JP3154914B2 - Communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for controlling activation of a transmission device, and more particularly, to a communication device for activating a transmission device when a voice signal is included in an input signal.

[0002]

2. Description of the Related Art Conventionally, as a communication device of this type, it is conventionally determined whether or not the average voltage of an input signal exceeds a predetermined voltage value, and when it is determined that the average voltage exceeds a predetermined voltage value, a transmission device is activated. There is known a device provided with a signal level discriminating unit for outputting a press signal for causing the signal to be transmitted to a transmitting device. In this conventional communication device, the signal level discrimination unit amplifies an input signal and then rectifies the signal, and the average voltage value of the rectified signal exceeds, for example, the average voltage value of noise generally considered to be input. It is determined whether or not the voice signal has been exceeded, and when it is determined that the voice signal has been exceeded, it is assumed that a voice signal has been input, and a press signal is output to the transmitting device. Thereby, the transmission device is activated, and the input signal amplified by the signal level determination unit is transmitted by the transmission device.

[0003]

However, the conventional communication apparatus has a problem that noise is erroneously detected as a voice signal because only the voltage value of the input signal is to be determined. This problem is particularly noticeable in a transmission / reception system that uses a plurality of simplex-type portable wireless devices that use the same frequency as a transmission / reception frequency and performs hands-free transmission / reception for a construction site or for mounting on a motorcycle. Become. That is, when a plurality of portable wireless devices each including a receiving device and a transmitting device equipped with a signal level discriminator are used, and a sound is input to a microphone connected to each transmitting device, the transmitting device is automatically activated. If the signal level determination unit of one portable radio device erroneously detects construction noise or wind noise as an audio signal when performing hand-free intercommunication by activating the portable radio device, the portable radio device Is activated, and the noise or the like is immediately transmitted. As a result, even if an emergency notification message is transmitted from another portable wireless device, the portable wireless device in which the transmitting device is activated,
The emergency message cannot be received because the receiving device has not been activated. Another problem is that if noise or the like is transmitted, other portable wireless devices will output harsh sounds.

[0004] The present invention has been made in view of such a problem, and has as its object to provide a communication device that can activate a transmission device only when an input signal includes a voice signal. .

[0005]

In order to achieve the above object,
A communication device according to claim 1, wherein the transmission device transmits an input signal input to the signal input means, a control unit that activates the transmission device when the input signal includes a voice signal ,
And a simplex communication device.
Receiving and outputting an incoming signal indicating reception of the received signal
A communication device comprising: a register unit for storing digital audio data obtained by performing an analog-to-digital conversion of an input signal; and a plurality of linear prediction analysis processes performed by performing a linear prediction analysis process based on the digital audio data stored in the register unit. A linear predictor for calculating the prediction error, a correlator for calculating the autocorrelation of the obtained plurality of prediction errors, a fundamental frequency extractor for extracting the fundamental frequency of the input signal based on the calculated autocorrelation, and vocal cord vibration A memory that stores the upper limit value to the lower limit value of the basic frequency band of the voiced sound as a pitch frequency band, and determines whether the extracted basic frequency is a pitch frequency within the pitch frequency band stored by the memory. A pitch frequency discriminator, and the controller determines that the extracted fundamental frequency is a pitch frequency by the pitch frequency discriminator. Occasionally, to activate the transmitter device, linear
Predictor, the correlator, fundamental frequency extractor you and pitch frequency
The discriminator changes from the state with the incoming signal to the state without the incoming signal.
Characterized that you have been configured to start each time the.

A communication device according to a second aspect of the present invention is the communication device according to the first aspect, further comprising a signal level determination unit that determines whether the signal level of the input signal is equal to or higher than a predetermined level, and further comprising a linear predictor. , The correlator, the fundamental frequency extractor, and the pitch frequency discriminating unit are configured to be activated when the input signal is judged to have a predetermined level or higher by the signal level discriminating unit.

According to a third aspect of the present invention, there is provided the communication apparatus according to the first or second aspect, further comprising delay means for delaying an input signal input to the signal input means and outputting the delayed signal to the transmission apparatus. Is set to be equal to or longer than the time difference between the time when the first input signal of the input signals is input to the signal input means and the time when the control unit activates the transmission device.

