JP3466050B2 - Voice switch for talker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice switch used in a hands-free telephone or the like. In a hands-free telephone that employs a voice switch system, it is necessary to perform continuous conversation control when detecting a sound for performing switch switching control and prevent frequent switch switching.

[0002]

2. Description of the Related Art In order to realize a hands-free function,
It is necessary to increase the speaker volume and microphone sensitivity. However, in this case, as shown in FIG. 4, an acoustic echo occurs in which the received voice output from the voice output unit such as the speaker wraps around to the voice input unit such as the microphone. This is a phenomenon in which one's voice sounds like a echo to the other party of the call, which is extremely difficult to use. In order to remove this acoustic echo, there are two methods: (1) echo canceller method and (2) voice switch method.

The echo canceller system removes acoustic echoes using an adaptive signal processing technique. For example, in FIG.
As shown in (1), an acoustic echo r in which the received voice that is output wraps around the microphone is artificially generated inside the communication device and subtracted from the signal input to the microphone. The generation of the pseudo echo r'is the transfer function from the speaker to the microphone represented by the FIR filter. Since this transfer function changes depending on the surroundings of the telephone, the filter is adaptively changed so as to minimize the error between the pseudo echo r ′ and the acoustic echo r.

On the other hand, in the voice switch system, as shown in FIG. 6, the power of the speaker output voice is compared with the power of the microphone input voice, and one of them is suppressed to remove the acoustic echo. That is, since the signal input to the microphone is an acoustic echo while the speaker is outputting, suppressing the microphone input signal during this period prevents the acoustic echo from being transmitted to the other party.

As described above, there are two methods of removing the acoustic echo, which is a problem in realizing the hands-free function, an echo canceller and a voice switch. The advantages and disadvantages of both are compared as shown in Fig. 7, and there is a trade-off between throughput and capacity. If cost is prioritized, the voice switch system will be adopted. The present invention relates to this voice switch.

FIG. 8 shows a detailed conventional structure of a hands-free telephone equipped with this voice switch. In FIG. 8, reference numeral 1 denotes a receiving unit that includes a demodulator or the like that receives a voice signal from the other party, and 2 denotes a power suppressing unit that can suppress and control the power of the received signal by changing the reception gain gain-r.
Reference numeral 3 is a voice output unit that includes an amplifier, a speaker, and the like and emits a received voice (R). Reference numeral 6 is a voice input section for inputting a voice to be transmitted, which includes a microphone and an amplifier, and 7 is a transmission gain g.
A power suppressing unit that can suppress and control the power of the received signal by changing ain-s, and 8 is a transmitting unit including a modulator that transmits the transmitted voice signal to the other party.

Reference numeral 4 is a power calculation unit for calculating the power of the received signal received by the reception unit 1, and 5'is whether the current received voice state s-r is silent or voiced based on the power calculated by the power calculation unit 4. A sound detector 11 for detecting the sound, a power calculator 11 for calculating the power of the audio signal input to the audio input unit 6, 9 '
Is a voice detection unit that detects whether the current transmission voice state s-s is silent or voice based on the power calculated by the power calculation unit 11, and 10 is the detection result of the voice detection units 5 ′ and 9 ′. It is a determination unit that determines which side of the power suppression units 2 and 7 is to be in the suppression control state based on the above.

Here, the power calculators 4 and 11 calculate the power of the input voice data by the following formula. That is, assuming that the input voice data is x _i , the output power p _i is obtained by p _i = 10 × log [Σ (x _ij × x _ij )]. However, Σ is assumed to be an addition from j = 0 to J.

As shown in FIG. 9, the sound detecting units 5'and 9'include a comparing unit for comparing the input power p _i with a predetermined threshold value th, and the input power p is calculated by the following judgment formula. _i
Is compared with a threshold th to determine whether the current voice state S _i is voiced or silent. Where s _i = 0 is silence, s
_i = 1 means voice. The determination formula is if (p _i <th) s _i = 0 if (p _i > th) s _i = 1. This means that if the input power p _i is smaller than the threshold th, the voice state s _i is “0”, and if it is larger than the threshold th, the voice state s _i is “1”. This prevents background noise equal to or less than the threshold th from being erroneously determined to be voiced.

