JPH07129198A - Sound recording device and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the voice from being hard to hear even in reproducing at a high speed as over twice. CONSTITUTION:A main control circuit 8 controls an address control circuit 9 at the time of reproducing, and the data of one block is read from a memory part 10, and further the data of another block is read when a quick listening process is conducted. If these two pieces of block data contain a voiceless sound flag, data transfer process to a DSP part 5 is conducted, and if no voiceless sound flag, a direction to perform a temporal axis compression in TDHS system is given to the DSP part 5, and data transfer to the DSP part 5 is conducted. Thereby the temporal axis compression is made by TDHS system or through partial thinning in the case of voice sound or not of sound, while such as operation is performed in the case of voiceless sound division that the temporal axis compression is not made or that the ratio of temporal axis compression is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can convert an analog signal input from a microphone into a digital signal, record it on a recording medium such as a memory, convert the recorded signal into an analog signal and reproduce it by a speaker. The present invention relates to an audio recording device and an audio reproducing device, and more particularly, to an audio recording and reproducing device having a high-speed reproduction function that enables high-speed and fast listening.

[0002]

2. Description of the Related Art Generally, dictation recording is one of the applications of tape recorders. For example, record the contents of the letter to be sent in advance on the tape with a tape recorder,
Give this recorded tape to a secretary, etc., and play this tape and type a letter while listening to the voice, or record the contents of the meeting and listen to this recording later and discuss There are various uses such as making a record.

However, the type speed has a great individual difference depending on the skill of the typist. Therefore, when the sound recorded on the tape is reproduced to perform the type, the rotation speed of the tape is changed according to the type speed. At this time, if the reproduction speed is slowed down, the pitch (tone) of the voice is lowered and the clarity of the voice is lowered. On the contrary, if the reproduction speed is increased, the pitch of the voice is increased and the clarity is also lowered.

Conventionally, in order to solve this problem, a method called Variable Speech Control for thinning out an audio signal, for example, JP-A-1-232400 or JP-A-1-232400.
As disclosed in Japanese Patent No. 233835, Time Domain Harmonic for extracting a pitch period of a voice input signal and applying a weighting window function to voice data of two pitch periods according to the pitch period to perform time axis compression. Scale (TDHS) method has been used.

Further, in recent years, in response to the demand for miniaturization of the apparatus, for example, as disclosed in Japanese Patent Laid-Open No. 63-259700, an apparatus using a semiconductor memory instead of a magnetic tape as a recording medium has been developed. Has been done.

FIG. 8 shows a time axis compression process of the TDHS system as described above. This example shows a case where a sound signal for two pitches having periodicity is compressed to one pitch. First, the audio signal Sin for two pitches is taken in, the weighted window function W (m) is applied to the audio signal of the front period P1, and the weight window opposite to the front period P1 is applied to the rear period P2. Function 1-
The time axis is compressed by multiplying W (m) and adding each to make one Sout.

[0007]

However, such T
In the DHS system, if the voiced sound portion, the unvoiced sound portion, and the unvoiced sound portion are uniformly time-axis-compressed, the sound signals of the respective portions are averaged, and it becomes difficult to hear when the speed is about double speed or more. In particular, in the section including the unvoiced sound portion, there is a problem that it becomes difficult to hear when the time axis compression is performed on the frictional portion or the explosive portion.

The present invention has been made in view of the above points, and an object of the present invention is to provide an audio recording apparatus and an audio reproducing apparatus in which the audio is not difficult to hear even at the time of high speed reproduction of about double speed or more. To do.

[0009]

In order to achieve the above object, an audio reproducing apparatus according to the present invention comprises an audio reproducing means for reproducing a digital audio signal, and an audio signal successively reproduced by the audio reproducing means. Discrimination means for discriminating between voiced sound, unvoiced sound, and silence, and when the voice signal is reproduced at a higher speed than usual, the discrimination means relates to voiced sound and silence. The time axis is compressed for the voice signal determined to be, and the time axis is not compressed for the voice signal determined to be related to unvoiced sound. And a time axis compression means for performing time axis compression at a lower compression rate.

Further, in the voice recording apparatus according to the present invention, whether the voice recording means for digitizing and recording the voice signal on a predetermined recording medium and the voice signal successively recorded by the voice recording means relate to voiced sound. A detection means for detecting whether it is unvoiced or unvoiced, and related information recording means for recording the information detected by the detection means in the recording medium in association with the audio signal. There is.