According to a fourth aspect of the present invention, there is provided a communication apparatus according to the first aspect.
3. The communication device according to claim 3 , wherein:
The correlator, the fundamental frequency extractor, and the pitch frequency discriminator are characterized by being constituted by a digital signal processor.

[0009]

In the communication device according to the first aspect, when an input signal is input to the signal input means, the register unit stores digital voice data obtained by converting the input signal from analog to digital. Next, based on the digital audio data stored in the register unit, the linear predictor performs a linear prediction analysis process to obtain a plurality of prediction errors, and the correlator calculates the autocorrelation of the obtained plurality of prediction errors. . Next, a fundamental frequency extractor extracts a fundamental frequency of the input signal based on the autocorrelation. Then, the pitch frequency determination unit determines whether the extracted fundamental frequency is a pitch frequency within the pitch frequency stored in the memory, that is, whether the input signal includes a sound accompanied by vibration of a human vocal cord. Is determined. In this case, when it is determined that the fundamental frequency of the input signal is the pitch frequency, the control unit activates the connected transmitting device. Thus, the input signal is transmitted by the transmitting device. As described above, the transmitting device is activated when the input signal includes a sound accompanied by vocal cord vibration. Therefore, even if noise such as noise or wind noise is input to the signal input unit, the transmitting device is erroneously determined to be a voice, and , And the transmitting device is reliably started only when an audio signal is input.

Further , in this communication device, the receiving device
The incoming signal is received once the incoming signal is received.
When this happens, a linear predictor, correlator,
The fundamental frequency extractor and pitch frequency discriminator start.
You. In other words, when communicating by simplex communication
And when the other party's transmission ends, a linear prediction
Detector, correlator, fundamental frequency extractor and pitch frequency discrimination
The unit is started immediately and the input signal input to the signal input means
Extraction processing of the fundamental frequency and the fundamental frequency
It is in a state of waiting for the execution of the process of determining whether the
You. Therefore, communication simplex communication
If the signal is sent to the user, the signal level
The linear predictor, correlator, and fundamental frequency
Since the output unit and the pitch frequency discriminating unit start immediately,
The time until the transmitting device starts up is shortened, and the delay means
Prevents truncation of transmitted audio during transmission without using
be able to. Also, when delay means are used,
In addition, the delay time of the delay means can be reduced.
Therefore, the delay means can be reduced in size accordingly.

In the communication device according to the second aspect, when a signal is input, the signal level determining unit determines that the signal level of the input signal is higher than, for example, the average voltage of noise generally considered to be input. It is determined whether the value is equal to or higher than a predetermined level which is a value. Then, when the input level is determined by the signal level determination unit to be equal to or higher than the predetermined level, the linear predictor, the correlator, the fundamental frequency extractor, and the pitch frequency determination unit are activated and perform predetermined operations. Thereafter, when the fundamental frequency extracted by the linear predictor, the correlator, and the fundamental frequency extractor is determined as the pitch frequency by the pitch frequency determining unit, the control unit activates the transmitting device. As described above, the communication device activates the transmission device only when the signal level of the input signal is equal to or higher than the predetermined level and when the input signal includes a sound accompanied by vocal fold vibration. Surely, the transmission device can be activated only when an audio signal is input. Moreover, the linear predictor, correlator, fundamental frequency extractor, and pitch frequency discriminator are activated only when the input signal is discriminated by the signal level discriminator to be equal to or higher than the predetermined level, so that the current consumption is reduced accordingly. Thus, the power consumption of the communication device can be reduced.

In the communication device according to the third aspect, the delay unit delays the input signal input to the signal input unit and outputs the input signal to the transmission device. In this case, the delay means starts from the time when the first input signal of the input signals is input to the signal input means.
The input signal is delayed by a delay time that is equal to or longer than the time difference until the control unit starts the transmission device. For this reason, even if it takes some time for the processing in the linear predictor, correlator, fundamental frequency extractor and pitch frequency discriminating unit, it is input to the transmitting device with a delay of that much time or more. The beginning of the transmitted voice is prevented from being cut off.

