JPH0798937A - Voice recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the reduction of power consumption that is a significant factor for a portable application requiring a battery power source as suppressing cost increment. CONSTITUTION:A data compression circuit 4 which stores by compressing digitized input voice data and reproduced voice data when they are stored transiently in buffer memory 6, respectively, and a data restoration circuit 7 which restores compression data read out of the buffer memory 6 to original voice data are provided. Thus, it is possible to extend the period of intermittent recording of data on a magneto-optical disk 10 without increasing memory capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts an analog audio signal obtained by a microphone or the like into a digital signal and records it on a magneto-optical disk or the like, and at the time of reproduction, a digital signal recorded on the magneto-optical disk or the like. The present invention relates to a voice recording / reproducing apparatus such as a dictation recorder that converts a voice into an analog voice signal and outputs the analog voice signal through a speaker or the like.

[0002]

2. Description of the Related Art Conventionally, a cassette tape recorder using a magnetic tape such as a cassette tape has been generally known as a device for recording and reproducing voice. The device using this magnetic tape has the advantages that the tape itself is inexpensive and that recording and reproduction can be performed for a long time, but has the disadvantage that it takes time to access such as fast forward and rewind.

On the other hand, in recent years, a voice recording / reproducing apparatus using a disk such as a magneto-optical disk instead of a magnetic tape has been developed. In this way, the audio recording / reproducing apparatus using a disk as a recording medium has an access speed usually on the order of 1 second or less, and it is possible to find the beginning of the audio almost instantaneously. It is a very convenient recorder.

A voice recording / reproducing apparatus using a magneto-optical disc as a recording medium as described above usually has an A / A function for converting an analog voice signal input through a microphone or the like into a digital signal.
A D converter and a memory (generally a semiconductor memory is used) for temporarily storing the converted digital signal are provided and configured. When an audio signal is recorded on a disc with such a configuration, generally, the speed of reading from the memory and writing to the disc is faster than the speed of inputting the audio data to the memory. When the memory becomes almost full, writing to the disk is started sequentially.

FIG. 4 is a chart showing the timing of writing and reading to and from the memory when the audio signal is recorded on the disk as described above. In FIG. 4, the vertical axis shows the memory address and the horizontal axis shows the passage of time. Is shown. A solid line A shows that the data input from the A / D converter to the memory is sequentially recorded from time 0 address, and a solid line B shows that the data in the memory is
It is shown that the addresses are sequentially read from the address 0 with time. The shaded portion between the solid line A and the solid line B indicates the effective data portion recorded in the memory.

When the voice data indicated by the solid line A is stored in the memory to some extent, the data reading starts from the time t1 as indicated by the solid line B, and is stopped at the time t2 when there is no valid data in the memory. . During this period (T1 period), the read data is recorded on the magneto-optical disk at almost the same timing. Then, in the next T2 period, an intermittent recording operation is performed such that recording is performed again on the magneto-optical disk.

FIG. 5 shows the elapsed time of the power consumption of the apparatus when the intermittent recording is repeated as described above. That is, at each recording time, t slightly before the time t1
In the run-up section T0 from the time point 1 ′ to the time point t1, the magneto-optical disk is pre-rotated and the tracking of the optical pickup is started.
With the servo circuit current for searching the recording position,
This results in a relatively large power consumption. Then, after passing through the approach section T0, a recording current is applied to the magnetic head in accordance with the signal read from the memory, and at the same time, laser light is emitted from the laser diode of the optical pickup, and audio to the magneto-optical disk is recorded. Data is recorded.

In the case of reproducing the data recorded on the disk, the data read from the disk is once stored in the memory and then converted into an analog signal through the D / A converter, and the speaker or the like is also reproduced. It is designed to output through.

[0009]

However, in the above-mentioned conventional audio recording / reproducing apparatus, for example, the starting current of the motor or the servo for searching the recording position is started every time the intermittent recording on the disk is started during recording. Since there is a relatively large power consumption due to the starting current, there is the problem that sufficient performance cannot be obtained when this is used, for example, as a dictation recorder.

That is, such a dictation recorder is often used in any place, and therefore, it is required to be portable and to be small and lightweight, and to have a structure in which a battery is used as a power source. Power saving for use is an essential requirement, and performance for such power saving is insufficient.

