JPH1027000A - Speech speed converter - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To make it possible to freely change the reproduction speed without providing a large dedicated memory. SOLUTION: A memory 10 for storing analog sound as digital sound data, a transfer speed control unit 20 for transferring a transfer speed of sound data read from the memory 10 at a variable speed in response to a switch operation of a down switch 2 or an up switch 3. With down switch 2
Alternatively, a compression / expansion rate control circuit 31 for calculating a compression rate or an expansion rate according to the operation of the up switch 3
And a speech speed conversion unit 30 comprising a compression / expansion circuit 31 for compressing or expanding audio data transferred from the transfer speed control unit 20 based on the compression ratio or expansion ratio calculated by the compression / expansion ratio control circuit 31. I have.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speech speed converter for compressing or expanding voice data stored in a memory in accordance with a setting operation from a setting means and reproducing the voice data at a variable speed.

[0002]

2. Description of the Related Art In recent years, analog audio input from a microphone or the like is converted into digital audio data and recorded on a recording medium such as a memory, and the recorded digital audio data is converted into an analog audio signal and can be reproduced by a speaker. The audio reproduction device described above is applied to various electronic and communication devices such as telephones, and is used as a voice memo and voice guidance.

There have been proposed various types of audio reproducing apparatuses of this kind, which can reproduce digital audio data recorded on a recording medium such as a memory in a compressed manner so as to be able to play at a high speed at a high speed. For example, in Japanese Patent Application Laid-Open No. Hei 6-332500, when the playback speed specified by the operation unit is between a standard playback speed and a predetermined high-speed playback speed, the content of the audio signal is recognized by performing time axis compression. It has been proposed to reproduce in a state where it can be performed, and when the speed exceeds a predetermined high-speed reproduction speed, it is possible to determine whether an audio signal is recorded or not.

Here, the time axis compression described in the above-mentioned Japanese Patent Application Laid-Open No. 6-332500, for example, in double-speed reproduction, as shown in FIG.
Is multiplied by the weight window function W (m) and the rear part P2 is multiplied by the opposite weight window function 1-W (m). A TDHS (Time Domain Harmonic Scale) method for axial compression is adopted. That is, by taking the average of the two waveforms while maintaining the anteroposterior relationship, the compression is performed so that the sounds can be connected and heard.

In quadruple speed reproduction, FIG.
As shown in the figure, the weight window function W
(M), the rear part P6 is multiplied by the opposite weight window function 1-W (m), and the two waveform parts between the waveform parts P5 and P6 are thinned to obtain a weighted waveform P5. By adding the section and the P6 section, the signal for four cycles is time-axis compressed to one cycle. Further, as shown by arrows in FIGS. 5A and 5B, by changing the slope of the weight window function, finer speed adjustment can be performed.

[0006]

However, in the device described in Japanese Patent Application Laid-Open No. Hei 6-332500, the transfer rate of audio data read from the memory cannot be controlled, so that a large-capacity dedicated memory must be provided. This raises the problem of increased costs. Also,
Since the compression rate of the audio data cannot be controlled continuously, that is, the reproduction speed cannot be controlled continuously, there arises a problem that the operability of this type of reproduction apparatus is poor. In view of the above, the present invention has been made in view of the above problems, and has as its object to enable the reproduction speed to be freely variable without providing a large dedicated memory.

[0007]

According to the present invention, there is provided a speech speed converter for compressing or expanding voice data stored in a memory in accordance with a setting operation from a setting means to reproduce the voice data at a variable speed. According to the invention described in (1), by providing the transfer rate control means for performing variable-speed transfer of the transfer rate of the audio data read from the memory in accordance with the setting operation from the setting means, it is possible to provide a desired memory only by providing a small-capacity memory. Since voice data can be compressed and decompressed, it is not necessary to provide a large-capacity memory, and this type of speech speed conversion device can be manufactured at low cost.

Further, by providing a compression / expansion rate control means for calculating a compression rate or an expansion rate according to a setting operation from the setting means, it is possible to continuously calculate a compression rate or an expansion rate. Continuously compress audio data,
It can be extended. Furthermore, by providing compression / expansion means for compressing or expanding audio data transferred from the transfer rate control means based on the compression rate or expansion rate calculated by the compression / expansion rate control means, audio data can be efficiently compressed and expanded. Become like

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention applied to a voice memo or voice guidance of a cellular phone. FIG. 1 is a diagram schematically showing a mobile phone 1 having a voice memo or voice guidance function. The mobile phone 1 includes a down switch 2 for gradually and slowly reproducing voice data stored in a voice memo or a voice guidance, an up switch 3 for gradually and rapidly reproducing the voice data, and setting of operation of these switches 2 and 3. Reset switch 4, and dial key 5 consisting of 12 keys of ten keys, asterisk key (*) and sharp key (#) for dialing
And a display device 6 for displaying a dial number or the like on its outer surface, and a speech speed conversion device of the present invention connected to the down switch 2, the up switch 3 and the reset switch 4 therein (see FIG. 2). It has.