Further, in another audio reproducing apparatus according to the present invention, the audio reproducing means for reproducing a digital audio signal and the audio signals successively reproduced by the audio reproducing means are related to voiced sound or unvoiced sound. Whether or not the voice signal is reproduced at a speed higher than normal when the voice signal is reproduced at a higher speed than usual, the time axis of the voice signal determined to be related to the voiced sound is compressed by the above-mentioned discrimination means. ,
The audio signal determined to be unvoiced is provided with conditional time axis compression means for performing time axis compression according to a predetermined condition.

Further, another audio reproducing apparatus according to the present invention comprises an audio reproducing means for reproducing a digital audio signal,
When the audio signal sequentially reproduced by the audio reproducing means is related to voiced sound, unvoiced sound, or unvoiced sound, and a sound signal is reproduced at a higher speed than usual, A data processing unit that compresses the time axis for a voice signal that is determined to be related to voiced sound by the determination unit and performs a data thinning process for a voice signal that is determined to be related to silence. I have it.

[0013]

In the voice reproducing apparatus according to the present invention, the discriminating means is
It is determined whether the digital audio signal sequentially reproduced by the audio reproducing means is related to voiced sound, unvoiced sound, or unvoiced sound. When the audio signal is reproduced at a higher speed than usual, the time axis compression unit compresses the time axis of the audio signal that is discriminated by the discriminating unit as to the voiced sound and the silent voice, and The time axis is not compressed for the audio signal that is determined to be the one, or the time axis compression is performed at a compression rate lower than the time axis compression rate of the voice signal related to voiced sound and silence.

Further, in the audio recording apparatus according to the present invention, when the audio recording means for digitizing and recording the audio signal on the predetermined recording medium successively records the audio signal, the detecting means makes the audio signal into a voiced sound. It is detected whether it is related, unvoiced sound, or silent sound. Then, the related information recording means records the information detected by the detecting means in the recording medium in association with the audio signal.

Further, in another audio reproducing apparatus according to the present invention, the discriminating means determines whether the digital audio signals successively reproduced by the audio reproducing means are voiced sound, unvoiced sound, or unvoiced sound. To determine. When the audio signal is reproduced at a higher speed than usual, the conditional time axis compression means compresses the time axis of the audio signal determined to be related to voiced sound by the determination means,
A voice signal determined to be unvoiced is compressed on the time axis according to a predetermined condition.

In still another audio reproducing apparatus according to the present invention, the discriminating means determines whether the digital audio signals sequentially reproduced by the audio reproducing means are voiced sound, unvoiced sound, or unvoiced sound. To determine if. And
When the audio signal is reproduced at a higher speed than usual, the data processing unit determines that the audio signal, which is determined to be related to voiced sound by the determining unit, is compressed in the time axis and is related to silence. Data thinning processing is performed on the generated audio signal.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an audio recording / reproducing apparatus as an embodiment of the present invention. In this voice recording / reproducing apparatus, the analog signal obtained from the microphone 1 is
The signal is amplified by an amplifier (AMP) 2 and passed through a low pass filter (LPF) 3 and then analog / digital (A /
D) Converted into a digital signal by the converter 4, and input to the digital signal processing (DSP) unit 5 which is a constituent element of the discriminating means, the time base compression means, the detection means, the conditional time base compression means, and the data processing means. To do. This DSP unit 5
Audio is compressed during recording operation and expanded during playback operation. The operation of the DSP unit 5 is controlled by the control circuit 6, and the compressed audio is input / output (I / O) buffer 7
To the main control circuit 8 via.

The main control circuit 8, which is a constituent element of the audio reproducing means, the audio recording means, and the related information recording means, responds to the operation of a plurality of operation buttons and switches by the DSP section 5 described above.
Then, it controls the operation of the address control circuit 9 and the semiconductor memory unit 10 as a recording medium detachably attached to the recording / reproducing apparatus. That is, an appropriate address signal is given to the address control circuit 9, the voice data supplied from the data I / O buffer 7 is recorded in the memory section 10, or the data recorded in the memory section 10 is read to read the data I It is supplied to the DSP unit 5 via the / O buffer 7.

