmission switching means and the high-frequency side cut means cuts the high-frequency side audio band. Send a signal ,
Thereafter, it is determined whether or not the call is ended, and if the call is not ended , a high-frequency noise reduction function is characterized in that the call band determining means repeatedly determines whether the call is in a broadband call state or a normal band call state. Having a high sound quality telephone device.

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