JPH07321729A - Communication equipment - Google Patents

Abstract

PURPOSE:To provide a sound field listened truly, easily by the user by adjusting and keeping automatically a state of a received sound to a proper state at all times against surrounding environment in the communication equipment such as a mobile telephone system. CONSTITUTION:A sound volume adjustment section 41 adjusting the level of a reception signal and a frequency characteristic adjustment section 42 adjusting the frequency characteristic are provided to a transmission line for the reception signal subjected to electroacoustic conversion through a handset 6 or a loudspeaker 7. On the other hand, an adaptive filter 51 suppressing an echo at hand-free talking is provided to a transmission line of a transmission signal subjected to acoustoelectric conversion by a hand-free microphone 8. Then a noise sound level in a cabin and its frequency characteristic are estimated based on detected information by various sensors 43 such as car velocity sensor and acceleration sensor and the adjustment quantity of the signal level and the frequency characteristic is controlled by the sound volume adjustment section 41 and the frequency characteristic adjustment section 42 so that the received sound is protected from noise sound or echo.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone mounted on a moving body such as an automobile, a train, an aircraft or a ship, or a telephone installed in a relatively noisy environment such as a factory,
Further, the present invention relates to a call device suitable for use in a mobile phone or the like.

[0002]

2. Description of the Related Art In recent years, in these telephones, especially car telephones, in addition to a general telephone call system using a handset, a so-called hand-free telephone call system using a loudspeaker and a hand-free microphone is provided. It is becoming popular.

However, in such a voice communication system represented by hands-free communication in the vehicle compartment, the SN ratio (S / N) of the received sound due to ambient noise is lower than that in a communication system using a handset. Is big. Therefore, in order to compensate for such a decrease in S / N, the user has to adjust the listening volume each time the degree of ambient noise changes.

Therefore, conventionally, for example, Japanese Patent Laid-Open No. 4-4014 is used.
A telephone with an automatic volume control as described in Japanese Patent No. 2 has been proposed. By the way, in the telephone described in the publication, a microphone for background noise measurement is provided separately from the microphone for transmission, and the reception sound is received according to the ambient noise level measured by the microphone for background noise measurement. The volume of is automatically adjusted. That is, when the ambient noise and noise levels are high, the output level of the receiving speaker of the telephone is also high, so that the listening volume can be ensured in an environment with such noise and noise.

[0005]

As described above, if the ambient noise level is measured through the background noise measuring microphone and the volume of the received sound is automatically adjusted, the user needs to adjust the volume one by one. The convenience as a telephone is certainly improved.

Further, since the volume of the received sound is increased when the ambient noise and the noise level become high, the audibility of the received sound is certainly improved to some extent. However, according to the above conventional telephone, it is indispensable to provide such a microphone for background noise measurement in order to obtain its convenience. Therefore, some problems remain in terms of cost and installation space.

Furthermore, the easiness of hearing the received sound depends not only on the volume difference between the received sound and the ambient noise, but also on the frequency characteristics of the surrounding sound field. This is because the volume of the received sound is increased. However, the sound is not always easy to hear.

Here, the problem has been taken up on the premise of a loudspeaking communication system represented by hands-free communication. However, in the case of a telephone used in an environment with a large amount of ambient noise and noise, it depends on the handset. Even in a general telephone system, such a situation remains unchanged.

Further, particularly in a hands-free call, in an environment where a voice is easily circulated from the loudspeaker to the hands-free microphone, that is, an environment where an echo is likely to occur, in addition to the above-mentioned ambient noise,
The deterioration of the received sound due to the echo cannot be ignored.

The present invention has been made in view of these circumstances, and automatically adjusts and maintains the state of the received sound to an appropriate state with respect to the surrounding environment, and truly listens to the user. An object is to provide a communication device that can provide an easy sound field.

Further, the present invention provides a speech communication system capable of suitably suppressing the above-mentioned echo and eventually avoiding the influence of the echo on the received sound in a voice communication system such as hands-free communication. The purpose is to provide.

[0012]

In order to achieve such an object, the invention according to claim 1 has a handset for making a call, and transmits a voice signal which is voice-electrically converted by the handset. In a communication device that transfers to the other party as a speech signal, captures a voice signal transferred from the other party as a reception signal, and converts this into an electric-speech by the same transmitter / receiver, it is arranged in the transmission line of the reception signal and the reception Volume adjusting means for adjusting the signal level of the signal, frequency characteristic adjusting means also arranged in the transmission path of the receiving signal to adjust the frequency characteristic of the receiving signal, and noise around the handset or a parameter corresponding to the noise. A noise information sensor for detecting noise information, and a voice that is electrically-voice-converted by the handset based on the detected noise information is protected from this noise. Ku, a structure comprising, respectively and control means for controlling at least one adjustment amount of the frequency characteristic due to the signal level of the adjustment amount and the frequency adjusting means according to said volume control means.