FIG. 2 is a block diagram showing the configuration of the speech speed converter of the present invention. This speech speed conversion device encodes and stores an analog voice signal into digital voice data and stores a digital voice data read out from the memory 10 in accordance with a switch operation of the down switch 2 and a switch operation of the up switch 3. A transfer rate control unit 20 for transferring to the speech speed conversion unit 30 at a speed determined by the user, calculating a decompression rate according to the switch operation of the down switch 2 or a compression rate according to the switch operation of the up switch 3, and calculating the calculated decompression rate. Alternatively, a speech speed conversion unit 30 for expanding or compressing digital voice data based on a compression ratio.
A D / A converter 40 for converting digital voice data output from the speech speed converter 30 after being expanded or compressed into an analog voice signal, and converting the converted analog voice signal into voice; Each switch 2,
3 and 4.

Here, each of the switches 2, 3, and 4 serves as setting means, and the down switch 2 outputs a descending signal every predetermined time until the switch 2 reaches a predetermined value while the switch 2 is pressed. This is a switch for holding the output at the stopped position by stopping the pressing. On the other hand, up switch 3
Is a switch that outputs an ascending signal at predetermined time intervals until a predetermined value is reached while the switch 3 is being pressed, and holds the output at the stopped position by stopping the pressing.

The memory 10 is composed of a ROM or a RAM, and digital voice data obtained by encoding analog voice as it is in a digital modulation system or analog voice is converted into an adaptive differential pulse code modulation system (Adaptive D-code).
iferential Pulse Cord Modulation), so-called ADP
Digital audio data encoded by CM is stored in advance. The memory 10 has a storage capacity of 10 Mbits for storing digital audio data for 5 minutes, for example.

The transfer rate control unit 20 converts the digital audio data stored in the memory 10 into one frame (in this case, 3
The digital audio data of 2 ms is defined as one frame) from the memory 10 and the speed at which the read digital audio data of each frame is transferred to the speech speed conversion unit 30 is controlled by the switch operation of the down switch 2 described above. Alternatively, it is provided for controlling according to the switch operation of the up switch 3. Then, the digital audio data for each frame is read out from the memory 10 at a speed corresponding to the expansion rate or the compression rate (hereinafter, referred to as the compression / expansion rate) calculated by the compression / expansion rate control circuit 31 of the speech speed conversion section 30 described later. The digital audio data for each frame is transmitted to the memory (for example, RAM) of the speech speed conversion unit 30 at the transfer speed corresponding to the compression / decompression rate. Therefore, the storage capacity of the memory (for example, RAM) of the speech speed conversion unit 30 is small, and for example, a storage capacity of 10 to 20 K bits is used.

The speech speed conversion unit 30 includes a CPU, a ROM, and a RAM.
The microcomputer calculates and calculates a decompression rate according to a switch operation of the down switch 2 or a compression rate according to a switch operation of the up switch 3 and transfers the calculated result to a transfer speed. The compression / expansion rate control circuit 31 sent to the control unit 20 and the compression / expansion circuit 32 and the digital audio data stored in the memory 10 are fetched into the RAM via the transfer rate control unit 20 for each frame, and are stored in the RAM. The captured digital audio data for each frame is compressed or decompressed based on the compression / decompression rate sent from the compression / decompression rate control circuit 31, and the compressed or decompressed digital audio data is sent to the D / A conversion unit 40. And a compression / decompression circuit 32.

The D / A converter 40 compresses or expands the compressed or expanded one sent from the compression / expansion circuit 32 of the speech speed converter 30.
A D / A converter for converting digital audio data for each frame into an analog audio signal, an amplifier for amplifying the analog audio signal converted by the D / A converter, and converting the analog audio signal amplified by the amplifier to audio Speaker.

