JPH10116099A - Sound start sound recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a malfunction due to an external noise by deciding sound/ silence based on a sound signal encoded in frame of a prescribed time length, controlling start/stop of sound recording and setting a characteristic of a filter limiting a frequency band of an input sound according to set sound input sensitivity. SOLUTION: A main control circuit 6 decides whether the input sound is the sound or the silence based on the sound signal encoded in frame of the prescribed time length. Further, a variable resistor 28 revises the timing of the start or stop of the sound recording based on the output of the main control circuit 6. Further, the variable resistor 28 revises a threshold value of a reference level when the main control circuit 6 decides the sound/silence, and sets the input sensitivity of the input sound together with the main control circuit 6. Then, when the sound input sensitivity is set in high, a filter characteristic of a band-pass filter 50 is varied, and a frequency band is narrowed, and the band of the sound signal inputted to a digital signal processing part 5 is limited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice-activated recording device, and more particularly to a voice-activated recording device that processes an input audio signal and records the processed audio signal on a recording medium.

[0002]

2. Description of the Related Art In recent years, an audio signal obtained by a microphone or the like is converted into a digital signal, which is recorded in, for example, a semiconductor memory. At the time of reproduction, the audio signal is read from the semiconductor memory and converted into an analog signal. A digital information recording / reproducing apparatus called a so-called digital recorder which outputs sound as a sound by a speaker or the like has been developed. Japanese Patent Application Laid-Open No. 63-259700 discloses a digital information recording / reproducing apparatus as described above.

In general, in a storage / reproduction device such as the above-described digital information recording / reproduction device, highly efficient encoding is performed on a digitized audio signal in order to save the amount of data recorded in a semiconductor memory. To minimize the amount of data generated. In addition, a method of compressing silence for high-efficiency encoding has been proposed. In general, silence is included even in ordinary conversation, and when the silence compression is performed, the bit rate is reduced by about 30%. It is known that it can be lowered.

[0004]

However, according to the above-mentioned technical means, recording may be started erroneously at the time of recording due to environmental noise such as opening and closing of a door or coughing, or may be stopped due to noise when it should be stopped. There was a problem that it became impossible. In addition, there is also a problem that the head is cut off at the start of recording.

The present invention has been made in view of such a problem, and has as its object to provide a voice-activated recording device that does not malfunction due to external noise.

[0006]

In order to achieve the above object, a first voice-activated recording apparatus of the present invention determines whether an input voice is a sound or a silent sound for a predetermined time length. Audio level determining means for determining based on an audio signal encoded in frame units, recording control means for controlling start or stop of recording based on an output of the audio level determining means, and input sensitivity of input audio. Voice input sensitivity setting means to be set; filter means for limiting a frequency band of voice input to the voice level determination means; and filter characteristics of the filter means according to voice input sensitivity set by the voice input sensitivity setting means. Filter characteristic setting means for setting.

In order to achieve the above object, a second aspect of the present invention
The voice-activated recording device of the first aspect is characterized in that, in the first voice-activated recording device, a filter characteristic of the filter means is set so as to narrow a frequency band as the voice input sensitivity increases.

[0008] In order to achieve the above object, a third aspect of the present invention is provided.
The voice activated recording device of the first aspect is characterized in that, in the first voice activated recording device, the filter means limits a frequency band of the digital voice signal.

[0009] In the first voice activated recording device,
In the sound level determination means, it is determined whether the input voice is voiced or silent based on a voice signal encoded in frame units having a predetermined time length, and in the recording control means,
The start or stop of recording is controlled based on the output of the audio level determination means. Further, according to the voice input sensitivity set by the voice input sensitivity setting means, the filter characteristic setting means sets the filter characteristic of the filter means for limiting the frequency band of the voice input to the voice level determination means.

[0010] The second voice-activated recording device includes the first voice-activated recording device.
In the voice activated recording device of the above, the filter characteristics of the filter means are set so as to narrow the frequency band as the voice input sensitivity increases.