According to the second aspect of the present invention, in such a communication device, the handset has a hands-free microphone that performs voice-electric conversion to generate the transmission signal, and at least one of the signal level and the frequency characteristic. Having a hands-free device with a loudspeaker for converting the received signal adjusted to electric-speech,
The communication device is a filter that is disposed between the loudspeaker and the handsfree microphone and suppresses an echo component of a voice converted by the loudspeaker from a transmission signal electrically converted by the handsfree microphone. Further means shall be provided. Then, the control means is configured to control at least one of the adjustment amount of the signal level by the volume adjusting means and the adjustment amount of the frequency characteristic by the frequency adjusting means with reference to the suppressed residual echo as well.

According to a third aspect of the present invention, in such a communication device, the control means includes the signal level adjustment amount by the volume adjustment means and the frequency adjustment means so that the level of the residual echo is minimized. It is configured to control at least one of the adjustment amounts of the frequency characteristics.

Further, in the invention as set forth in claim 4, in the same communication device, the transmitter / receiver includes a transmission path of a reception signal between the volume adjusting means and the frequency characteristic adjusting means and the filter means, and the filter. It is further assumed that the mobile phone further includes a handset in which the electric-voice converting means and the voice-electric converting means are connected to the transmission path of the transmission signal between the means and the control means via the switch means, respectively. And
The control means is configured to cancel the reference of the residual echo when the handset is switched to the handset side by the switch means.

In the invention according to claim 5, when these communication devices are mobile telephone devices mounted on a moving body, the noise information sensor is a speed sensor or an acceleration sensor mounted on the moving body. And one or more of the noise sensors.

Further, in the invention according to claim 6, in these control devices, the signal level adjustment amount and the frequency adjustment by the volume adjusting means corresponding to various noise levels and various sound field frequency characteristics around the handset are adjusted. Having a control pattern memory in which the adjustment amount of the frequency characteristic by the means is registered in advance as a control pattern, and reading out a corresponding control pattern from the control pattern memory based on the noise information at each time detected by the noise information sensor Configure as.

Further, according to the invention of claim 7, there is provided a hands-free device in which a hands-free microphone and a loudspeaker are separately arranged, and a voice signal which is voice-electrically converted by the hands-free microphone is transmitted. In a communication device which transfers a voice signal transferred from the other party as a transmission signal, takes in a voice signal transferred from the other party as a reception signal, and converts this into an electric voice by a loudspeaker A volume adjusting means for adjusting the signal level of the signal, a frequency characteristic adjusting means for adjusting the frequency characteristic of the received signal similarly arranged in the transmission path of the received signal, and a frequency characteristic adjusting means for distributing between the loudspeaker and the hands-free microphone. Is installed and the sound is transmitted from the loudspeaker from the transmission signal electrically converted by the hands-free microphone. Filter means for suppressing the echo component of the converted voice, and at least one of the adjustment amount of the signal level by the volume adjusting means and the adjustment amount of the frequency characteristic by the frequency adjusting means with reference to the suppressed residual echo And a control means for controlling each of them.

Further, in the invention as set forth in claim 8, in such a structure as an echo canceller, the control means controls the signal level adjustment amount and the frequency by the volume adjusting means so that the level of the residual echo is minimized. It is configured to control at least one of the adjustment amounts of the frequency characteristics by the adjusting means.

[0020]

According to the invention described in claim 1, based on the noise information detected by the noise information sensor (for example, volume information of ambient noise, frequency characteristic information of the same sound field, etc.), the received sound is derived from those noises. In a protected manner, the volume of the received voice, the frequency characteristic, or both are automatically adjusted. For example, in this adjustment mode, (1) when the volume of noise is relatively low, the volume of the received sound is increased. (2) Even if the volume of noise is large, if the frequency band is limited to a certain range, the frequency characteristic of the received sound is shifted so that the frequency band is out of this specific range. At the same time, the volume of the received sound may be increased. (3) When the volume of noise is large and covers a wide frequency band, for example, the volume and frequency characteristics of the received sound are adjusted in such a manner that only the middle frequency band, which is the frequency band of voice, is raised. (4) When the volume of noise is reduced or the sound field characteristic is changed, the volume of the received sound is reduced or the frequency characteristic is shifted accordingly. It becomes a mode like this.

Therefore, the received sound, which is converted into a sound by the transmitter / receiver, is properly protected from the noise around it, and can be reproduced as a sound that is truly easy for the user to hear.

Here, the handset may be a device for performing the above-mentioned hands-free call, a handset, or both of them.

Further, in the invention described in claim 2, when the handset is configured to have at least the device for performing the above-mentioned hand-free call, as a means for suppressing the echo generated there, The filter means is further provided.