The determination unit 10 receives the reception gain gai of the reception power suppression unit 2 according to the determination logic table shown in FIG.
It controls the n-r and the transmission gain gain-s of the transmission power suppressing section 7. Here, the reception gain gain-r and the transmission gain gain-s are in the range of 0.0≤gain≤1.0. In the judgment logic table of FIG. 10, when the transmission voice state s−s = 0 and the reception voice state s−r = 0, both the transmission gain gain-s and the reception gain gain-r are “0.0”. Do. When the transmission voice state s-s = 1 and the reception voice state s-r = 0, the transmission gain gain-s is set to "1.0" and the reception gain gain-r is set to "0.0". When the transmission voice state s-s = 0 and the reception voice state s-r = 1, the transmission gain gain-s is set to "0.0" and the reception gain gain-r is set to "1.0". When the transmission voice state s-s = 1 and the reception voice state s-r = 1, the reception gain is prioritized and the transmission gain gain-s is set to "0.
0 ", and the receiving gain gain-r is set to" 1.0 ". Control.

According to the judgment result of the judging section 10, the power is increased.
-The suppression units 2 and 7 are input voice data x _iAgainst
Output audio data x_iOutput as. x_i= X_i× gain

As described above, this voice switch system suppresses one of the received voice and the transmitted voice,
If the other is the received voice, it is output to the speaker, and if it is the transmitted voice, it is transmitted. When both of them are voices, various standards are conceivable, such as the case where the received voice is prioritized and the case where the voice power is higher is prioritized.

[0013]

The voice switch operates at a high speed in order to improve the simultaneous callability as much as possible, but as a side effect, switching may occur in response to a momentary silent portion during a conversation. There is. This causes the conversation partner to switch the switch frequently, so that the other party's voice is heard intermittently, which makes the conversation very difficult to hear and feels uncomfortable.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent frequent switching of switches during a call so that the other party's voice can be kept natural.

[0015]

In order to solve the above-mentioned problems, the voice switch of the telephone set according to the present invention performs the calculation of the power of the reception voice by the reception side power calculation means for calculating the power of the reception voice. A transmitting side power calculating means, and a receiving side voice detecting means for determining a voiced / non-voiced voice state of the receiving voice from the power of the receiving voice of the receiving side power calculating means,
A transmitting side voice presence detecting means for determining a voiced / non-voiced voice state of the transmitting voice from the power of the transmitting voice of the transmitting side power calculating means; and a receiving side suppressing means for suppressing the power of the receiving voice. A transmitting-side suppressing unit that suppresses the power of the transmitting voice, a voice state of the receiving voice determined by the receiving-side voice detecting unit, and a voice state of the transmitting voice determined by the transmitting-side voice detecting unit. A voice-detection means for the receiving side and the transmitting side, and a judging means for judging which of the received voice of the receiving side suppressing means and the transmitted voice of the transmitting side suppressing means is to be suppressed based on the voice state. At least one of the comparison means compares the power of the input voice with a predetermined threshold value and outputs a comparison result indicating whether the voice state at each moment is voiced or silent, and the same voice state is output from the comparison means. The comparison results shown are continuously output for the specified time. Is whether and a determining continuation state determining means configured to output as a determination result of the speech state by the sound detecting means speech state has continued over the predetermined time. In the present invention, in order to prevent frequent switch switching during conversation, a continuous state determination unit that determines how much each of voiced sound and silent sound continues based on a simple comparison result between a threshold value and input voice power. Is provided. The comparison result is silent (or voiced)
It is determined whether or not it continues, and if the same one continues for a predetermined time or more, it is finally determined to be silent (or voiced).

The sound detecting means having the continuation state judging means judges that the voice state is silent when the silent comparison result continues for a first predetermined time or longer, and the sound comparison result is second predetermined time or longer. If the duration of the silent comparison result is shorter than the first predetermined time and the duration of the voice comparison result is shorter than the second predetermined time, the sound state is determined to be sound. It can be configured to maintain the previous determination result of the voice state.

Further, the above-mentioned voice switch can be further provided with a duration changing means for changing the predetermined time used for the continuation state determination by the continuation state determination means to an arbitrary value. By this duration changing means, the user can freely set the duration suitable for the usage environment of the telephone so that a natural call can be made.