[0011] The third voice-activated recording device may include the first voice-activated recording device.
In the voice activated recording device of the above, the filter means limits a frequency band of the digital voice signal.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block circuit diagram showing a configuration of a voice activated recording apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the voice-activated recording apparatus according to the present embodiment includes a microphone 1, and a voice signal from the microphone 1 is supplied to an amplifier (AMP) 2, a low-pass filter (LPF), and an analog switch 26. Analog /
The data is input to a digital (A / D) converter 4. The output terminal of the A / D converter 4 detects voice compression and decompression, time axis compression means, means for detecting or predicting an input signal level, conditional time axis compression means, and a signal input at high speed. Signal processing section (DS) built in the main control circuit 6 which is a component of the data processing means.
P) 5, it is connected to the first terminal D1 of the main control circuit 6.

The main control circuit 6 also serves as a sound level judging means for judging whether or not the level of the inputted sound is a sound level satisfying a predetermined condition. The audio level satisfying the predetermined condition is
It means a sound level above a certain reference level or below a reference level. For example, it is possible to determine that there is sound when the level is higher than a certain reference level, or to determine that there is no sound when the level is lower than a certain reference level. Therefore, by providing a certain reference level in this way, it is possible to determine whether the input voice is sound or no sound.

It is to be noted that judging "silence" does not necessarily mean that the sound level is zero, but as described above, a certain reference level is set, and if the sound level is lower than this level, it is determined that "no sound". By making the determination, it is possible to treat it as synonymous with “silence”.

Further, the main control circuit 6 determines the above-mentioned audio level in units of frames for encoding audio signals.

In addition, the main control circuit 6 also functions as a continuity monitoring means for monitoring the continuity of a frame of a sound level satisfying the above predetermined condition, for example, a voiced frame or a silenced frame. I have. The frame unit will be described later in detail.

The main control circuit 6 also functions as recording control means for controlling the start or stop of recording based on the result of monitoring the continuity.

On the other hand, the voice-activated recording apparatus according to the present embodiment includes a speaker 13 as a voice output means, and the speaker 13 includes an analog switch 30 and an amplifier (AMP).
12, is connected to a second terminal D2 of the main control circuit 6 via a digital / analog (D / A) converter 11.

The analog switch 26 is connected to the main control circuit 6
Is controlled to be turned on during recording. The analog switch 30
Is connected to the control terminal E2 of the main control circuit 6 and is controlled to be turned on during reproduction.

An analog switch 27 is connected between the AMP 12 and the analog switch 30, and the analog switch 27 further includes a variable resistor (VR).
28 voltage supply terminals. The analog switch 27 is connected to the control terminal E3 of the main control circuit 6, and is controlled to be turned on when the state of the variable resistor 28 is detected.

On the other hand, an analog switch 29 is connected between the A / D converter 4 and the analog switch 26. The analog switch 29 is further connected to an intermediate tap terminal of the variable resistor (VR) 28. You. The analog switch 29 is connected to the control terminal E4 of the main control circuit 6, and is controlled to be turned on when the state of the variable resistor 28 is detected.

The variable resistor 28 changes the threshold of the reference level when the main control circuit 6 as the sound level judging means judges the presence or absence of sound as described above.
That is, it is used to set the input sensitivity of the sound input from the microphone 1. At this time, the main control circuit 6 and the variable resistor 28 function as a voice input sensitivity setting unit.

The digital signal processing unit 5 includes:
A band pass filter (BPF) 50 for extracting an optimal frequency band from an input audio signal is built in. The band-pass filter 50 functions as a filter unit whose characteristics are changed by the main control circuit 6 as a filter characteristic setting unit in conjunction with the voice input sensitivity. That is, when the voice input sensitivity is high, noise such as background noise is also likely to be mixed. Therefore, in the present embodiment, when the voice input sensitivity is set high, the filter characteristics of the bandpass filter 50 are changed. Thus, the frequency band is narrowed, and the band of the audio signal input to the digital signal processing unit 5 is limited. In addition,
Details will be described later.