On the other hand, it is conceivable to increase the capacity of the memory for temporary storage in order to save power in the voice recording / reproducing apparatus as described above. As a result, the period for intermittently recording the data stored in the memory on the disk becomes longer, and the number of intermittent recordings is reduced, so that the power consumption is reduced. However, in such a configuration in which the memory capacity is increased, the semiconductor memory used in such a device is expensive, which causes a problem that the cost of the product is increased.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to enable power saving without increasing the memory capacity, and to provide a simpler configuration. An object is to provide an audio recording / playback device to obtain.

[0013]

In order to achieve the above object, a voice recording / reproducing apparatus according to claim 1 of the present invention digitizes an analog voice signal input during recording to generate input voice data. , This input audio data is once stored in the memory and then read out and recorded in a disk-shaped recording medium, while the reproduced audio data reproduced from the recording medium at the time of reproduction is temporarily stored in the memory and then read out,
In a voice recording / reproducing device for converting and outputting to an analog voice signal, a data compression means for compressing each voice data when storing the input voice data and the reproduced voice data in the memory, and each compressed data read from the memory. Data recovery means for restoring the original audio data by an operation reverse to the compression operation by the data compression means is provided.

According to a second aspect of the present invention, there is provided the audio recording / reproducing apparatus according to the first aspect, further comprising an auxiliary memory for temporarily storing compression information corresponding to the compression data by the compression means. The data decompression means is characterized by decompressing the audio data based on the compressed data and the compression information read from the memory and the auxiliary memory, respectively.

[0015]

In the voice recording / reproducing apparatus according to the first aspect, the analog signal input during recording is converted into digital voice data through the A / D converter or the like and temporarily stored in the memory. Since the data is compressed by the compression means, the data amount becomes smaller than the data amount after passing through the A / D converter. And
When this amount of data approaches the capacity of the memory, the compressed data is read from the memory, restored to the original audio data by the data decompression means, and recorded on the disc-shaped recording medium. At the time of reproduction, similarly to the above, the reproduced audio data reproduced from the recording medium is compressed in the memory after being subjected to data compression by the data compression means, and then converted into the compressed data read out from the memory. On the other hand, the data restoration means restores the original voice data, converts it into an analog voice signal, and outputs it.

As described above, in the above, since the data is compressed when the voice data is stored in the memory, the data amount when the memory capacity is full corresponds to a longer recording time than the conventional one. Become. Therefore, for example, at the time of recording, the frequency of recording on the recording medium decreases every time the amount of data stored in the memory becomes close to the memory capacity, which reduces the overall power consumption. As a result, power saving can be achieved without increasing the memory capacity.

In the voice recording / reproducing apparatus according to the second aspect of the invention, for example, when there is a silent period in the voice data at the time of recording, the data at the start point and the end point of the silent period are supplemented as compression information. Stored in memory.
At this time, the memory stores the data obtained by compressing the audio data corresponding to the input analog audio signal in the period excluding the silent period. Therefore, the amount of data when the memory capacity is full corresponds to a longer recording time than the conventional one. As a result, the frequency of recording on the recording medium can be further reduced, and the power consumption can be further reduced.

Further, in the configuration in which the compressed information as described above is stored in the same memory together with the compressed data, a peripheral circuit or the like for further converting the compressed information and the compressed data into a data structure capable of being discriminated is additionally required. However, in the above, since the compression information is stored in the auxiliary memory separately from the compressed data, the overall configuration can be simplified.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

First, referring to FIG. 1, the structure of the voice recording / reproducing apparatus of this embodiment will be described together with its operation. At the time of recording, voice is converted into an analog voice signal through the microphone 1, and this voice signal is amplified by the amplifier 2 and then A /
It is converted into a digital audio signal by the D converter 3. The digitized audio signal (hereinafter referred to as audio data) is then input to the data compression circuit (data compression means) 4 and compressed by a fraction of the data amount. In this case, the changeover switch SW shown in the drawing is changed over to the recording direction (R). The compression of digital data is performed by, for example, DM (Delta Modulati).
On) method or the like, which is generally well known.