Here, the filter means is, for example, an adaptive filter that uses adaptive signal processing such as a least square method or a projection algorithm as its algorithm. Therefore, in this case, if the control means automatically adjusts at least one of the volume and frequency characteristics of the received sound with reference to the suppressed residual echo, the echo generated in the hands-free call is also taken into consideration. Thus, it is possible to further optimize the received sound.

Further, particularly in this case, if the volume of the received sound and / or the frequency characteristic is automatically adjusted so that the level of the residual echo is minimized as in the invention according to the third aspect, It is also possible to accurately cancel the echo generated in the hands-free call.

Further, in the invention described in claim 4, when the handset is further configured to have a handset, the handset is switched to the handset side by the switch means. The reference for the residual echo is canceled.

That is, since the above-mentioned echo hardly occurs in the handset call, by canceling the reference of the residual echo in this way during the handset call,
Based on the noise information detected by the noise information sensor, the state in which the received sound is protected from those noises is maintained purely.

According to the invention of claim 5,
When the communication device is a mobile telephone device mounted on a mobile body, the noise information sensor is configured as one or more of a speed sensor, an acceleration sensor, and a noise sensor mounted on the mobile body. By doing so, it is not always necessary to provide a new sensor to detect the noise information. For example, when the telephone device is installed in an automobile, the noise level and the noise frequency in the vehicle interior of the vehicle can be estimated to some extent based on the vehicle speed information and the acceleration information detected by the vehicle speed sensor and the acceleration sensor. Become.

Further, in the invention according to claim 6, the control device is arranged such that "the signal level adjustment amount and the frequency by the sound volume adjusting means corresponding to various noise levels and various sound field frequency characteristics around the handset. A control pattern memory in which the adjustment amount of the frequency characteristic by the adjusting means is registered in advance as a control pattern ", and a corresponding control pattern is generated from the control pattern memory based on the noise information detected at each time by the noise information sensor. It is supposed to be read.

According to such a configuration of the control device, it is possible to more easily realize the analysis of the noise characteristic around the handset based on the noise information and the control of the volume adjusting means and the frequency adjusting means based on the analysis. become able to.

According to the seventh aspect of the invention, as a so-called echo canceller of a device for making a hands-free call, it is possible to further improve its echo canceling capability.

That is, as described above, there is an adaptive filter that uses adaptive signal processing such as a least square method or a projection algorithm as the filter means, but such filter means usually: At least one of the two signals is adjusted, and the received signal that is converted into a voice signal through the loudspeaker is used as a reference signal to suppress the echo component in the transmitted signal path that correlates with the received signal. Therefore, the suppression mode of the echo component is directly influenced by the signal level and frequency characteristic of the received signal serving as the reference signal.

Therefore, in the control means, while monitoring the output (that is, the residual echo) of the filter means, the signal level or frequency characteristic of the reception signal,
Alternatively, if both the adjustment modes are controlled, more precise control can be performed in suppressing the echo component.

Further, in this case, if the volume of the received sound and / or the frequency characteristic is automatically adjusted so that the level of the residual echo is minimized as in the invention according to claim 8, the hand is It also becomes possible to accurately cancel the echo generated in the free call.

Regarding the residual echo output from the filter means, for example, a residual echo smoothing means for taking the long-term average and smoothing the level is provided, and the smoothed output is given to the control means. You may do it. By providing such residual echo smoothing means, it becomes possible to more stably refer to the residual echo level.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a communication device according to the present invention. The device of this embodiment is assumed to be a communication device used in the interior of the automobile, such as an automobile telephone installed in the automobile or a mobile telephone installed and used in the interior of the automobile.

First, with reference to FIG. 1, the configuration of the apparatus of this embodiment and the function of each component will be described. In the apparatus of the embodiment, the radio unit 1 is a well-known unit that has an antenna, a transceiver, and the like, and exchanges various control signals and call signals with the base station. The transmission / reception protocol for exchanging these signals and other controls are centrally executed through the wireless control unit 2.

The voice CODEC 3 is a well-known part which mainly performs coding and decoding of a voice signal. And these processes in the CODEC3 are also
Overall control is performed through the wireless control unit 2.

The received sound adjusting section 4 connected to the audio CODEC 3 is a section for automatically adjusting the volume and frequency characteristics of the received signal a decoded through the audio CODEC 3.

Here, the volume adjusting section 41 which constitutes the receiving sound adjusting section 4 is a section which adjusts the volume of the receiving signal a, and the frequency characteristic adjusting section 42 which constitutes the receiving sound adjusting section 4 is The frequency characteristics of the volume-adjusted reception signal b,
That is, it is a part for adjusting the sound quality. The voice signal c whose volume and frequency characteristics have been adjusted by the volume adjusting section 41 and the frequency characteristic adjusting section 42 is transmitted by the handset switch 9
It is given to the handset 6 (more precisely, its speaker section) or the loudspeaker 7 via the, and is converted into electric-voice as a received sound there.