Further, the variable resistor 28 is used by the main control circuit 6 to change the timing at which recording is started or stopped by changing the number of predetermined frames which are continuously detected. Used to change At this time, the main control circuit 6 and the variable resistor 28
Serves as a recording timing changing means.

The third terminal D3 of the main control circuit 6 is connected to the memory control circuit 7, and the fourth terminal D4 is connected to the semiconductor memory unit 10 which can be attached to and detached from the recording / reproducing apparatus.

The fifth terminal D5 of the main control circuit 6 serves as a data transmitting means for transmitting data recorded in the semiconductor memory unit 10 or a light emitting diode (output) as an output of an output signal indicating that the signal can be received. (LED) 17. When the LED 17 is used only for data transmission / reception, an infrared light emitting diode is used. However, the LED 17 is also used as a display which emits light when sound is input or output during recording or reproduction. Therefore, the LED 17 contains a large amount of visible light component and has a peak wavelength of, for example, 500 nm to 1000 nm, preferably 600 nm.
An infrared light emitting diode having a relatively low wavelength of about 800 nm is used.

Further, the sixth terminal D6 of the main control circuit 6
Is connected to the display 8 via the drive circuit 9.

The seventh terminal D7 of the main control circuit 6 is connected to a PI through a voltage comparator (COMP) 16.
It is connected to the junction between the N diode 14 and the resistor 15. Here, the PIN diode 14, the voltage comparison comparator 16, and the resistor 15 constitute data receiving means or means for receiving a data transfer start signal.

The eighth terminal of the main control circuit 6 is DC-DC
It is connected to a battery (BAT) 18 via a converter 20 and a main power switch 19. The DC-DC converter 20 outputs a boosted voltage from the battery 18 and supplies a stable power supply voltage to each means, and at the same time, an eighth terminal D
8, a signal is sent to inform whether the voltage of the battery 18 is below a certain value. Thus, the main control circuit 6 detects the state of consumption of the battery 18.

Further, a relay 25 is connected in parallel with the power switch 19 so that even if the power switch 19 is turned off, the power supply is not stopped immediately. The main control circuit 6 is connected to the main control circuit 6 so that when the power switch 19 is turned off so that the power switch 19 is turned off, the voltage of the battery 18 can be detected.

Further, an anode of a diode 21 is connected to a ninth terminal D9 of the main control circuit 6, and a parallel circuit of a capacitor 22 and a resistor 23 is connected between the cathode of the diode 21 and the ground. Have been.
Further, the cathode of the diode 21 is connected to the base of the transistor 24. The collector of the transistor 24 is connected to the junction between the microphone 1 and the microphone amplifier 2, and the emitter is connected to ground.

Further, the main control circuit 6 has a recording button (R
EC), play button (PL), stop button (ST), fast forward button (FF), fast reverse button (REW), I (I
nstruction) mark buttons I, E (END)
Operation buttons such as a mark button E and a voice activation (voice active detector) button VAD are connected.

As shown in FIG. 1, the semiconductor memory section 10 includes a temporary recording medium section 100a and a main recording medium section 10a.
0b. Usually, a flash memory is used for the main recording medium unit 100b, but a magneto-optical disk, a magnetic disk, a magnetic tape, or the like may be used. The temporary recording medium unit 100a has an SRAM, a DRAM,
EEPROM, high dielectric memory, flash memory, etc.
One that can read and write at a relatively high speed as compared with the main recording medium unit 100b is used. In the present embodiment, an SRAM is used for the temporary recording medium unit 100a, and the main recording medium unit 100a is used.
For b, a flash memory is used.

The address, which is the information indicating the recording position of the audio information, is stored in the detachable semiconductor memory unit 10, but is not shown in the semiconductor control unit 7 provided on the recording / reproducing side. It may be recorded in a memory (in the main control circuit 6).