Next, the compressed data is written in the buffer memory 6 which is, for example, a semiconductor memory through the memory controller 5. Memory controller 5
Writes data while sequentially incrementing from the address 0 of the buffer memory 6, and reads the data from the address 0 when the data in the buffer memory 6 is almost full, and a data restoration circuit (data restoration means) Output to 7. When the data restoration circuit 7 restores the original audio data, this audio data is encoded by the recording signal encoder 8 and then encoded by the magnetic head 9 as a magneto-optical disk 10 as a recording medium.
Information is recorded as magnetization reversal information on the portion of the surface of the laser irradiated with the laser light from the optical pickup 11.

During the recording of the audio data, the servo controller 13 controls the spindle motor 12 to rotate the magneto-optical disk 10 at a constant speed and controls the laser light from the optical pickup 11 to always trace the recording track. Work.

At the time of reproduction, the reproduction audio signal (magnetization reversal information) read from the magneto-optical disk 10 by the optical pickup 11 is restored to the audio data by the reproduction signal decoder 14, and the restored audio data is the changeover switch SW. Via the data compression circuit 4, the data is temporarily stored in the buffer memory 6 via the data compression circuit 4. At this time, the data compression circuit 4 and the buffer memory 6 / data decompression circuit 7 can be shared during recording by switching the changeover switch SW in the reproduction direction (P).

The data stored in the buffer memory 6 is
It is read out through the data restoration circuit 7. In order to reproduce the voice, it is necessary to read the data so that the data transfer speed becomes a constant speed. However, if the data is compressed in a variable length, it is impossible to control the read speed of the buffer memory 6, so A FIFO circuit 15 for adjusting the transfer timing is inserted.

Finally, the audio data output from the FIFO circuit 15 at fixed time intervals is converted into an analog audio signal by the D / A converter 16, amplified by the amplifier 17, and output from the speaker 18 as audio.

Further, in the above embodiment, the data compression circuit 4 performs more efficient compression by utilizing the characteristics of the audio signal, for example, the silence compression method often used in audio recording. First, when silence is detected in the data compression circuit 4, the length of the silence and the compression information indicating which address of the data recorded in the buffer memory 6 the silence period corresponds to are recorded in the auxiliary memory 19. Next, in the data restoration circuit 7, this auxiliary memory 19
The data from the buffer memory 6 is decompressed using the compression information from.

Next, the timing of writing and reading the compressed audio data to and from the buffer memory 6 in the above audio recording / reproducing apparatus will be described with reference to FIG.

In the figure, the vertical axis shows the address of the buffer memory 6, and the horizontal axis shows the passage of time. A solid line A shows how the data input from the data compression circuit 4 to the buffer memory 6 is sequentially recorded from address 0 with time, and a solid line B shows a recording signal encoder from the buffer memory 6 through the data decompression circuit 7. It is shown that the data output to 8 are sequentially read from address 0 with time. The shaded portion between the solid line A and the solid line B indicates the effective data portion recorded in the buffer memory 6.

In the present embodiment, since the audio data is compressed by the data compression circuit 4, the inclination of the solid line A becomes gentler by the amount of compression as compared with the inclination shown in FIG. Further, in the conventional device, as shown in FIG.
As shown in FIG. 2, the data is recorded in the memory at a constant rate.
As described above, the data is recorded while changing the inclination of the solid line A.

When the data indicated by the solid line A is stored in the buffer memory 6 to some extent, the data reading starts from the time point t5 as shown by the solid line B, and the valid data in the buffer memory 6 disappears at the time point t6. Will be stopped at. During this period (T3 period), the read data is encoded and recorded on the magneto-optical disk 10 at substantially the same timing. However, during this T3 period, the amount of data is large, so in the explanatory view of the conventional apparatus. Figure 4
Is longer than the T1 period and T2 period.

FIG. 3 shows the elapsed time of the power consumption of the apparatus at this time. Here, as in FIG. 5 which is an explanatory view of the conventional apparatus, as a preparation for starting recording on the magneto-optical disk 10 from the time point t5, the run-up time T0 is provided from the time point t5 ′, which is slightly before the time point t5, and during that period. Magneto-optical disk 10
Is rotated in advance, and tracking of the optical pickup 11 is performed. Therefore, when recording on the magneto-optical disk 10, the power is consumed by that amount.