The address, which is the information indicating the recording position of the audio information, may be stored in the removable semiconductor memory unit 10, and is not associated with the address control circuit provided on the recording / reproducing apparatus side. It may be stored in the illustrated semiconductor memory (internal storage unit).

The read data expanded by the DSP unit 5 is converted into an analog signal by the digital / analog (D / A) converter 11, amplified by the amplifier (AMP) 12, and then output to the speaker 13. .

The main control circuit 8 includes a drive circuit 14
Is controlled to display various information such as the operation mode on the display unit 15. The memory unit 10 in FIG.
It has a recording structure as shown in. That is, the memory space is roughly divided into the index section 10A and the audio data section 10B. The index unit 10A includes the operation start position information 10A1 and the operation end position information 10 for each of the plurality of voice message files 10B1, 10B2, 10B3, ... Recorded in the voice data unit 10B.
A2, other code modes, operating conditions, etc. are recorded. In addition, operation position information 10A3 indicating the current operation position with respect to the audio data portion 10B is recorded.

The buttons connected to the main control circuit 8 are a record button REC, a play button PL, a stop button ST, a fast forward button FF, and a return button REW, I.
There are mark buttons I and E, a mark button E, a voice activation (voice active detector) button VAD, and a main power switch 16 between the battery BAT and the switch. Here, the I mark and the E mark are as follows. That is, since a plurality of sentences are recorded on the recording medium, in this type of audio recording / reproducing apparatus, a plurality of sentences recorded on the recording medium can be operated by operating the I mark button I at the time of recording by the sentence recorder. It is possible to record an instruction (I) mark, which indicates the priority relationship between the typists and an index mark for instruction for a secretary, and the sentence recorder can use the I mark to concretely record by voice. It is possible to indicate a priority relationship. Further, an index mark called an end (E) mark can be recorded by operating the E mark button E in order to indicate a division between a plurality of documents.

Next, the operation of the voice recording / reproducing apparatus having such a configuration will be described in detail. When the battery BAT is set and power is supplied to the main control circuit 8, the main control circuit 8 detects it by voltage detection and starts the operation as shown in the flowchart of FIG.

That is, first, the external conditions of the main control circuit 8 and the internal storage unit are initialized (step S1). However, at this point, the main power switch 16 for instructing the power supply to the entire recording / playback apparatus is in the OFF state. After completing the initial setting, the main control circuit 8 detects whether or not the main power switch 16 is turned on (step S2).

When it is detected that the main power switch 16 is in the ON state as a result of the detection, a switch (not shown) provided between the battery BAT and each circuit for supplying electric power to the entire recording / reproducing apparatus. Is turned on, and then the information of the index section 10A is read from the recording medium (memory section) 10 (step 3). That is, the operation start position information 10
A1, operation end position information 10A2, other code modes, operation conditions, etc. are read.

At this time, it is determined from the data read from the memory unit 10 whether the memory unit 10 has already recorded the index normally, that is, whether the format of the memory unit 10 is normal (step S4).

Here, when an unformatted memory unit 10 is inserted, it is determined that the memory unit 10 is not normal, and in that case, information indicating the usage condition is input to the index unit 10A of the memory unit 10. It is confirmed whether or not the memory format (initialization), which is the process of inputting "0" to the voice data section 10B, is performed (step S).
5). That is, the drive circuit 14 is controlled to cause the display 15 to display a confirmation display as to whether or not to perform the memory format.

If the button for confirming the memory format process (also used as the record button REC) is pressed, the memory section 10 is formatted (initialized) (step S6), and after this format is completed, the drive circuit is completed. 14
Is controlled to display the completion of initial setting on the display 15 (step S7).

When a button (also used as the stop button ST) for confirming that the memory is not formatted is pressed, the drive circuit 14 is controlled to display on the display 15 that the memory section 10 is not normal. An instruction display indicating that the memory unit 10 should be replaced is displayed, and a switch (not shown) provided between the battery BAT for supplying power to the entire recording / reproducing apparatus and each circuit is turned off (step S8). Thereafter, in order to replace the memory unit 10, the main power switch 16 is waited for being turned off (step S9), and when it is detected that it is turned off, the process returns to step S2.

On the other hand, in the case where the initial setting of the memory unit 10 is normally completed, the current operating position is detected from the information (operating position information 10A3) read from the index unit 10 after the initial setting completion display, and the drive circuit 14 is controlled to display the detected position on the display 15 (step S1).
0). After that, each circuit is placed in a waiting state while detecting which of the operation buttons of the device has been pressed (step S11).