Here, the I mark and the E mark are as follows. That is, since a plurality of documents are recorded on a recording medium, in this type of audio information recording apparatus, when a document recorder operates the I mark button I at the time of recording, a plurality of documents recorded on the recording medium are operated. An index (Instruction (I) mark) indicating a priority relationship between the typist and an instruction index mark for a secretary can be recorded. It is possible to indicate a relationship. In addition, an index mark called an end (E) mark can be recorded by operating the E mark button E to indicate a break between a plurality of documents.

The recording of the present embodiment configured as described above,
The reproduction operation will be briefly described.

At the time of recording, the analog audio signal obtained from the microphone 1 is amplified by the microphone amplifier 2, the frequency band is limited through the low-pass filter 3, and then the digital signal is converted by the A / D converter 4. To the digital signal processing (DS) inside the main control circuit 6.
P) Input to section 5.

Here, when the signal input from the microphone 1 is larger than a predetermined reference level, for example, when the signal is larger than -6 dB of the maximum range of the A / D converter 4, the signal is connected to the ninth terminal D9 of the main control circuit 6. Diode 21
, A charge is accumulated in the capacitor 22 and a voltage is applied to the transistor 24. Then, the impedance between the microphone amplifier 2, the transistor 24, and the ground changes, the signal input to the microphone amplifier 2 is limited, and the gain is adjusted. The electric charge stored in the capacitor 22 is gradually discharged by the resistor 23.

In response to the operation of the plurality of operation buttons and switches of the main control circuit 6, the digital data compressed by the digital signal processing section 5 is output through the third terminal D3 and the fourth terminal D4 of the main control circuit 6. The data is recorded in the semiconductor memory unit 10.

When performing reproduction, the main control circuit 6 reads out the data recorded in the semiconductor memory unit 10 and supplies it to the digital signal processing unit 5 for expansion, and the digital signal processing unit 5 expands the data. The audio data is converted into an analog signal by the D / A converter 11, amplified by the AMP 12, and output from the speaker 13 as audio. Further, the main control circuit 6 controls the drive circuit 9 to cause the display 8 to display various information such as an operation mode.

Next, the operation of the voice-activated recording apparatus according to this embodiment configured as described above will be described in detail.

FIG. 2 is a flowchart showing the main operation of the voice-activated recording apparatus according to this embodiment, which will be described as the operation of the main control circuit 6.

When the battery 18 is set and power is supplied, the main control circuit 6 starts an operation as shown in the flowchart. That is, first, the external conditions of the main control circuit 6 and the initial setting of the internal storage unit are performed (step S1). After completing the initial setting, the main control circuit 6 detects whether or not the power supply voltage of the battery 18 is a rated value (step S2). The rated value is set to, for example, 1 V. The main control circuit 6 determines whether the power supply voltage of the battery 18 is 1 V or more,
Whether the impedance of the battery 18 is higher than the rated value is detected from the current flowing through the DC-DC converter 8 based on information from the DC-DC converter 20. At this time, a signal for determining the state of the battery 18 is input to the eighth terminal D8 of the main control circuit 6, so that it is possible to detect whether or not the battery 18 has a usable capacity ( Step S2).

As a result of the detection in step S2, when the main control circuit 6 detects that the battery 18 is not in a usable state, the main control circuit 6 stops the power supply to the entire voice-activated recording device, and And between each circuit,
A switch (not shown) is turned off to display through the drive circuit 9 and the display 8 that the battery 18 has no capacity.
If the main control circuit 6 detects that the battery 18 is in a usable state as a result of the detection in step S2,
The relay switch 25 is turned on, and thereafter, it is determined whether or not to perform data transfer based on whether the relay switch 25 or the stop button ST and the fast forward button FF are simultaneously pressed (step S3). Move to transfer processing.