In the communication device according to the fourth aspect, the linear predictor, the correlator, the fundamental frequency extractor, and the pitch frequency discriminator are constituted by a digital signal processor. In this case, the digital signal processor is suitable for the process of extracting the fundamental frequency of the input signal and the process of determining whether or not the extracted fundamental frequency is the pitch frequency, and can be highly integrated. The communication device can be downsized. In addition, when a signal level discriminator is provided, the digital signal processor is activated only when the signal level discriminator determines that the signal level of the input signal is equal to or higher than a predetermined level. For this reason, even if the power consumption during operation of the digital signal processor is large, no current is consumed when no input signal is input to the signal input means, so that the current consumption of the communication device is reduced accordingly. be able to.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication device according to one embodiment of the present invention will be described below in detail with reference to the drawings. First, a first embodiment will be described. FIG. 1 shows a communication device 1. The communication device 1 includes a transmission / reception unit 2, an antenna 3, a voice input unit (signal input means) 4, an automatic / manual mode switch 5, a priority mode switch 6, a press switch 7, A
/ D converter 8, voice discriminator 9, controller 10, display 1
1, delay circuit (delay means) 12, level discriminating section (signal level discriminating section) 13, low frequency amplifying section 14, and speaker 1
5 is provided.

The transmitting / receiving unit 2 includes a transmitting unit (transmitting device) 21,
A receiving unit 22 and an antenna switch 23 are provided.
Although not particularly limited, the transmitting unit 21 is configured to be able to transmit the 430 MHz band FM wave at 10 mW. In addition, the receiving unit (receiving device) 22 can receive the FM wave having the same frequency as the transmission frequency, and when receiving the received signal, transmits the squelch signal as the incoming signal to the control unit 10.
Is configured to be output. Note that an RSSI signal obtained by detecting an intermediate frequency may be used instead of the squelch signal. In the transmitting / receiving section 2, under the control of the control section 10,
When one of the transmission unit 21 and the reception unit 22 operates, communication by a so-called simplex method can be performed. The antenna switch 23 connects one of the transmission unit 21 and the reception unit 22 to the antenna 3, and the switching of the connection is controlled by the control unit 10.

The voice input unit 4 includes a microphone 25 and a microphone amplifier 26. Microphone 2
Reference numeral 5 denotes a so-called bone conduction microphone, which is embedded in a headphone (not shown), picks up vibration transmitted through a human skull when uttering voice, converts the vibration into a voice signal, and converts the converted voice signal into a microphone amplifier. 26. The microphone amplifier 26
The input audio signal is amplified to a predetermined level, and the amplified audio signal is output to the A / D conversion unit 8, the delay circuit 12, and the level determination unit 13 as a microphone signal.

Automatic / manual mode changeover switch 5
Switches the communication device 1 to one of the automatic mode and the manual mode. When the automatic / manual mode switch 5 is turned on, the communication device 1 is set to the automatic mode. In this automatic mode, when the microphone signal output from the audio input unit 4 includes an audio component, the control unit 10. The transmission unit 21 is activated by 10. On the other hand, when the automatic / manual mode switch 5 is turned off, the communication device 1 is set to the manual mode. In the manual mode, the control unit 10 controls the transmission unit 21 only when a press signal is output from the press switch 7. Is started.

The priority mode changeover switch 6 is connected to the communication device 1
Is switched to one of the transmission priority mode and the reception priority mode. When the priority mode switch 6 is turned on, the communication device 1 is set to the transmission priority mode. In this transmission priority mode, when the microphone signal includes an audio signal, the control unit 10 controls the receiving unit 22 even if the receiving unit 22 is in the operating state.
Is stopped, and the transmission unit 21 is activated with priority.
On the other hand, when the automatic / manual mode switch 5 is turned off, the communication device 1 is set to the reception priority mode. In this reception priority mode, as long as the squelch signal is output from the reception unit 22, the control unit 10 controls the transmission unit 21 even when the microphone signal includes an audio signal.
Is stopped, and the operation state of the receiving unit 22 is maintained.

The A / D conversion section 8 includes the microphone amplifier 2
The analog microphone signal output from 6 is converted into digital data, and the converted digital audio data is output to the audio discriminating unit 9.

The audio discriminating section 9 is provided with a digital signal
Processor (Digital Signal Processor)
P "), and determines whether or not the digital audio data output from the A / D converter 8 includes an audio component (audio signal). An audio detection signal for activating the unit 21 is output to the control unit 10. The voice discriminating unit 9 includes a register unit 31,
Linear predictor 32, correlator 33, fundamental frequency extractor 34,
A pitch frequency determination unit 35 and a clock generation unit 36 are provided. Note that the linear predictor 32, the correlator 33, and the fundamental frequency extractor 34 constitute a fundamental frequency extracting unit.