When it is detected that any one of the operation buttons has been pressed, first, the operated button is the record button R.
If it is EC (step S12), and if the record button REC is pressed, the DSP unit 5 is controlled to compress the voice information input from the A / D converter 4, and the address control circuit 9 is controlled. Then, a recording process for recording in the voice data section 10B of the memory section 10 is started (step S13).

When the operated button is not the record button REC, the play button PL is detected (step S).
14). If the play button PL is pressed here,
The address control circuit 9 is controlled to read the recorded data from the voice data section 10B of the memory section 10,
The data is sent to the P section 5 for decompression processing, and the reproduction processing for sending audio information to the D / A converter 11 is started (step S15).

When the play button PL is not pressed, whether or not the fast-forward button FF is pressed is detected (step S16). If the fast-forward button FF has been pressed, the fast-forward process of sequentially fast-moving the operating position at an appropriate speed (for example, 20 times that at the time of reproduction) is started (step S17).

If the fast-forward button FF is not pressed,
Whether the return button REW is pressed or not is detected (step S18). If the return button REW is pressed, a return process for moving the operation position at the same speed in the opposite direction to the case of the fast-forwarding is started (step S1).
9).

Steps S13, S15, S17, S
When the stop button ST is pressed, each process of 19 exits each process and returns to step S11. If the operated button is not a button for recording, reproducing, fast-forwarding, returning, etc., the power is turned off or the state of various setting buttons is detected (step S20). Main power switch 16 is power supply OF
When the F operation is performed, the address control circuit 9 is controlled to
The information in the index unit 10A of the memory unit 10 is erased, and the index information stored in the unillustrated storage unit inside the main control unit 8 is replaced with the index unit 10A of the memory unit 10.
(Step S21). When this index transfer process is completed, the power switch (not shown) for supplying power to the entire apparatus, that is, each circuit is turned off (step S22). Then, the process returns to step S2.

When it is determined in step S20 that the main power switch 16 is not OFF, the state of the setting button is detected, the state is stored in the internal storage section, and the process returns to step S11. Here, the setting button is not the button actually provided in the device, but the record button REC, the play button PL, and the stop button S.
It is a button that is substituted by simultaneous pressing of some of T, fast-forward button FF, return button REW, I-mark button I, E-mark button E, and voice activation button VAD.

Next, the recording process in step S13 will be described in more detail with reference to the flowchart of FIG. When it is detected that the record button REC is pressed, the process shifts to this recording process, and first, a voice recording condition at that time (for example, voice activation, silence compression, use of variable rate type, etc.) is detected (step S31).
Depending on the detected condition, the voice recording condition mode is set to D.
Send to the SP unit 5 (step S32). Then, the recording start position in the voice data section 10B of the memory section 10 is obtained from the index information (motion position information) stored in the internal storage section, and information indicating the start position is stored in the index section 10A as the operation start position information 10A1. (Step S33). Here, the recording data is transferred from the DSP unit 5 (step S34), and the DSP unit 5
Encodes a voice signal and outputs encoded data (including voiced sound, unvoiced sound, and unvoiced determination code).

The main control circuit 8 determines whether or not the encoded data is to be processed in the silent compression mode (step S3).
5). For example, the silent compression mode is set, and the DSP unit 5
If the data sent from the device includes data indicating silence, the process jumps to step S39. Also,
If the data includes voiced or unvoiced sound data, that is, if there is no sound, an LED (not shown) provided in the display unit 15 is turned on to display that voice is input.

Then, the address at which the data-transferred compressed data should be written is calculated from the operating position information stored in the internal storage unit and output to the address control circuit 9 (step S36). At the same time, the compressed data transferred from the DSP section 5 is sent to the memory section 10 (step S37) and recorded in the audio data section 10B under the control of the address control circuit 9. Next, the operating position information stored in the internal storage unit is updated, and the updated value is set to the updated end position information 10A of the index unit 10A.
2 and the operating position information 10A3 are updated (step S3
8).

Then, it is detected whether the stop button ST is pressed (step S39), and if not pressed, the process jumps to step S34. Also, the stop button ST
If is pressed, the end position is determined and the recording process is exited.