In the case of NO in step S3, the information of the index section is read from the semiconductor memory section 10, which is a recording medium (memory section). Thereafter, the main control circuit 6 determines, based on the data read from the semiconductor memory unit 10, whether the semiconductor memory unit 10 has already recorded the index normally, that is, whether the format of the semiconductor memory unit 10 is normal. (Step S4).

In step S4, if a non-formatted semiconductor memory unit 10 is inserted, it is determined that the semiconductor memory unit 10 is not normal, and the semiconductor memory unit 10
Then, it is confirmed whether or not to execute a memory format (initialization), which is a process of inputting information indicating a use condition to the index section 10A and inputting "0" to the audio data section 10B (step S5). That is, by controlling the drive circuit 9,
Display 8 confirms whether to format the memory
To be performed.

Here, if the button for confirming the memory format processing (also used as the recording button REC) is pressed, the main control circuit 6 formats (initializes) the semiconductor memory unit 10 (step S6), After the completion of the format, the drive circuit 9 is controlled to display the completion of the initial setting on the display 8 (step S7).

In step S5, when a button for confirming not to format the memory (also used as a stop button STOP) is pressed, the main control circuit 6 controls the drive circuit 9 to display the semiconductor on the display 8. In addition to displaying that the memory unit 10 is not normal, it also indicates that the semiconductor memory unit 10 should be replaced. Further, a switch (not shown) provided between the battery 18 for supplying power to the entire voice activated recording device and each circuit is turned off (step S8). After that, it waits for the main power switch 19 to be turned off to replace the semiconductor memory unit 10 (step S9).
When it is detected that 9 has been turned off, the process proceeds to step S22.

On the other hand, in the case where the initialization has been normally completed in the semiconductor memory unit 10, after the initialization is displayed, the current operation is performed based on the information read from the index unit (step S10). Thereafter, the main control circuit 6 puts each circuit in a waiting state while detecting whether any of the operation buttons of the voice activated recording device is pressed (Step S).
11).

In step S11, when the main control circuit 6 detects that any operation button has been pressed, it first detects whether or not the operated button is the recording button REC (step S12). When REC is pressed, the digital signal processing unit 5 is controlled to compress the audio information input from the A / D converter 4, and the memory control circuit 7
Is recorded in the audio data section of the semiconductor memory section 10 (step S13).

If the operated button is not the record button REC, the main control circuit 6 sets the next play button PLA.
Y is detected (step S14). Here, if the play button PLAY is pressed, the main control circuit 6 controls the memory control circuit 7 to read out the recorded data from the audio data section 10B of the semiconductor memory section 10, and the digital signal processing section 5 and performs a decompression process, and enters a reproduction process of transmitting audio information to the D / A converter 11 (step S
15).

If the play button PLAY has not been pressed, the main control circuit 6 detects whether or not the fast forward button FF has been pressed (step S16). If the fast-forward button FF has been pressed, the main control circuit 6 enters a fast-forward process for sequentially fast-forwarding the operating position at an appropriate speed, for example, 20 times the speed of reproduction (step S17).

If the fast-forward button FF has not been pressed, the main control circuit 6 detects whether or not the fast-return button REW has been pressed (step S1).
8). And if the fast reverse button REW is pressed,
A fast-return process for moving the operating position at the same speed as in the fast-forward operation is entered (step S19).

Steps S13, S15, S17, S
When the stop button STOP is pressed in each of the processes 19, the main control circuit 6 exits from each of the processes and returns to the step S11.

If the operated button is not a button for recording, reproducing, fast-forwarding, rewinding, etc., the main control circuit 6 turns off the power or detects the state of various setting buttons (step S20). In this step S20, when the power of the main power switch 19 is turned off, the main control circuit 6
Updates the information in the index section 10A of the semiconductor memory section 10 by controlling the memory control circuit 7, and stores the index information stored in the storage section (not shown) inside the main control circuit 6 in the semiconductor memory section 10. It is recorded in the index section (step S21). When the index transfer process is completed, the main control circuit 6 controls the entire voice-activated recording device, that is, the relay switch 2 to which each circuit power is supplied.
5 is turned off (step S22).