The register section 31 includes a sampling circuit for sampling digital audio data at predetermined time intervals;
A register for storing the sampled digital audio data. The linear predictor 32 obtains a plurality of prediction errors εt by performing a linear prediction analysis process based on the digital audio data stored in the register unit 31 as described later. The correlator 33 calculates the autocorrelation of the obtained plural prediction errors εt. Fundamental frequency extractor 34
Extracts a fundamental frequency based on the autocorrelation calculated by the correlator 33.

The pitch frequency discriminating section 35 has a memory (pitch frequency band storage section) 35a therein, and the memory 35a stores a fundamental frequency band of voiced sound accompanied by vocal cord vibration when a human produces a sound. The pitch frequency data corresponding to the upper limit value and the lower limit value of the frequency band (60 Hz to 300 Hz) are stored as pitch frequency band data. When the pitch frequency discrimination unit 35 determines that the fundamental frequency extracted by the fundamental frequency extractor 34 is a frequency within the lower limit value from the upper limit value of the pitch frequency band data, the speech component is included in the digital speech data. And outputs a voice detection signal to the control unit 10.

The clock generation unit 36 includes the linear predictor 32,
A clock signal for operating the correlator 33, the fundamental frequency extractor 34, and the pitch frequency discriminator 35 is generated. The clock generation unit 36 is activated when the sleep mode release signal is output from the control unit 10, and supplies a clock signal to each unit. On the other hand, when the sleep mode release signal is not output, the clock generation unit 36 is in the operation stop state, and the supply of the clock signal to each unit is stopped, so that the sound determination unit 9 is set to the sleep mode. You. In the sleep mode, the linear predictor 32, the correlator 33, the fundamental frequency extractor 34, and the pitch frequency discriminator 35 are put into an operation stop state, and as a result, the current consumption of the voice discriminator 9 is reduced.

Next, the operation of the voice discriminating section 9 will be described. The linear predictor 32 calculates the prediction error εt after approximating the current audio signal with the amplitude of the audio signal based on the digital audio data sampled in the past based on the digital audio data stored in the register unit 31. .

More specifically, since an audio signal generally has a high correlation between successive audio signals (sample values), the amplitude values Xi (i = 1) of some past audio signals are considered.
To p), a linear prediction coefficient ai (i = 1 to p)
And the sum Xp of all the values ap · Xi after the multiplication (shown in the following equation 1) can approximate the current amplitude Xt of the audio signal. For this reason, in the present embodiment, the linear predictor 32 calculates the amplitude Xt of the current audio signal.
As a plurality of audio signals sampled immediately before,
For example, the amplitudes (X (t-1) to X (t-1) to X
(T-12)).

[0026]

(Equation 1)

Next, the linear predictor 32 executes a linear prediction analysis process. In this linear prediction analysis process, the linear predictor 32 sets the linear prediction coefficients a1 to a4 to minimize the square value (εt) ² of the prediction error εt expressed by the following equation ( ² ).
The value of ap is obtained, and the prediction error εt at that time is calculated. In this case, the linear prediction coefficient ai
In calculating the prediction error εt, Levinson
An algorithm based on Durbin's recursive solution is used. The algorithm is stored in a program memory (not shown), and the linear predictor 32 performs a linear prediction analysis process according to the program.

[0028]

(Equation 2)

Next, the correlator 33 performs an autocorrelation process. In this autocorrelation processing, the correlator 33 calculates the prediction error εt obtained immediately before and the 128 prediction errors ε (t−1),.
27) is calculated as a function of the shift time τ. Next, the fundamental frequency extractor 34 finds the fundamental frequency from the reciprocal of the period of the remarkably shifted time τ. In this case, the fundamental frequency generally corresponds to the frequency of a sound accompanied by vibration of a human vocal cord (for example, a part of a consonant, a vowel and a semi-vowel).