In the above voice switch, when the voice detecting section on the receiving side or the transmitting side, which has priority, determines that the voice state is voice, the power calculation and the presence of the voice detecting section on the other side are performed. It can be configured to stop at least one of the sound detection processes. This can reduce unnecessary calculation processing.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a hands-free telephone equipped with a voice switch as an embodiment of the present invention. In the figure, the receiving unit 1, the power suppressing units 2 and 7, the voice output unit 3, the power calculating units 4 and 11, the voice input unit 6, the transmitting unit 8 and the determining unit 10 are circuit elements described in the conventional device of FIG. Since it is the same as, the detailed explanation is omitted here.

On the other hand, the sound detectors 5 and 9 are different from those of the conventional circuit. That is, the sound detecting unit 5 is compared with the comparing unit 51.
The sound detection unit 9 includes a comparison unit 91 and a continuous state determination unit 92. Since the sound detecting units 5 and 9 have the same configuration, only the function and action of the sound detecting unit 5 will be described below.

The comparator 51 is a circuit for comparing the input power signal p _i with a predetermined threshold th, and thereby outputs the comparison result c _{i according} to the following judgment formula.
Here, c _i = 0 means silence, and c _i = 1 means voice.
The determination formula is if (p _i <th) c _i = 0 if (p _i > th) c _i = 1. This means that if the input power p _i is smaller than the threshold th, the comparison result c _i is “0”, and if it is larger than the threshold th, the comparison result c _i is “1”. The comparison result c _i corresponds to the voice state s _i in the conventional device.

Based on the comparison result c _i of the comparing section 51,
The continuous state determination unit 52 determines the voice state s _i . The continuous state determination unit 52 includes a voiced state continuous counter Cnt1 and a silent state continuous counter Cnt0 to which the comparison result c _i is input. This sound state continuation counter Cn
t1 and the silent state continuation counter Cnt0 operate according to the following equation. Input comparison result c _i = 0 → Cnt0 = Cnt0 + 1,
Cnt1 = 0 input comparison result c _i = 1 → Cnt1 = Cnt1 + 1,
Cnt0 = 0 That is, the voiced state continuation counter Cnt1 indicates the comparison result c.
_{When i} = 1 is input, the count value is incremented by 1,
When the comparison result c _i = 0 is input, the count value is reset to 0. The silent state continuation counter Cnt0 indicates the comparison result c _i =
When 0 is input, the count value is incremented by 1, and when the comparison result c _i = 1 is input, the count value is reset to 0.

The determination of the voice state s _i is based on the values of the silent state continuation counter Cnt0 and the voiced state continuation counter Cnt1, and the following judgment expression voice state s _i = 0 if (Cnt0> th0) voice state s _i = 1 if (Cnt1> th1) voice state s _i = s _i−1 if (Cnt0 <th0 and Cnt1 <th1). Here, th0 is the threshold for determining that a voice state s _i is made of sound in silence, th1 is the threshold value for determining that the voice state s _i is made from a silence , "2" in the case of this embodiment
Is set to.

In the above judgment formula, the silent state continuation counter Cnt0 has a predetermined threshold value th.
When it exceeds 0, the voice state s _i = 0, that is, the voice state is silenced, and the voiced state continuation counter Cnt1 has a predetermined threshold value th.
When it exceeds 1, the voice state s _i = 1 is set, that is, the voice state is set, the silent state continuation counter Cnt0 is smaller than the threshold value th0, and the voiced state continuation counter Cnt1 is smaller than the threshold value th1. The voice state s _i-1 which is the determination result is maintained as it is.

FIG. 2 shows an operation example of the determination of the voice state s _i by the apparatus of this embodiment. It is assumed that the comparison result c _i of the comparison unit 51 in the sound detecting unit is, for example, as shown in FIG. In this example, the time t at which the comparison results c _i = 0 continue
From time 1 to time t9, the sporadic sound detection at time t6 (c _i =
1) is performed, and the comparison results c _i = 1 continue for the time t10.
At time t15 and time t19, silent detections (c _i = 0) are made at 24, respectively, and comparison results c _i = 0 continue after time t25. In the conventional device, these times t
The switch is switched even for a single change of 6, t15, and t19, which makes it difficult to hear the conversation.