In step S20, when it is determined that the main power switch 19 is not turned off, the main control circuit 6 detects the setting button, stores the state of the setting button in the internal storage unit, and then proceeds to step S11. Return to The setting button may be provided exclusively, but is not provided exclusively in this embodiment. That is, the recording button RE
C, play button PLAY, stop button STOP, fast forward button FF, fast reverse button REW, I mark button I,
E mark button E, voice activation (silence compression) button VAD
By pressing several buttons at the same time, the function as the setting button can be substituted.

In the present embodiment, the condition setting of the parameters of the band-pass filter 50 (see FIG. 1) is changed in conjunction with the input sensitivity (microphone sensitivity) of the sound input from the microphone 1. I have. Less than,
The voice input sensitivity (microphone sensitivity) setting operation will be described with reference to FIG.

FIG. 3 is a flowchart showing a microphone sensitivity setting operation in the voice activated recording device of the present embodiment.

In the voice-activated recording apparatus of this embodiment, the voice input sensitivity from the microphone 1 can be changed in the range from 0 dB to -40 dB in conjunction with the variable resistor 28. Now, as an operation example, a case where the microphone sensitivity is changed in a range from 0 dB to −20 dB will be described.

In the present embodiment, for example, when the sampling frequency is 8 KHz, the condition setting value of the parameter of the band-pass filter 50 is such that when the microphone sensitivity is -20 dB, the frequency band has a width of 100 Hz to 3.5 KHz. Is 0 dB, the frequency band is 300 Hz to 3K.
It is set to have a width of Hz. This is because if the sensitivity of the microphone is increased, background noise is more likely to be mixed in with the microphone sensitivity, so that only the voice input can be detected. The microphone sensitivity and the condition set value of the parameter of the bandpass filter change depending on the sampling frequency and frequency band of the input signal.

As shown in FIG. 3, when a voice is inputted, the current voice input sensitivity (microphone sensitivity) is detected (step S31), and it is detected whether or not the microphone sensitivity is 0 dB (step S31). S32). Here, microphone sensitivity = 0d
In the case of B, the filter characteristic of the bandpass filter 50 is set to 3
A frequency band of 00 Hz to 3 kHz is set (step S36).

If the microphone sensitivity is not 0 dB in step S32, then -20 dB <microphone sensitivity <
0 dB is detected (step S33), and if it is within this range, the lower limit of the frequency band of the band-pass filter 50 is set to 100 Hz to 300 Hz according to the microphone sensitivity.
, And the upper limit of the frequency band of the band-pass filter 50 is set in the range of 3 kHz to 3.5 kHz (step S37).

If it is determined in step S33 that the microphone sensitivity is not within the range of -20 dB <microphone sensitivity <0 dB, it is next detected whether or not the microphone sensitivity is -20 dB (step S34), and the microphone sensitivity is -20 dB. , The filter characteristic of the band-pass filter 50 is set to 3 kHz.
The frequency band is set to z to 3.5 kHz (step S3
5) If not -20 dB, the process returns to step S31.

As described above, the voice-activated recording apparatus according to the present embodiment can considerably reduce the amount of background noise. As a result, it is possible to prevent misjudgment of the presence / absence of input sound due to extraneous noise or the like.Therefore, recording is started or mistakenly initiated by extraneous noise such as environmental noise such as opening / closing of a door or coughing. There is no risk of stopping.

Further, the present invention has the effect of preventing head breaks and the like, which are likely to occur at the start of recording, preventing waste of use of the recording medium, and improving the efficiency of the recording medium when a speaker with a lot of silence uses it.

In this embodiment, the band-pass filter is used for setting the frequency band. However, the present invention is not limited to this. For example, the cut-off frequency of the unit low-pass filter or the cut-off characteristic (cut-off angle) may be changed. The same effect can be obtained by changing only the cutoff characteristic (cutoff angle).