The pitch frequency discriminating section 35 discriminates whether or not the fundamental frequency obtained by the fundamental frequency extractor 34 is a frequency within the pitch frequency band stored in the memory 35a.
When the pitch frequency discrimination unit 35 discriminates the fundamental frequency from the upper limit value to the lower limit value of the pitch frequency band data, the microphone signal output from the voice input unit 4 includes the voice component. The control unit 10
To output a voice detection signal.

The control unit 10 includes a one-chip microcomputer, and performs control operations such as transmission / reception switching processing and display processing.

Specifically, in the transmission / reception switching process, the control unit 10 controls the on / off state of the automatic / manual mode switch 5 and the priority mode switch 6 and the reception unit 2
Based on the presence / absence of the squelch signal output from 2 and the presence / absence of the voice detection signal output from the pitch frequency discrimination unit 35, one of the transmission unit 21 and the reception unit 22 is activated. More specific operation will be described later. In the display process, the control unit 10 controls the on / off state of the priority mode changeover switch 5, the transmission unit 21 and the reception unit 22.
By outputting to the display unit 9 display data relating to the operation state of, the ON / OFF state of the press switch 7, and the selection state of a frequency channel switch (not shown), these are displayed on the display unit 9.

The delay circuit 12 is constituted by a delay line composed of a coil, a capacitor, and the like, and delays a microphone signal and outputs the signal to the transmission unit 21. Specifically, the delay circuit 12
Is the microphone 25 of the first input signal of the input signals.
The microphone signal is delayed by a time equal to or longer than the time difference from the time when the input is input to the control unit 10 to the time when the transmission unit 21 is activated by the control unit 10. Thus, the delay circuit 12 prevents the transmission voice from being cut off at the time of transmission.

As shown in FIG. 2, the level determining section 13
An amplifier 41, a rectifier 42, and a comparator 43 are provided. The amplifier 41 amplifies the microphone signal output from the microphone amplifier 26 with a predetermined gain. Rectifier 4
Reference numeral 2 denotes a detection diode, which rectifies the microphone signal amplified by the amplifier 41. Comparison section 43
Is the voltage value (signal level) of the rectified microphone signal rectified by the rectifier 42, the resistance 44, the variable resistor 4
5 and a reference voltage value (predetermined level) set by the resistor 46. When the voltage value of the rectified microphone signal is larger than the reference voltage value, a level determination signal is output to the control unit 10. In this case, the comparing unit 43 shapes the waveform of the level determination signal using the Schmitt trigger IC provided therein.

The reference voltage value is, for example, a voltage value slightly larger than the average value of the noise signal that would be generally included in the microphone signal output from the audio input unit 4, and Is set by As a result. When the voltage value of the microphone signal exceeds the reference voltage value, the level determination section 13 determines that the microphone signal is an audio signal and outputs a level determination signal.

The low frequency amplifier 14 amplifies the received signal output from the receiver 22 with a predetermined gain, and outputs the amplified received signal to the speaker 15. The speaker 15 is built in the headphones described above, and outputs an input reception signal as a reception sound.

Next, the operation of the communication device 1 will be described.

First, the control unit 10 controls the automatic / manual mode switch 5 and the priority mode switch 6
Monitor the setting status of. As a result, when the automatic / manual mode changeover switch 5 is on and the priority mode changeover switch 6 is on, it is assumed that the automatic mode and the transmission priority mode are set.
The following transmission / reception switching processing is executed. In this mode, when a microphone signal is output from the audio input unit 4, the level determination unit 13 determines whether or not the voltage value of the microphone signal exceeds the reference voltage value. A level determination signal is output to the control unit 10. In parallel with this, the register section 31 samples the digital audio data input via the A / D conversion section 8 and stores it in the register.

When the control section 10 detects the input of the level discrimination signal, it outputs a sleep mode release signal to the speech discrimination section 9 so that the clock generation section 3 of the speech discrimination section 9 is output.
By activating 6, the linear predictor 32, correlator 33, fundamental frequency extractor 34, and pitch frequency discriminator 35 are operated. The voice discrimination unit 9 performs a linear prediction analysis process and a correlation process based on the digital voice data stored in the register unit 31. As a result, when it is determined that the voice component is included in the digital voice data, a voice detection signal is output to the control unit 10. Control unit 1
When the voice detection signal is input, the transmission control signal is output to the transmission unit 21 to activate the transmission unit 21. At about the same time, the microphone signal is output from the delay circuit 12 to the transmission unit 21, and the FM wave modulated by the microphone signal is transmitted from the antenna 3.