Further, the respective adjustment amounts by the volume adjusting unit 41 and the frequency characteristic adjusting unit 42 are output by various sensors 43 constituting the received sound adjusting unit 4 and the residual echo smoothing unit 44.
Based on the output of the control unit (CP
U) It is automatically controlled through 45.

Incidentally, in the case of the apparatus of this embodiment, as the various sensors 43, the vehicle speed sensor of the automobile, the acceleration sensor, or both of these sensors are used. That is, by monitoring the outputs of these vehicle speed sensors and acceleration sensors, it is possible to estimate the state of noise in the passenger compartment of the vehicle to some extent. Therefore, in the device of the embodiment, these vehicle speed sensors and acceleration sensors mounted in advance are used. The sensor is also actively used as a noise sensor.

As the mode of estimating the state of the noise in the vehicle compartment based on the outputs of the vehicle speed sensor and the acceleration sensor, for example, roughly, (a) the level of the noise is detected when the vehicle speed sensor detects a low vehicle speed. Is estimated to be relatively small, and its frequency characteristics are also offset to the low frequency side. (B) In a state where the vehicle speed sensor detects the medium vehicle speed, it is estimated that the noise level is slightly increased and the frequency characteristic is slightly shifted to the middle range. (C) When the vehicle speed sensor detects a high vehicle speed, it is estimated that the noise level is high and the frequency characteristic is shifted to a slightly higher range. (D) It is estimated that the noise level is temporarily increased during the period when the acceleration state is detected by the acceleration sensor and the frequency thereof is also temporarily shifted to the high frequency side. Etc. are possible. In reality, these estimation modes are in the form of more finely interpolated according to the value of the sensor output.

The residual echo smoothing section 44 is a section for smoothing the residual component (residual echo) of the echo suppressed by the adaptive signal processing section 5 described later by, for example, averaging for a long time. The smoothing output of the residual echo by the residual echo smoothing unit 44 is also referred to by the control unit 45 when controlling the adjustment amounts by the volume adjusting unit 41 and the frequency characteristic adjusting unit 42.

Further, the control pattern memory 46 constituting the received sound adjusting section 4 is a memory in which the control pattern of the adjustment amount of the volume and the frequency characteristic by the control section 45 is registered in advance. That is, in the case of the device of this embodiment, the memory 46 has the above-mentioned volume that can protect the received sound from the noise according to the state of the noise in the vehicle cabin estimated as described in (a) to (d) above. The control pattern of the adjustment amount of the frequency characteristics is registered, and the control unit 45 selects the control pattern suitable for the estimated noise state each time.

Incidentally, as such a control pattern,
This is also large (1) When the volume of noise is relatively low, the volume of the received sound is increased. (2) Even if the volume of noise is large, if the frequency band is limited to a certain range, the frequency characteristic of the received sound is shifted so that the frequency band is out of this specific range. At the same time, the volume of the received sound may be increased. (3) When the volume of noise is large and covers a wide frequency band, for example, the volume and frequency characteristics of the received sound are adjusted in such a manner that only the middle frequency band, which is the frequency band of voice, is raised. (4) When the volume of noise is reduced or the sound field characteristic is changed, the volume of the received sound is reduced or the frequency characteristic is shifted accordingly. A pattern such as "and so on" is possible. Also, this is actually registered as a form in which these patterns are interpolated more finely.

As for the smoothed output of the residual echo by the residual echo smoothing unit 44, for example, the volume adjustment amount, the frequency characteristic adjustment amount, or both of them are the same so that the output level becomes the minimum. It is controlled through the control unit 45. Regarding the smoothed output of the residual echo,
The control patterns for minimizing the output levels may be prepared in advance in the control pattern memory 46 in accordance with the output levels. The volume adjusting unit 41 and the frequency characteristic adjusting unit 4 according to the level of the smoothed output.
The control mode of 2 can be empirically determined through a preliminary experiment or the like.

On the other hand, in the apparatus of the embodiment, the adaptive signal processing section 5 electrically connected between the loudspeaker 7 and the hands-free microphone 8 which constitute the hands-free apparatus is exclusively hands-free as a so-called echo canceller. This is the part that suppresses the echo that occurs during a call.

As is well known, the echo is a phenomenon in which a part of the received sound which is converted into electric sound through the loudspeaker 7 is circulated to the hands-free microphone 8 and converted into sound. Particularly in a hands-free call in which the loudspeaker 7 and the hands-free microphone 8 are used, such an echo will be generated more or less. When this echo component is increased, a state close to what is called howling may be induced. Therefore, in the device of this embodiment, when the hands-free device is selected as the handset by the handset switch 9, the echo signal is suppressed by the adaptive signal processing section 5.