Further, in this embodiment, a variable resistor is used as the means for setting the voice input sensitivity. However, it is apparent that switches corresponding to several types of fixed resistors may be provided and substituted by the variable resistors.

[Appendix] According to the embodiment of the present invention as described in detail above, the following configuration can be obtained. (1) A sound level determining means for determining whether a sound to be input is sound or no sound in units of frames, and a recording control for controlling start or stop of recording based on an output of the sound level determining means. Means, voice input sensitivity setting means for setting the input sensitivity of the voice to be input, filter means for limiting the frequency band of the voice to be input to the voice level determination means, and voice input sensitivity to be set by the voice input sensitivity setting means And a filter characteristic setting means for setting a filter characteristic of the filter means in accordance with the above.

(2) The voice-activated recording apparatus according to (1), wherein the filter characteristics of the filter means are set so as to narrow the frequency band as the voice input sensitivity increases.

(3) The filter means limits the frequency band of the digital audio signal (1).
A voice-activated recording device according to claim 1.

(4) The voice-activated recording device according to (1), (2) or (3), wherein the voice input sensitivity setting means includes a variable resistor for adjusting at least voice input sensitivity.

(5) The voice-activated recording device according to (1), (2) or (3), wherein the voice input sensitivity setting means includes at least a switch means for switching the voice input sensitivity.

According to the voice-activated recording device described in (1), a voice-activated recording device that does not malfunction due to external noise or the like can be provided.

According to the voice activated recording device described in the above (2), it is possible to provide a voice activated recording device which is more convenient and more accurately prevents malfunctions due to external noises and the like.

According to the voice activated recording device described in the above (3), it is possible to provide a voice activated recording device capable of more accurately preventing a malfunction due to external noise or the like.

According to the voice-activated recording device described in the above (4), it is possible to provide a voice-activated recording device that is more convenient to use and that more accurately prevents malfunction due to external noise and the like.

According to the voice activated recording device described in the above (5), it is possible to provide a voice activated recording device that is more convenient to use and more accurately prevents malfunctions due to external noise and the like.

[0080]

As described above, according to the first aspect of the present invention, it is possible to provide a voice-activated recording apparatus that does not malfunction due to external noise or the like.

Further, according to the second aspect of the present invention, it is possible to provide a voice-activated recording apparatus which is more convenient and more accurately prevents malfunctions due to external noise and the like.

According to the third aspect of the present invention,
It is possible to provide a voice-activated recording device that more accurately prevents malfunction due to external noise and the like.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a configuration of a voice activated recording device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main operation in the voice activated recording device of the embodiment.

FIG. 3 is a flowchart showing a microphone sensitivity setting operation in the voice activated recording device of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Microphone 2 ... Microphone amplifier 3 ... Low-pass filter 4 ... A / D converter 5 ... Digital signal processing unit 6 ... Main control circuit 7 ... Memory control circuit 10 ... Semiconductor memory unit 11 ... D / A converter 28 ... Variable resistance 50 ... Band pass filter

Claims (3)

[Claims] 1. A sound level determining means for determining whether a sound to be input is sound or no sound based on a sound signal encoded in a frame unit having a predetermined time length, Recording control means for controlling the start or stop of recording based on the output of the means, voice input sensitivity setting means for setting the input sensitivity of the input voice, and limiting the frequency band of the voice input to the voice level determination means. A voice-activated recording device comprising: a filter unit; and a filter characteristic setting unit configured to set a filter characteristic of the filter unit according to a voice input sensitivity set by the voice input sensitivity setting unit. 2. The voice-activated recording apparatus according to claim 1, wherein the filter characteristic of said filter means is set so as to narrow a frequency band as said voice input sensitivity increases. 3. The apparatus according to claim 1, wherein said filter means limits a frequency band of the digital audio signal.