Note that once the voice detection signal is output, the control unit 10 continues to output the transmission control signal for a predetermined time even when the voice detection signal is interrupted, so that when the sound is intermittently sounded. This prevents the transmission / reception switching from being complicated. In addition, when the voice detection signal is not output from the pitch frequency determination unit 35, the control unit 10 continuously outputs the reception control signal to the reception unit 22, thereby maintaining the operation state of the reception unit 22. In this case, when receiving the reception frequency, the reception unit 22 outputs a squelch signal to the control unit 10.

Next, when the automatic / manual mode changeover switch 5 is turned on and the priority mode changeover switch 6 is turned off, control is performed assuming that the automatic mode and the reception priority mode are set. The unit 10 executes the following transmission / reception switching processing. The control unit 10 includes the receiving unit 2
When the squelch signal is output from the receiver 2, even if the voice detection signal is output from the pitch frequency discriminator 35, it is determined that the receiver 22 is receiving, and the reception control signal is continuously output. Is maintained in the receiving state. When the squelch signal is not output and the voice detection signal is output from the pitch frequency determination unit 35,
The control unit 10 stops the operation of the reception unit 22 by stopping the output of the reception control signal, and the transmission unit 21
The transmission unit 21 is activated by outputting a transmission control signal to the transmission unit 21.

Next, when the priority mode changeover switch 6 is turned off, the control section 10 outputs a press signal from the press switch 7 without monitoring the on / off state of the priority mode changeover switch 6. Only when the switch is ON, the transmission control signal is output to the transmission unit 21, and when the press signal is not output from the press switch 7, the reception control signal is output to the reception unit 22.

As described above, according to the first embodiment, the level discriminating unit 13 determines that the voltage value obtained by rectifying the microphone signal output from the audio input unit 4 exceeds the reference voltage value, and The transmitting unit 21 is activated only when the voice determining unit 9 determines that the digital voice data includes a voice component. Therefore, when noise such as noise or wind noise is input to the microphone 25, the voice discriminating unit 9 does not output a voice detection signal.
The transmitting unit 2 is not activated by mistake. On the other hand, when a voice is input to the microphone 25, the control unit 10
The transmission unit 21 can be started reliably.

Since the linear predictor 32, correlator 33, fundamental frequency extractor 34, pitch frequency discriminator 35, and clock generator 36 of the voice discriminator 9 are not operating at all times, current consumption can be reduced. As a result, the communication device 1
When the battery is driven by a small battery, the communication device 1 can be downsized because a small battery is sufficient, and when the same battery as the conventional communication device is used, the communication device 1 can be continuously used for a long time. can do.

The time required for the delay circuit 12 to perform the linear prediction process and the autocorrelation process by the voice discrimination unit 9 is equal to or longer than
Since the microphone signal is delayed and output to the transmission unit 21, it is possible to effectively prevent the transmission sound from being cut off.

In the first embodiment, an example has been described in which the control unit 10 outputs a sleep mode release signal when a level determination signal is output from the level determination unit 13 to the control unit 10. Is not limited to this. For example, when the state of the squelch signal (or RSSI signal) as an incoming signal from the receiving unit 22 changes to a state of no signal, that is, when the transmission of the other party is completed by the simplex communication, The clock generator 36 may be immediately activated by the controller 10 outputting the sleep mode release signal without monitoring the input of the level discrimination signal. In this case, the time required for the determination process of the level determination unit 13 can be made unnecessary.

As a result, it is possible to shorten the time until the transmission unit 21 is activated, and it is possible to prevent the transmission voice from being cut off at the time of transmission without using the delay circuit 12. Further, even if the delay circuit 12 is provided, the delay time can be reduced, so that the communication device 1 can be downsized accordingly. Note that, in this case, when the voice detection signal is not output from the pitch frequency determination unit 35 within a predetermined time from when the control unit 10 outputs the sleep mode release signal, the control unit 10 determines that the voice signal is not transmitted to the communication partner. It is preferable that the operation of the clock generation unit 36 be stopped by the device 10 stopping the output of the sleep mode release signal. In this case, the current consumption can be reduced accordingly. Further, in this case, when the level determination signal is output from the level determination unit 13, it is more preferable that the control unit 10 outputs the sleep mode release signal again.