As shown in FIG. 1, the adaptive signal processing section 5 monitors the actual degree of suppression based on the correlation with the received signal c which is converted into the electric-speech, and at each time. An adaptive filter 51 for generating a signal corresponding to an echo component to be suppressed, and an adder (subtractor) 52 for subtracting the generated signal from the signal d which is voice-electrically converted by the hands-free microphone 8 are provided. It is configured to have.

FIG. 2 exemplifies the configuration of such an adaptive signal processing unit 5, including a specific example of the adaptive filter 51.
As shown in FIG. 2, the adaptive filter 51 inputs the received signal c as a signal x (k), and outputs the signal x (k) as x (k-1), ..., X (k). -N +
As 1), delay (z conversion) is performed step by step. .Coefficients h0 and h1 respectively corresponding to these delayed signals
, ..., HN-1 are multiplied, and the sum signal is output to the adder 52 as a signal corresponding to the echo component to be suppressed. It is configured as a circuit that repeatedly executes such processing.

In the adder 52, the output of the adaptive filter 51 is subtracted from the signal (speech signal) d voice-electrically converted by the hands-free microphone 8 to suppress the echo component. That is, when the electrically converted signal d is composed of only echo components, the addition (subtraction) output e becomes the rest of the echo components suppressed by the adaptive signal processing unit 5, that is, the residual echo.

This residual echo e is added to the above-mentioned residual echo smoothing section 44 to be smoothed, and the coefficients h0 and h1 thereof are adjusted in the adaptive filter 51.
, ..., hN-1 is fed back to the adaptive filter 51 as a monitor signal for changing.

In the adaptive filter 51 to which the residual echo e is fed back, the least squares method (NLMS (Normal
ized Least Mean Square) algorithm) and a projection algorithm such as adaptive algorithm.
The respective values of h1, ..., hN-1 are determined.

That is, in the adaptive filter 51,
When the current coefficient is hi (k) and its correction amount is Δhi (k) (where i is 0, 1, ..., N-1, and k is the number of times of control), hi (k + 1) = The next coefficient hi (k + 1) based on the feedback of the residual echo e is determined in the form of hi (k) + Δhi (k). For example, in the case of the least square method, the correction amount Δh
i (k) is Δhi (k) = η {x (k-i) / | X (k) | ^ 2}
e (k) Here, ^ indicates a power. Will be given as. Here, X (k) in the above equation is an echo component, and X (k) = {x (k), x (k−1), ..., X (k−N)
+1)}. Further, η is a learning coefficient, which is a constant value set in the range of 0 <η <2.

By performing such adaptive signal processing on the signal (echo) d through the adaptive signal processing section 5, the echo d is suppressed in the mode shown in FIG.

Incidentally, in FIG. 3A, in FIG. 3A, a part of the received sound, which has been converted into a sound through the loudspeaker 7, is circulated into the hands-free microphone 8 and the echo d is converted into a sound. The mode of occurrence is shown. Further, FIG. 3B shows a suppression mode of the echo d by the adaptive signal processing unit 5. Then, the echo after suppression shown in FIG. 3B, that is, the residual echo e is taken in by the residual echo smoothing unit 44 of the reception sound adjusting unit 4 on the one hand, and FIG.
In the mode shown in (c), the level comes to be smoothed. The smoothed residual echo f is given to the control unit 45 in the reception sound adjustment unit 4 and, for example, the volume adjustment unit 41 and the frequency characteristic adjustment unit 42 are provided through the control unit 45 so that the level becomes minimum. The adjustment mode is controlled as described above with reference to FIG.

FIG. 4 shows the processing procedure of the processing mainly executed by the control section 45 in the reception sound adjusting section 4. Next, referring to FIG. The overall operation of the example device is further detailed.

That is, now, an incoming call to the communication device,
Alternatively, if a call is initiated by the user by the call device (step S10 in FIG. 4), the control unit (CPU) 45, which has recognized the fact based on a command from the wireless control unit 2, firstly executes the above-mentioned operation. The sensor signals at that time are fetched by the various sensors 43 (step S1 in FIG. 4).
1). As described above, in the case of the apparatus of the embodiment, the sensor signal is vehicle speed information obtained by the vehicle speed sensor or acceleration information obtained by the acceleration sensor.

Then, the control unit 45 determines whether the user is currently in a call state by the hands-free function or the handset 6 based on the state of the handset switch 9 (FIG. 4). Step S1
2).

As a result, when it is judged that the call is in the call state by the hands-free function, the residual echo f smoothed by the residual echo smoothing unit 44 in the mode illustrated in FIG. 3C is used. Input (Step S1 in Figure 4)
3).

On the other hand, as a result of the determination, when it is determined that the handset 6 is in the communication state, the acquisition of the residual echo f is canceled. In the case of a handset call, the above-mentioned echo is hardly generated. Therefore, by canceling the acquisition of the residual echo f in this way, unnecessary information is referred to as the above-mentioned information for adjusting the volume and frequency characteristics of the received sound. You will be able to avoid that.