FIG. 2B shows a silent state continuation counter Cn.
The count value of t0 is shown. Silence continuous counter Cnt
0 continues counting and incrementing each comparison result c _i = 0 continuously until time t4 (count value Cnt0 =
8), the count value Cnt0 = 0 is reset by the comparison result c _i = 1 at the time t6, and then the count of each comparison result c _i = 0 is continued again, and after the time t10, the comparison result c _i = 1 is set. The count value Cnt0 continues to be reset and continues to be "0", but is incremented only when the sporadic comparison result c _i = 0 at time t15 and time t19 to become the count value Cnt0 = 1. Then, after the time t25, the comparison result c _i = 0 is continuously input again, so that the count value Cnt0 is sequentially incremented.

On the other hand, FIG. 2C shows the count value of the sound state continuation counter Cnt1. The sound state continuation counter Cnt1 continues to be reset by each comparison result c _i = 1 until the time t9 and the count value is “0”, but the time t6.
In this case, the count value Cnt1 = 1 is incremented only when the single comparison result c _i = 0. After time t10, each comparison result c _i = 1 is sequentially counted and incremented, but it is reset only when the comparison result c _i = 0 at time t15 and time t19 and the count value Cnt is reset.
1 = 0 and counting is restarted from 0. Time t2
Since the comparison result c _i = 0 continues to be reset after 5, the count value Cnt1 = 0 continues.

Based on the count values of the silent state continuation counter Cnt0 and the voiced state continuation counter Cnt1, the continuation state determination section 52 determines the voice state s _i as shown in FIG. 2 (d). That is, until time t4, the count value of the silent state continuation counter Cnt0 is larger than the threshold value th0 = 2, and therefore the determination is continued as the voice state s _i = 0 (that is, silence). Although at time t5 the count value of the silent state continuation counter Cnt0 is reset to "0", because also the count value of the talk-spurt state continuation counter Cnt1 smaller than the threshold th1 = 2, the speech state s _i in accordance with the foregoing judgment formula The previous voice state s _i-1 = 0 is taken. At time t9, the silent state continuation counter Cnt0 = 3, and therefore the voice state s _i = 0 according to the determination formula. On the other hand, from time t10, the comparison result c
_i = 1, so that the voiced state continuation counter Cnt
1 is incremented, but the count value Cnt1
Is There threshold th1 (= 2) between a smaller, speech state s _i according to the determination expression continues taking the last speech state s _i-1 = 0, the time the talk-spurt state continuation counter Cnt1 = 3 t
Only at 12 is the voice state s _i = 1. Time t15, also the comparison result c _i in time t19 is changed momentarily "0", to keep the previous speech state s _i-1 = 1 according to the same manner as above speech state s _i determination expression. At time t25, the sound state continuation counter Cnt1 = 0 is reset, and the silence state continuation counter Cnt0 starts to be incremented. However, the voice state s _i still has the previous voice state s _i-1 = 1 according to the determination formula. It is maintained, and at time t27 when the silent state continuation counter Cnt0 = 3, the voice state s _i = 0 is determined according to the determination formula.

As described above, in the present embodiment, by providing the continuous state determining unit in the sound detecting unit, it is possible to prevent the switch from being switched in the short sounding part in the silent section or in the short silent section in the sounding section. Realize a natural call.

In the above-mentioned embodiment, the thresholds th0 and th1 for determining the duration for determining the presence / absence of sound are fixed, but the thresholds th0 and th1 can be set arbitrarily. If a means is provided, the predetermined duration used for determining the continuation state can be arbitrarily changed, which allows the user to freely set the duration suitable for the environment in which the telephone is used and to provide a natural and comfortable environment. Can make calls.

FIG. 3 shows another embodiment of the present invention.
Here, the sound detecting units 5 and 9 are the same as those described in the above embodiment. The voice detecting unit 5 on the receiving side notifies the voice detecting unit 9 on the transmitting side and the power calculating unit 11 of the voice state s-r. When it is determined that the voice state s-r of the received voice is voiced, the power calculation unit 11 does not calculate the power of the transmitted voice, and the voice detection unit 9 determines the voice state of the transmitted voice. It is uniquely determined to be silent without making a determination. As a result, the amount of calculation can be reduced, and the load of software processing can be reduced when these processings are performed by software using a microprocessor or DSP.
In this example, it is assumed that the judgment criterion at the time of simultaneous call is the reception priority. Therefore, when the determination criterion for simultaneous call is the transmission priority, the voice detecting section 9 on the transmitting side notifies the voice detecting section 5 on the receiving side to notify the voice state s of the transmitted voice.
When it is determined that -s is voiced, the operations of the power calculation unit 4 and the voiced detection unit 5 on the receiving side may be stopped.