Next, a second embodiment, which is a modification of the first embodiment, will be described with reference to FIG.

The second embodiment differs from the first embodiment in that an A / D converter 51 and a memory 52 are used instead of the delay circuit 12.
And the D / A converter 53 is used. In addition,
A / D converter 51, memory 52, and D / A converter 53
May be constituted by a one-chip microcomputer constituting the control unit 10. Also, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The A / D converter 51 converts the microphone signal output from the audio input unit 4 into digital digital audio data, and outputs the converted digital audio data to the memory 52. The memory 52 has a FIFO (First
In, First Out) memory, which is configured to be stored in the order of input and to be readable in the order of input. The memory 52 stores the digital audio data output from the A / D converter 51 from when the microphone signal is output from the audio input unit 4 to when the control unit 10 activates the transmission unit 21. It needs enough capacity to do that. Further, the D / A converter 53 converts the digital audio data read by the controller 10 into an analog audio signal.

When the voice detection signal is output from the pitch frequency discriminating unit 35, the control unit 10 reads out the digital voice data stored in the memory 52 and outputs it to the D / A conversion unit 53. The D / A conversion unit 53 converts the digital audio data into an analog audio signal, and outputs the converted audio signal to the transmission unit 21. By the above processing, the microphone signal is delayed by a time equal to or more than the time difference from when the first input signal of the input signals is input to the microphone 25 to when the control unit 10 activates the transmission unit 21. As a result, the beginning of the transmitted voice during transmission is prevented.

According to the second embodiment, it is possible to prevent interruption of transmission sound by digital processing without using a delay line constituted by circuit components such as a coil and a capacitor. Therefore, it is suitable for integration,
The communication device 1 can be reduced in size and cost.

In the first and second embodiments, a simplex communication device has been described as an example.
The present invention is not limited to this, and can be applied to a duplex communication device. Further, the present invention can be applied to a communication device including a transmission device using wired communication.

In the above-described embodiment, whether or not the microphone signal includes a voice signal is determined by the linear prediction analysis processing of the voice determination unit 9. However, the present invention is not limited to this. Other schemes can also be used.

Further, in this embodiment, the clock generator 3
Although the current consumption of the voice discriminating unit 9 is reduced by the start control of 6, the present invention is not limited to this. For example, the activation of the circuit components in the voice discriminating unit 9 may be controlled by a program process.

Further, in this embodiment, the pitch frequency discriminating section 35 performs the discriminating process for discriminating whether or not the fundamental frequency extracted by the fundamental frequency extractor 34 is the pitch frequency by software. You may process it. For example, a band-pass filter (either an analog band-pass filter or a digital band-pass filter) having a pass band from an upper limit (for example, 300 Hz) to a lower limit (for example, 60 Hz) of the pitch frequency may be used.
The same effect as that of the present embodiment can be obtained by disposing in place of the pitch frequency discriminating unit 35 and outputting a voice detection signal when the fundamental frequency passing through the band-pass filter is equal to or higher than a predetermined level. be able to.

[0057]

As described above, according to the communication apparatus of the present invention, the pitch frequency discriminating section determines whether or not the fundamental frequency of the input signal extracted by the linear predictor, correlator and fundamental frequency extractor is the pitch frequency. The control unit activates the transmission device when it is determined that the frequency is the pitch frequency, so that it is possible to prevent the transmission device from being activated by erroneously discriminating noise such as noise and wind noise as audio, and to prevent the audio from being activated. When a signal is input, the transmission device can be reliably started.

Also, a linear predictor, a correlator, and a fundamental frequency extractor
The output unit and pitch frequency discriminating unit
Start each time when there is no state from the state
Therefore, the determination process of the signal level determination unit is
Without waiting, the time required for the transmitter to start up is reduced
Be transformed into As a result, the transmission
Can be prevented from being cut off. Also slow
Even when using the delay means, the delay time of the delay means
The delay means can be reduced accordingly.
Can be typed.