Next, a voiced sound, an unvoiced sound, and a silent sound detection process in such a recording process will be described. During the recording process, the DSP unit 5 uses a CELP (Code Excited LPC) coding (analysis-synthesis type coding) system to code audio data. This CELP method
This is a method for extremely highly efficiently vector quantizing a sound source signal of an LPC (Linear Prediction Coefficients) synthesis filter using a codebook composed of various waveform patterns. As the residual signal, the difference between the predicted waveform pattern extracted by this method and the audio signal in the predetermined section,
The cross-correlation between this residual signal and the voice signal within the predetermined section is taken,
When this is divided by the autocorrelation of the audio signal, it is voiced when it is 0.81 or less, and it is unvoiced when it exceeds 0.81. Silence and unvoiced sound are determined by the level of autocorrelation of the voice signal. In other words, the residual signal is originally close to a signal (white noise) generated by random numbers, and if it has a correlation with this residual signal, it means that it is close to white noise. Can be determined. The autocorrelation can represent the energy waveform of the voice, and the relationship between the voice waveform and the energy waveform is as shown in FIG. Among them, when the noise energy and the noise level are discriminated by the above-mentioned method by the voice energy, the human language pattern (voice pattern) may include unvoiced sound close to noise. Therefore, in order not to exclude this unvoiced sound portion, unvoiced sound sections (t1, t2, t3) are set before and after the voiced sound.

As shown in FIG. 6, the DSP unit 5 determines such voiced sound, unvoiced sound, and silent sound simultaneously with the encoding process. That is, first, audio data is input from the A / D conversion circuit 4 and a frame (data sampled during 20 ms is defined as one frame) processing is performed (step S4).
1). Next, pre-emphasis and a Hamming windowing process are performed on the sampled data (step S4).
2). Then, the analysis-synthesis type encoding process as described above is performed (step S43). By this processing, the energy (autocorrelation) of the voice of the (current) frame and the cross-correlation with the residual waveform are obtained (step S44). At this time, the voiced sound is determined from the voice energy by the above-described method (step S45). If it is determined that the voiced sound is present, it is determined whether or not there is silence going back to the preceding frame or a plurality of predetermined preceding frames. (Step S46). If the previous frame or the predetermined plurality of previous frames is silent, the previous frame or the predetermined plurality of previous frames to the current frame are unvoiced frames (step S4).
7). After adding a code (voiced sound flag) indicating voiced sound to the current frame (step S48),
Get out of this process.

If it is determined in step S46 that the previous frame or the predetermined plurality of previous frames are not silent, the process jumps to step S48. On the other hand, when it is determined in step S45 that the current frame is not voiced sound, it is determined whether or not the previous frame is silent (step S49). If it is determined that the previous frame is not silent, it is determined whether the previous frame is voiced sound (step S50). When it is determined that the previous frame is a voiced sound, "5" is set to the internal counter n that counts the number of frames (step S51). Then, a code indicating unvoiced sound (unvoiced sound flag) is added to the voice coded data (step S52), and this processing is exited.

If it is determined in step S60 that the preceding frame is not a voiced sound, the value of the frame number counter n is decremented by "1" to count down (step S53). Then, it is judged whether or not the value of the counter n is smaller than zero (step S5).
4) If it is smaller, a code indicating silence (silence flag) is added to the voice coded data (step S55), and then the process is exited.

On the other hand, if it is determined in step S49 that the previous frame is silent, a code indicating that the current frame is silent is added to the voice coded data (step S56). Get out of this process.

As described above, the voiced sound and the unvoiced sound are distinguished from each other, and the code indicating them is added to the voice coded data. Next, the reproduction process in step S15 will be described in detail with reference to the flowchart in FIG.

When it is detected that the reproduction button PL has been pressed, the processing shifts to this reproduction processing, and the main control circuit 8 first detects the condition of voice reproduction at that time (silent compression, speed reproduction, noise removal, etc.). At the same time, the internal counter for counting the number of read blocks is reset (step S61). According to the detected condition, the condition mode of voice reproduction is sent to the DSP unit 5 (step S62).
Then, the read position of the audio data section 10B of the memory section 10 is obtained from the operation position information of the index information section 10A, and the drive circuit 14 is controlled to display the position on the display section 15 (step S63). Then, in order to read the voice message file from the voice data section 10B of the memory section 10, the address calculated from the operation start position information stored in the internal storage section is output to the address control circuit 9 (step S64). As a result, one block of data (for example, from the audio data unit 10B of the memory unit 10)
Data obtained by dividing the voice into blocks of 20 ms) is read by the main control circuit 8 (step S65).