In this way, the control unit 45, which takes in the sensor signal and also takes in the smoothed residual echo f in the case of the call state by the hands-free function, estimates the state of noise in the vehicle compartment based on the sensor signal. Then, the control pattern suitable for the estimated noise state is determined (step S14 in FIG. 4). The control unit 45 estimates such a noise state. For example, (a) when the vehicle speed sensor detects a low vehicle speed, the noise level is relatively low, and the frequency characteristic is also biased to the low frequency side. Estimate. (B) In a state where the vehicle speed sensor detects the medium vehicle speed, it is estimated that the noise level is slightly increased and the frequency characteristic is slightly shifted to the middle range. (C) When the vehicle speed sensor detects a high vehicle speed, it is estimated that the noise level is high and the frequency characteristic is shifted to a slightly higher range. (D) It is estimated that the noise level is temporarily increased during the period when the acceleration state is detected by the acceleration sensor and the frequency thereof is also temporarily shifted to the high frequency side. What is done in such a mode as described above is as described above. Then, as a control pattern suitable for these estimated noise states, for example, (1) when the noise volume is relatively low, the volume of the received sound is increased. (2) Even if the volume of noise is large, if the frequency band is limited to a certain range, the frequency characteristic of the received sound is shifted so that the frequency band is out of this specific range. Alternatively, the volume of the received sound is also increased. (3) When the volume of noise is large and covers a wide frequency band, for example, the volume and frequency characteristics of the received sound are adjusted in such a manner that only the middle frequency band, which is the frequency band of voice, is raised. (4) When the volume of noise is reduced or the sound field characteristic is changed, the volume of the received sound is reduced or the frequency characteristic is shifted accordingly. It is also described above that patterns such as "etc." are prepared in advance in the control pattern memory 46. Therefore, in the control unit 45, for example, as described in (B) above, the noise level is somewhat high, and the frequency characteristic thereof is shifted to the midrange. If it is estimated, for example, as in (2) above, the frequency characteristic is shifted so that the frequency band of the received sound is out of this specific range. At the same time, increase the volume of the received sound. Will be determined as a control pattern suitable for the estimated noise state.

The control unit 4 having the control pattern thus determined
Reference numeral 5 reads the determined control pattern from the control pattern memory 46 (step S15), and sets the volume adjusting unit and the frequency characteristic adjusting amount based on the read control pattern so that the volume adjusting amount and the frequency characteristic adjusting amount are required amounts. Four
1 and the frequency characteristic adjusting unit 42 are controlled (steps S16 and S17 in FIG. 4).

Further, in the case where the smoothed residual echo f is also taken in (when hand-free communication is being performed), the control unit 45 adapts the above-mentioned adaptation according to the level of the smoothed residual echo f. The degree of echo suppression and the quality of received sound in the signal processing unit 5 are estimated. Normally, the smaller the level of the smoothed residual echo f, the more efficiently the echo is suppressed, and the higher the quality of the received sound with less echo is obtained. Therefore, in this case, in the control unit 45, for example, the smoothed residual echo f
The control amount for the sound volume adjusting unit 41 and the frequency characteristic adjusting unit 42 is finely adjusted in the direction in which the level is minimized.

In the apparatus of this embodiment, such processing through the control unit 45 is repeatedly executed until the above-mentioned started call is ended (step S18 in FIG. 4). Incidentally, it is assumed that these processing cycles by the control unit 45 are equal to or longer than the sampling cycle of the signal input to the communication device.

Therefore, according to the apparatus of the embodiment, the received sound, which is converted into the electric sound through the loudspeaker 7 or the handset 6, whether it is a call by the hands-free function or a normal call by the handset, is in the passenger compartment. Will be properly protected from the noise. Therefore, the received sound is reproduced as a voice that is truly easy for the user to hear.

In the apparatus of this embodiment, when a hands-free call is being performed, the volume and frequency characteristics of the received sound are adjusted so as to minimize the level of the smoothed output f of the residual echo. I made adjustments. However, as described above, also for the smoothed output f of the same residual echo, those control patterns for minimizing the smoothed output f may be prepared in the control pattern memory 46 in advance. . In this case, the control pattern prepared in the memory 46 may be in a form different from the control patterns exemplified as the above (1) to (4), or may be included in the control patterns in advance. It may be one.

In the same device, however, the use of such a control pattern is not essential. Besides, for example, sensor outputs from various sensors 43 and smoothed output f of the residual echo
It is also possible to adopt a configuration in which an appropriate function calculation based on is executed to determine the adjustment amount for the volume and frequency characteristics of the received sound at each time. Even with such a configuration, the same effect as the above can be obtained. However, in actual implementation as a device, the configuration including the control pattern memory 46 is easier and has excellent maintainability.