[0032]

As described above, according to the present invention,
It is possible to prevent the switch from being switched due to a short sound in a silent section or a short silence in a sound section, it is possible to prevent the other party's voice from being heard intermittently, and a natural call can be made.

[Brief description of drawings]

FIG. 1 is a diagram showing a hands-free telephone equipped with a voice switch as an embodiment according to the present invention.

FIG. 2 is a diagram showing an operation example of the embodiment apparatus.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram illustrating acoustic echo in a hands-free telephone or the like.

FIG. 5 is a diagram illustrating an echo canceller system.

FIG. 6 is a diagram illustrating a voice switch system.

FIG. 7 is a diagram comparing an echo canceller method and a voice switch method.

FIG. 8 is a diagram showing a conventional hands-free telephone equipped with a voice switch.

FIG. 9 is a diagram showing a configuration of a sound detecting unit in a conventional device.

FIG. 10 is a diagram showing an example of a voiced / unvoiced determination table.

[Explanation of symbols]

1 receiver 2, 7 Power suppression unit 3 Audio output section 4, 11 Power calculator 5, 5 ', 9, 9'Sound detection unit 6 Voice input section 8 transmitter 51, 91 Comparison section 52, 92 Continuation state determination unit

Front page continued (72) Inventor Hiroshi Katayama 4-1-1 Kamitadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (72) Insei Inori Kimura 3-22-22, Hakataekimae, Hakata-ku, Fukuoka, Fukuoka Issue: Fujitsu Kyushu Digital Technology Co., Ltd. (56) References JP-A-6-78046 (JP, A) JP-A-7-95272 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04M 1/60 H04B 3/23

Claims (4)

(57) [Claims] 1. A receiving side power calculating means for calculating the power of a receiving voice, a transmitting side power calculating means for calculating a power of a transmitting voice, and a receiving voice power from a receiving voice power of the receiving side power calculating means. Receiving side voice detecting means for determining a voiced / non-voiced voice state, and a transmitter side for determining a voiced / non-voiced voice state of the transmitted voice from the power of the transmitted voice of the transmitter side power calculation means Sound detecting means, receiving side suppressing means for suppressing the power of the receiving voice, transmitting side suppressing means for suppressing the power of the transmitting voice, and voice of the receiving voice determined by the receiving side voice detecting means It is determined which of the received voice of the receiving side suppressing means and the transmitting voice of the transmitting side suppressing means is to be suppressed based on the state and the voice state of the transmitting voice determined by the transmitting side voice detecting means. Determination means, and the receiving side And at least one of the sound detecting means transmitting side compares the power of the input speech with a predetermined threshold value,
Outputs the comparison result indicating whether the voice state at each moment is voiced or silent
And a ratio indicating the same voice state from the comparing means.
Compare results and a continuation condition determining means for determining whether the continuously output for a predetermined time, the predetermined time
The voice state that continues over the
A voice switch of a telephone set configured to output as a determination result of a voice state . Wherein said continuous condition determination hand stage, silence comparison result is judged to continue to silence the sound state When for a first predetermined time or more, when the sound of the comparison result continues over a second predetermined time or more If the voice state is determined to be voiced and the duration of the silent comparison result is shorter than the first predetermined time and the duration of the voice comparison result is shorter than the second predetermined time, the previous voice The voice switch for a telephone set according to claim 1, wherein the voice switch is configured to maintain the determination result of the state. 3. A further voice switch according to claim 1 or 2, wherein the call unit with a duration time changing means for changing the predetermined time to any value to be used for continuation state determination in the continuous state determining means. 4. When the voice detecting means on the receiving side or the transmitting side, which has priority, determines that the voice state is voiced, at least power calculation and voice detecting processing of the voice detecting means on the other side. Claims 1 and 2 configured to stop one
Or the voice switch of the telephone set described in 3.