Here, it is determined whether or not the fast-listening process is performed by detecting the mode set by the state of the voice activation button VAD (step S66). When performing fast listening, another block of data is added to the memory unit 10.
Is read from the main control circuit 8 (step S67). Then, it is determined whether or not there is an unvoiced sound flag in these two block data (step S68), and if there is an unvoiced sound flag, data transfer processing is performed to the DSP unit 5 (step S6).
9). If there is no unvoiced sound flag, an instruction to perform time axis compression is output to the DSP unit 5 (step S70), and D
Data is transferred to the SP unit 5 (step S69). The time base compression at this time uses the TDHS method as described above.

Then, the main control circuit 8 updates the reproduction position (operating position) information stored in the internal storage unit and also updates the operating position information 10A3 of the index unit 10A (step S71). Then, it is detected whether or not the stop button ST is pressed (step S72). If it is pressed, the reproduction processing is exited, but if it is not pressed, the processing returns to step S64 and the reproduction processing is continued.

When the above-described fast-listening reproduction processing is performed, the unvoiced waveform portion, that is, the consonant portion, is added and averaged (TDH).
Even if the fast listening process is performed without performing (S processing), it is possible to make it easier to hear.

In step S66, whether or not the fast-listening process is to be performed is determined by the voice activation button VAD before starting the reproduction of some modes as shown in the table of FIG. 5B. By making a selection, a priority condition is added to make a determination.

As described above, in the present embodiment, the cross-correlation between the voice signal within a predetermined time (for example, 20 ms) and the residual of the prediction signal derived by digital processing is calculated, and the calculated value and the voice are calculated. Voiced sound, unvoiced sound, and silence are determined by taking the ratio with the autocorrelation value of the signal. As a result, the time axis compression is performed by performing the TDHS method or partial thinning in the case of voiced sound or silence, and in the unvoiced section, time axis compression is not performed or the time axis compression ratio is reduced. In general, unvoiced parts are harder to hear than voiced sounds, so the above method makes them easier to hear. Further, within a certain time, for example, within about 4 seconds, the time axis compression is performed by prioritizing the silent part, the voiced sound part, and the unvoiced sound part in this order.

In the above embodiment, the voiced sound, the unvoiced sound, and the unvoiced sound are discriminated from each other at the time of recording the voice information, but the voice information is read out from the memory unit 10 at the time of reproduction to be detected by calculation. You can also Therefore, it is possible to distinguish between recording and reproducing.

[0054]

As described in detail above, according to the audio reproducing apparatus of the present invention, the digital audio signals that are successively reproduced are
When determining whether a voiced sound, unvoiced sound, or unvoiced sound is played back, and when the audio signal is played back faster than normal Does not compress the time axis for voice signals that are determined to be related to unvoiced sound that is generally harder to hear than voiced sound, or does not compress the time axis. Since the time axis compression is performed at a compression rate lower than the axis compression rate, the unvoiced part does not become difficult to hear even when performing high-speed reproduction of about double speed or more, and as a result, the entire reproduced sound is reproduced. It is possible to prevent people from hearing.

Further, in the voice recording apparatus according to the present invention, when the voice signal is digitized and sequentially recorded on a predetermined recording medium, the voice signal is related to voiced sound, unvoiced sound, and silent sound. Since it is detected that the information is detected and the detected information is recorded in the recording medium in association with the audio signal, the information recorded in association with the audio signal is reproduced from the information recorded at the time of reproduction in the audio reproduction device or the like. It becomes possible to easily determine whether the voice signal is related to voiced sound, unvoiced sound, or unvoiced sound.

Further, in another audio reproducing apparatus according to the present invention, it is determined whether the digital audio signals which are successively reproduced are related to voiced sound, unvoiced sound or unvoiced sound, and the audio signal is normally reproduced. When playing faster than
For voice signals that are determined to be related to voiced sound, the time axis is compressed.For voice signals that are determined to be related to unvoiced sound, which is generally harder to hear than voiced sound, Since the time axis is compressed, unnaturalness of voiced sound, unvoiced sound, and connection of silent sounds is eliminated, and the audibility of the sound during high-speed reproduction is improved.