Although omitted in the description of the embodiment for the sake of convenience, the case where the user speaks to the hands-free microphone 8 and this voice-electric conversion is performed by the microphone 8 is called "double talk". In this case, the smoothing process by the residual echo smoothing unit 44 is performed not only on the residual echo component itself but also on the transmission signal by this user, and this is given to the control unit 45 as its output f. Will be done. Therefore, in such a case, the control unit 45 determines whether or not the “double talk” is present, for example, based on the level of the output f, and when it is determined to be the “double talk”, the output f is appropriately set Perform weighting. Such processing as described above is also performed. By performing such processing in combination, it is possible to preferably avoid the above-described influence of the transmission signal from the user on the detection of the residual echo level.

Further, in the apparatus of the embodiment, a vehicle speed sensor or an acceleration sensor mounted in advance is used as the various sensors 43, but a noise sensor for directly detecting the state of noise inside and outside the vehicle is used. When the noise sensor can be separately provided, the noise sensor may be used as the various sensors 43. Further, according to the apparatus of the embodiment, by arranging the above-mentioned reception sound adjusting section 4, the reception sound can be optimized not only in the hands-free communication but also in the communication using the handset 6. You can do it. Therefore, in the same embodiment, a normal call using the handset and a voice call using the hands-free function can be arbitrarily selected, but in practice, it is assumed that only one of these handsets is provided. The communication device can be configured. In any of these cases, it is possible to provide the user with a sound field in which the received sound is really easy to hear.

Further, in the case of the apparatus of the same embodiment, particularly in the case of a voice call using the hands-free function, the reception sound adjusting section 4 and the adaptive signal processing section 5 described above cooperate with each other. The echo canceller is also configured to realize extremely fine echo cancellation.

That is, as described above, the adaptive signal processing unit 5 uses the reception signal, which is converted into the electric sound through the loudspeaker 7, as the reference signal, and suppresses the echo component in the transmission signal path correlated with the reception signal. . Therefore, the suppression mode of the echo component is directly influenced by the signal level and frequency characteristic of the received signal serving as the reference signal.

Therefore, the control section 45 monitors the output (that is, the residual echo) of the adaptive signal processing section 5 and controls the adjustment level of the signal level of the received signal, the frequency characteristic, or both. With this, more precise control can be performed in suppressing the same echo component.

In this case, in particular, if these adjustment modes are controlled so that the level of the residual echo is minimized, it is possible to accurately cancel the echo generated in the hands-free call.

When used as such an echo canceller, the sensor outputs of the various sensors 43 in the received sound adjusting section 4 are not necessarily required. In the apparatus of the embodiment, the residual echo smoothing unit 44 is provided and the residual echo is smoothed and taken into the control unit 45. However, the control unit 45 itself accurately grasps the level of the residual echo. If it is possible, the smoothing part 44 does not need to be provided. That is, in this case, the communication device can be configured as a more compact device.

When the apparatus of this embodiment shown in FIG. 1 is realized as a mobile phone, various sensors 43 of the reception sound adjusting section 4 and a control section 45 surrounded by a broken line in FIG. The control pattern memory 46 and the control pattern memory 46 can be installed in the vehicle in advance as a device on the vehicle side. That is, in this case, the mobile phone has a configuration in which the above-mentioned respective parts are omitted, and when the same phone is installed in a vehicle, the respective parts and the same phone are electrically connected via an appropriate connecting means. With such a configuration, the portability of the mobile phone can be further enhanced.

Further, in the apparatus of the above embodiment, the volume adjusting section 41 may be, for example, various well-known programmable
For example, various well-known programmable equalizers can be used as the frequency characteristic adjusting unit 42.

Further, in the embodiment, a telephone device used in the interior of the automobile, such as an automobile telephone mounted in the automobile or a mobile telephone installed and used in the interior of the automobile, is assumed. It goes without saying that the communication device according to the present invention is not limited to the communication device used in the interior of such an automobile. In addition, for example, the present invention is applied to a telephone mounted on a moving body such as a train, an aircraft, or a ship, or a telephone installed in a relatively noisy environment such as a factory in a mode according to the above-described embodiment. Therefore, it is possible to provide the user with a sound field in which the received sound can be heard easily in any environment.

[0080]

As described above, according to the present invention, regardless of the handset call or the hands-free call, the state of the receiving sound is always automatically adjusted and maintained in an appropriate state with respect to the surrounding environment. Thus, it is possible to provide the user with a sound field that is truly easy to hear.

Further, according to the present invention, it is possible to further optimize the received sound, particularly considering the echo generated in the hands-free call. Further, according to the present invention, even as an echo canceller in the same hands-free call, it is possible to further improve the echo canceling capability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an embodiment of a telephone device according to the present invention.

FIG. 2 is a block diagram showing a configuration example of the adaptive filter shown in FIG.