The linear predictor, the correlator, the fundamental frequency extractor and the pitch frequency discriminator are activated only when the signal level of the input signal is judged to be higher than a predetermined level by the signal level discriminator. Therefore, when the level discrimination signal is not output from the level discrimination unit 13, the current consumption can be reduced accordingly, and as a result, the power consumption of the communication device can be reduced. Therefore, when the communication device is driven by a battery, a small battery can be used, so that the size of the communication device can be reduced, and when a battery having the same capacity as the conventional communication device is used. The communication device can be used continuously for a long time as compared with the conventional communication device.

Further, even if it takes some time until the fundamental frequency of the input signal is determined to be a pitch frequency within the pitch frequency band, the delay means delays the input signal by at least that much time and transmits the signal. Since the output is performed by the device, it is possible to reliably prevent the transmission voice from being cut off at the time of transmission.

Further, since the linear predictor, correlator, fundamental frequency extractor and pitch frequency discriminating unit are constituted by a DSP, the fundamental frequency is extracted and the fundamental frequency is adjusted from the upper limit to the lower limit of the pitch frequency band data. This is suitable for a determination process of determining whether or not the frequency is within the range, and the communication device can be downsized. In addition, even when the power consumption of the DSP is large, the DSP is started only when the signal level of the input signal is determined to be higher than the predetermined level by the signal level determination unit. Can be made extremely short, and as a result, current consumption in the DSP can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a communication device according to a first embodiment.

FIG. 2 is a block diagram of a level discrimination unit according to the first and second embodiments.

FIG. 3 is a block diagram of a communication device according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 communication device 4 audio input unit 9 audio discrimination unit 10 control unit 12 delay circuit 13 level discrimination unit 21 transmission unit 22 reception unit 31 register unit 32 linear predictor 33 correlator 34 fundamental frequency extractor 35 pitch frequency discrimination unit 36 clock generation Unit 51 A / D conversion unit 52 Memory 53 D / A conversion unit

Continuation of front page (56) References JP-A-59-152496 (JP, A) JP-A-5-210397 (JP, A) JP-A-60-83431 (JP, A) JP-A-6-152472 (JP) , A) JP-A-60-134631 (JP, A) JP-A-62-1151243 (JP, U) JP-A-3-90137 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) H04B 1/46 G10L 1/00

Claims (4)

(57) [Claims] A transmitter for transmitting an input signal input thereto to 1. A signal input means, and a control unit for the starting the transmission device when it contains audio signal to the input signal, the transmission
And a simplex communication device.
Receiving and outputting an incoming signal indicating reception of the received signal
A communication device comprising: a register unit for storing digital audio data obtained by analog-to-digital conversion of the input signal; and a linear prediction analysis process based on the digital audio data stored in the register unit. A linear predictor for obtaining a plurality of prediction errors, a correlator for calculating an autocorrelation of the obtained plurality of prediction errors, and a fundamental frequency extractor for extracting a fundamental frequency of the input signal based on the calculated autocorrelation When,
A memory that stores, from the upper limit to the lower limit of the fundamental frequency band of a voiced sound accompanied by vocal cord vibration as a pitch frequency band,
A pitch frequency determination unit that determines whether the extracted fundamental frequency is a pitch frequency within a pitch frequency band stored by the memory, wherein the control unit determines that the extracted fundamental frequency is the pitch frequency. When the discriminating unit determines that the pitch frequency, the transmitter is activated , the linear predictor, the correlator, the fundamental frequency
The extractor and the pitch frequency discriminating unit are provided with the incoming signal
Is activated when the status changes from
Communication device characterized that you have configured to movement. 2. The apparatus according to claim 1, further comprising a signal level determination unit configured to determine whether a signal level of the input signal is equal to or higher than a predetermined level, wherein the linear predictor, the correlator, the fundamental frequency extractor, and the pitch frequency are provided. 2. The communication device according to claim 1, wherein the determination unit is configured to be activated when the input signal is determined to be equal to or higher than a predetermined level by the signal level determination unit. A delay unit for delaying an input signal input to the signal input unit and outputting the delayed signal to the transmitting apparatus, wherein a delay time of the delay unit is equal to a delay time of a first input signal of the input signals. From the time of input to the signal input means,
The time difference is set to be equal to or greater than the time difference until the control unit activates the transmission device.
The communication device as described. Wherein said linear predictor, the correlator, the fundamental frequency extractor and the pitch frequency determination unit, any one of claims 1 to 3, characterized in that it is constituted by a digital signal processor The communication device according to claim 1.