Next, the processing operation of the speech speed converter constructed as described above will be described with reference to the flowcharts of FIGS. It should be noted that a program corresponding to this flowchart is stored in advance in a ROM of a microcomputer constituting the speech speed conversion unit 30. When a power switch (not shown) of the mobile phone 1 is turned on,
The microcomputer of the speech speed conversion unit 30 performs step 10
At 0, the execution of the speech speed conversion processing program is started. Next, in step 102, the count value m of the first frame counter is reset (m = 0), and then in step 10
4, the count value k of the second frame counter is reset (k = 0), and the compression / expansion rate R (m)
Is initialized to an initial value Ri (Ri = 1.0).

Next, the process proceeds to step 106, where the transfer rate control circuit 20 transfers one frame (32 ms) of the digital audio data stored in the memory 10 to the transfer rate corresponding to the compression / decompression rate of the compression / decompression rate control circuit 31. (For example, when the up switch 3 is pressed and compressed, the data is transferred at a high speed, and when the down switch 2 is pressed and expanded, the data is transferred at a low speed.) Digital audio data S (m, n) ( Note that n can be set to a numerical value from 1 to N, and N represents a sampling value, which is set to, for example, 256), and increments the count value m of the first frame counter reset in step 102. (M = m + 1).

Next, the routine proceeds to step 108, where it is determined whether or not one of the switches 2, 3, and 4 among the down switch 2, the up switch 3, and the reset switch 4 has been operated. Here, if any one of the switches 2, 3, and 4 is operated, the operation signal is input to the speech speed conversion unit 30 and the operation of this step 1 is performed.
At 08, “Yes” is determined, and the routine goes to the next step 110. If no switch operation has been performed on any of the switches 2, 3, and 4, "No" is determined in step 108, and the process proceeds to step 120.

At step 110, step 1
In step 1, the count value k of the second frame counter reset in step 04 is incremented (k = k + 1).
Then, the process proceeds to step 12, where it is determined whether or not the switch operation determined in step 108 is the switch operation of the reset switch 4. If the reset switch 4 has been operated, "Yes" is determined in step 112, and the process returns to step 104 to repeatedly execute the above-described processing operation. If the reset switch 4 has not been operated, the determination in step 112 is “No”, and the process proceeds to step 114.

At step 114, step 1
It is determined whether or not the switch operation determined at 08 is the switch operation of the up switch 3. If the up switch 3 is operated, this step 114
Is determined to be "Yes", and the process proceeds to step 116. If the up switch 3 has not been operated, the down switch 2 has been operated. Then, the process proceeds to step 118.

Since the up switch 3 outputs an ascending signal at predetermined time intervals until the value reaches a predetermined value while the switch 3 is being pressed, the operation of the up switch 3 is switched to step 116. That is, the compression / decompression ratio (compression ratio in this case) R (m) = Ff (R (m-1), k) according to the operation of increasing the compression ratio.
That is, when the compression / expansion rate control unit detects the switch operation state of the up switch 3, the compression rate R (m) = Ff (R (m-1), k) is calculated based on a signal corresponding to the detected value. The compression ratio R (m) is calculated based on the following equation (1), and the process proceeds to the next step 120.

[0022]

## EQU00001 ## R (m) = Re + (Ri-Re) exp (-m / .tau.) Where Re represents the final compression / expansion rate and .tau. Represents time.

Similarly, the down switch 2 outputs a descending signal every predetermined time until it reaches a predetermined value while the switch 2 is being pressed.
At 18, the switch operation of the down switch 2 is performed.
That is, the compression / expansion rate (extension rate in this case) R (m) = Fs (R (m−1), k) is changed according to the operation of increasing the expansion rate. That is, when the compression / expansion rate control circuit 31 detects the switch operation state of the down switch 2, the expansion rate R (m) = Fs (R (m−
The operations of 1) and k) are performed on the basis of the above equation (1) to calculate the elongation rate R (m), and the process proceeds to the next step 120.

At step 120, step 1
The compression ratio R (m) obtained in step 16 or step 118
Step 106 based on the elongation rate R (m) obtained in
The one-frame audio waveform data S (m,
n) is subjected to time axis compression or time axis expansion, and the process proceeds to the next step 122 as new audio waveform data S ′ (m, n (n = 1 to N−α)).

At step 122, step 1
The new voice waveform data S ′ (m, n (n
= 1−N−α)) in the RAM,
New audio waveform data S ′ (m, n (n = 1 to N−
α)) to the D / A converter 40. This gives D
The D / A converter of the / A converter 40 converts the new audio waveform data S ′ (m, n (n = 1 to N−α)) into an analog audio signal and is converted by the D / A converter. The amplified analog audio signal is amplified by an amplifier, and a compressed or expanded audio is emitted from a speaker.