In still another audio reproducing apparatus according to the present invention, it is determined whether the sequentially reproduced digital audio signal relates to voiced sound, unvoiced sound, or unvoiced sound, and outputs the audio signal. When playing at a higher speed than normal, the time axis is compressed for voice signals that are determined to be related to voiced sound, and data thinning processing is performed for voice signals that are determined to be related to silence. Therefore, while maintaining the intelligibility of the voice, that is,
Information can be heard in a short time while maintaining an easy-to-understand condition.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an audio recording / reproducing apparatus as an embodiment of the present invention.

FIG. 2 is a diagram showing a recording configuration of a memory unit.

FIG. 3 is an operation flowchart of a main control circuit.

4 is an operation flowchart for explaining details of a recording process in the flowchart of FIG.

5A is a diagram showing a relationship between a voice waveform and an energy waveform, and FIG. 5B is a table showing priority conditions for compressing silence, unvoiced sound, and voiced sound in each mode.

FIG. 6 is a flowchart of encoding processing in a DSP and determination processing of voiced sound and unvoiced sound.

7 is an operation flowchart for explaining details of a reproduction process in the flowchart of FIG.

FIG. 8 is a diagram for explaining a time axis compression process of the TDHS method.

[Explanation of symbols]

1 ... Microphone, 2, 12 ... Amplifier (AMP), 3 ...
Low-pass filter (LPF), 4 ... Analog / digital (A / D) converter, 5 ... Digital signal processing (DS)
P) section, 6 ... Control circuit, 7 ... Data input / output (I / O) buffer, 8 ... Main control circuit, 9 ... Address control circuit, 10
... recording medium (semiconductor memory section), 10A ... index section, 10A1 ... operation start position information, 10A2 ... operation end position information, 10A3 ... operation position information, 10B ... voice data section, 10B1, 10B2, 10B3 ... voice message file, 11 ... Digital / analog (D / A) converter, 13 ... Speaker, 14 ... Driving circuit, 15 ... Display,
16 ... Main power switch, REC ... Record button, PL ... Play button, ST ... Stop button, FF ... Fast forward button, R
EW ... Return button, I ... I mark button, E ... E mark button, VAD ... Voice activation (voice active detector) button.

[Procedure amendment]

[Submission date] May 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

5A is a diagram showing a relationship between a voice waveform and an energy waveform, and FIG. 5B is a chart showing a priority condition for performing compression of silence, unvoiced sound, and voiced sound in each mode.

Claims (4)

[Claims] 1. An audio reproduction unit for reproducing a digital audio signal, and determines whether the audio signals successively reproduced by the audio reproduction unit are related to voiced sound, unvoiced sound, or unvoiced sound. When the audio signal is reproduced at a higher speed than usual, the audio signal, which is determined to be related to voiced sound and unvoiced sound, is related to unvoiced sound by compressing the time axis. A time axis compression unit that does not compress the time axis of the determined audio signal or performs time axis compression at a compression rate lower than the time axis compression rate of the voiced and unvoiced audio signals. An audio reproducing device characterized by. 2. An audio recording means for digitizing and recording an audio signal on a predetermined recording medium, and an audio signal successively recorded by said audio recording means,
Detecting means for detecting whether it is related to voiced sound, unvoiced sound, or unvoiced sound, and the information detected by the detecting means, related information to be recorded in the recording medium in association with the audio signal. A voice recording device comprising: a recording unit. 3. A sound reproducing means for reproducing a digital sound signal, and determining whether the sound signals successively reproduced by the sound reproducing means are related to voiced sound, unvoiced sound or unvoiced sound. When the audio signal is reproduced at a higher speed than usual, the audio signal which is determined to be related to voiced sound by the determining means compresses the time axis and is determined to be related to unvoiced sound. And a conditional time axis compression means for performing time axis compression on the audio signal according to a predetermined condition. 4. A voice reproducing means for reproducing a digital voice signal, and determining whether the voice signals successively reproduced by the voice reproducing means relate to voiced sound, unvoiced sound or unvoiced sound. When the audio signal is reproduced at a higher speed than usual, the audio signal, which is determined to be related to voiced sound, is compressed by the determining means and is determined to be related to silence. And a data processing unit that performs data thinning processing on the audio signal.