FIG. 3 is a time chart schematically showing an echo processing mode by the communication device of the embodiment.

FIG. 4 is a flowchart showing a processing procedure of a received signal by the communication device of the embodiment.

[Explanation of symbols]

1 ... Wireless unit, 2 ... Wireless control unit, 3 ... Voice CODEC, 4
... earpiece sound adjustment section, 5 ... adaptive signal processing section, 6 ... handset, 7 ... loudspeaker, 8 ... hand-free microphone, 9 ... handset switch, 41 ... volume adjustment section,
42 ... Frequency characteristic adjusting unit, 43 ... Various sensors, 44 ... Residual echo smoothing unit, 45 ... Control unit (CPU), 46 ... Control pattern memory, 51 ... Adaptive filter, 52 ... Adder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshige Asada 1-1, Showa-cho, Kariya city, Aichi Prefecture NIDEC CORPORATION

Claims (8)

[Claims] 1. A handset for transmitting and receiving a call, wherein a voice signal which is voice-electrically converted by the handset is transferred to a partner as a transmitter signal, and a voice signal transferred from the partner is a receiver signal. In the communication device for converting the electricity into voice by the same transmitter / receiver, the volume adjusting means arranged in the transmission line of the reception signal to adjust the signal level of the reception signal, and the transmission line of the reception signal also A frequency characteristic adjusting means that is arranged to adjust the frequency characteristic of the reception signal, a noise information sensor that detects noise information consisting of the noise around the handset or a parameter corresponding to the noise, and a noise information sensor that detects the noise information. Based on the above, the amount of signal level adjustment by the volume adjusting means and the frequency adjusting means are performed so that the voice converted into electric sound by the handset is protected from this noise. A communication device comprising: a control unit that controls at least one of the adjustment amounts of the frequency characteristics by the. 2. A hand-free microphone for performing voice-electric conversion to generate the transmission signal, and a loudspeaker for performing electric-voice conversion of a reception signal in which at least one of the signal level and the frequency characteristic is adjusted. And a speaker device, wherein the communication device is arranged between the loudspeaker and the hands-free microphone, and the speech signal is electrically converted by the hands-free microphone. The control means further comprises filter means for suppressing the echo component of the sound converted by the loudspeaker, and the control means also refers to the suppressed residual echo, and adjusts the signal level by the volume adjusting means and the frequency. The communication device according to claim 1, wherein at least one of the adjustment amounts of the frequency characteristics by the adjusting means is controlled. . 3. The control means controls at least one of a signal level adjustment amount by the volume adjusting means and a frequency characteristic adjustment amount by the frequency adjusting means so that the level of the residual echo is minimized. The call device according to claim 2. 4. The transmission / reception device transmits a reception signal between the volume adjusting means and the frequency characteristic adjusting means and the filter means, and a transmission signal between the filter means and the control means. The transmission line is further configured to have a handset in which the electric-voice conversion means and the voice-electricity conversion means are respectively connected via the switch means, and the control means includes the handset on the handset side by the switch means. 3. The communication device according to claim 2, wherein the reference of the residual echo is released when being switched. 5. The communication device according to claim 1, wherein the communication device is a mobile phone device mounted on a mobile body, and the noise information sensor is mounted on the mobile body. And a speed sensor, an acceleration sensor, and a noise sensor. 6. The controller controls the signal level adjustment amount by the volume adjusting means and the frequency characteristic adjustment amount by the frequency adjusting means corresponding to various noise levels and various sound field frequency characteristics around the handset. 6. A control pattern memory pre-registered as a control pattern is provided, and a corresponding control pattern is read out from the control pattern memory based on noise information detected by the noise information sensor each time. The calling device according to any one of claims. 7. A hand-free device in which a hand-free microphone and a loudspeaker are separately arranged, and transfers a voice signal which is voice-electrically converted by the hand-free microphone as a transmission signal to a partner. In a speech communication device which takes in a voice signal transferred from the other party as a reception signal and converts the voice signal into a voice by a loudspeaker, a volume adjusting means arranged in a transmission path of the reception signal to adjust a signal level of the reception signal. And a frequency characteristic adjusting unit that is also arranged in the transmission path of the reception signal and adjusts the frequency characteristic of the reception signal, and is arranged between the loudspeaker and the hands-free microphone, and is electrically connected by the hands-free microphone. Suppresses the echo component of the voice converted by the loudspeaker from the converted transmission signal And a control means for controlling at least one of the amount of signal level adjustment by the volume adjusting means and the amount of frequency characteristic adjustment by the frequency adjusting means with reference to the suppressed residual echo. A communication device characterized by. 8. The control means controls at least one of an adjustment amount of a signal level by the volume adjusting means and an adjustment amount of a frequency characteristic by the frequency adjusting means so that the level of the residual echo is minimized. The communication device according to claim 7.