Then, proceeding to step 124, the speech speed conversion unit 30 determines whether or not the transfer speed control unit 20 has read all of the digital voice data stored in the memory 10.
That is, it is determined whether or not data to be read by the transfer speed control unit 20 remains or whether or not a reproduction end switch (not shown) has been pressed. If digital audio data to be read by the transfer rate control unit 20 remains, or if the reproduction end switch has not been pressed, "Yes" is determined in step 124 and the process returns to step 106, where the audio waveform data And the processing operations from step 106 to step 124 are repeatedly executed. If there is no data left to be read by the transfer rate control unit 20 or if the reproduction end switch is pressed, it is determined that the audio reproduction process has been completed, and the process proceeds to step 126 to terminate the execution of this processing program.

In the present embodiment configured as described above, the digital audio data stored in the memory 10 is converted into an expansion rate according to the operation of the down switch 2 or a compression rate according to the operation of the up switch 3. Since the transfer speed control unit 20 that performs variable-speed transfer in response is provided, the speech speed conversion unit 30 can compress and decompress desired audio data only by providing a small-capacity memory (RAM) of 10 to 20 Kbits. This eliminates the need to provide a large-capacity memory, so that this type of speech speed converter can be manufactured at low cost.

Further, since a compression / decompression rate control circuit 31 for calculating a decompression rate in response to the operation of the switch of the down switch 2 or a compression rate in response to the operation of the switch of the up switch 3 is provided, the compression rate or the decompression is continuously increased. The rate can be calculated, and the digital audio data stored in the memory 10 can be continuously compressed and decompressed.

Furthermore, a compression / decompression circuit 32 for compressing or decompressing digital audio data stored in the memory 10 transferred from the transfer rate control unit 20 based on the compression / decompression rate calculated by the compression / decompression rate control circuit 31 is provided. Accordingly, audio data can be efficiently compressed and decompressed.

In the above embodiment, an example has been described in which the digital audio data stored in the memory 10 is expanded or compressed by using the down switch 2 and the up switch 3 as the setting means. Various sensors such as a vehicle speed sensor or a noise sensor may be used. For example, when a noise sensor is used, if the noise is loud, the sound may be expanded and reproduced at a low speed so that the sound can be clearly heard.

Also, in the above-described embodiment, an example in which the speech speed conversion device of the present invention is applied to a mobile phone having a voice memo or voice guidance function has been described.
The present invention is not limited to a mobile phone, and may be used for an electronic communication device having a voice memo or a voice guidance function, for example, a navigation system having a voice guidance function. When used in a navigation system having a voice guidance function, it is preferable to set so that when the vehicle speed increases, the voice is compressed and reproduced at a high speed, and when the vehicle speed is low, the voice is reproduced at a normal speed to follow the vehicle speed. With this setting, when the vehicle approaches the destination, voice guidance is performed at a rapid speed, and it is possible to prevent the vehicle from passing through the destination even when driving at a high speed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outer shape of a mobile phone when a speech speed conversion device of the present invention is applied to a mobile phone.

FIG. 2 is a block diagram illustrating a configuration of a speech speed conversion device according to the present invention.

FIG. 3 is a diagram illustrating a first half of a flowchart illustrating a processing operation of the speech speed conversion device in FIG. 2;

FIG. 4 is a diagram illustrating a latter half of a flowchart illustrating a processing operation of the speech speed conversion device in FIG. 2;

FIG. 5 is a waveform chart showing conventional time axis compression of audio.

[Explanation of symbols]

1 ... mobile phone, 2 ... down switch (setting means), 3 ...
Up switch (setting means), 4 ... Reset switch,
DESCRIPTION OF SYMBOLS 10 ... Memory, 20 ... Transfer rate control part, 30 ... Speech rate conversion part, 31 ... Compression / decompression rate control circuit, 32 ... Compression / decompression circuit,
40 D / A converter

Claims (1)

[Claims] 1. A speech speed converter for compressing or decompressing audio data stored in a memory in accordance with a setting operation from a setting means and reproducing the audio data at a variable speed, wherein the transfer speed of the audio data read from the memory is set to Transfer speed control means for performing variable speed transfer in accordance with a setting operation from a setting means; compression / expansion rate control means for calculating a compression rate or an expansion rate in accordance with the setting operation from the setting means; and the compression / expansion rate control means And a compression / expansion means for compressing or decompressing the audio data transferred from the transfer rate control means based on the compression rate or the decompression rate calculated by the above.