Comparing FIG. 3 with FIG. 5 in the conventional apparatus, the time obtained by adding the T1 period and the T2 period is almost equal to the T3 period. If all the run-up periods are T0,
In the present embodiment shown in FIG. 3, it can be seen that the total power consumption is reduced by the period T0 as compared with the conventional example shown in FIG.

Although the data compression rate is about 1/2 in this example, the above-mentioned power reduction is further increased because the higher compression rate can be obtained relatively easily for voice data. Can be expected. The reason for this is that the compression / decompression of audio data can be performed by a relatively simple digital circuit or software of the memory controller 5, whereby a relative memory expansion effect of 2 to 4 times can be realized.

As described above, in this embodiment, the analog audio signal input during recording is converted into digital audio data through the A / D converter 3 and then compressed in the buffer memory 6 after data compression. Remembered,
Further, when the amount of data stored in the buffer memory 6 approaches the capacity of the buffer memory 6, the compressed data is read from the buffer memory 6 and restored by the data decompression circuit 7 to the original audio data. Magnetic disk 10
Recorded in.

As described above, in the above, since the data is compressed when the voice data is stored in the buffer memory 6, the data amount when the memory capacity becomes full corresponds to a longer recording time than the conventional one. Will be things. Therefore, for example, the frequency of recording on the recording medium is reduced each time the memory capacity is full during recording, so that power consumption is reduced during intermittent recording. As a result, without increasing the capacity of the buffer memory 6, with a simpler configuration,
Power saving can be achieved.

Further, in the above-described embodiment, the data compression circuit 4 and the data decompression circuit 7 for compressing and decompressing each data at the time of recording and at the time of reproduction can be shared by switching by the changeover switch SW. Since this is also the case, the overall configuration can be further simplified.

Further, in the above embodiment, when there is a silent period in the voice data at the time of recording, data indicating the starting point and the ending point of the silent period are stored in the auxiliary memory 19 as compression information. Since the buffer memory 6 stores the data obtained by compressing the audio data corresponding to the input analog audio signal during the period excluding the silent period, the data amount when the capacity of the buffer memory 6 becomes full is the conventional one. As a result, it is possible to correspond to a longer recording time, and as a result, it is possible to further reduce the frequency of recording on the recording medium, so that it is possible to further reduce power consumption.

Further, by providing the auxiliary memory 19 for recording the compressed information as described above separately from the buffer memory 6, compared with the case where the compressed information is stored together with the compressed audio data in the buffer memory 6. Thus, the peripheral circuit can be made simpler.

In the above embodiment, the data compressing circuit 4 and the data decompressing circuit 7 for compressing each data at the time of recording and reproducing and the data decompressing circuit 7 can be shared by switching with the changeover switch SW. However, the data compression circuit and the data decompression circuit may be separately provided for recording and reproduction.

[0040]

As described above, the audio recording / reproducing apparatus according to the first aspect of the present invention compresses each audio data when storing the digitized input audio data and the reproduced audio data in the memory. The data compression means and the data decompression means for returning each compressed data read from the memory to the original audio data by the operation reverse to the compression operation in the data compression means are provided.

As a result, it is possible to lengthen the intermittent recording cycle of the data on the recording medium without increasing the capacity of the memory, and to reduce the power consumption, which is an important requirement for portable applications requiring a battery power source. The effect is that reduction can be achieved while suppressing cost increase.

According to a second aspect of the present invention, there is further provided an auxiliary memory for temporarily storing compression information corresponding to the compressed data in the compression means, and the data decompression means is provided with a memory and an auxiliary memory. The audio data is decompressed on the basis of the compressed data and the compression information read from each of the above.

As a result, the frequency of recording on the recording medium can be further reduced, so that the power consumption can be further reduced and the overall structure can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an overall configuration of a voice recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a timing chart showing timings of writing and reading data to and from a buffer memory in the above device.

FIG. 3 is an explanatory diagram showing an example of a temporal change in power consumption in the device.

FIG. 4 is a timing chart showing timings of writing and reading data to and from a buffer memory in a conventional audio recording / playback apparatus.

5 is an explanatory diagram showing an example of a change over time in power consumption in the conventional device shown in FIG.

[Explanation of symbols]

 3 A / D converter 4 Data compression circuit (data compression means) 5 Memory controller 6 Buffer memory 7 Data restoration circuit (data restoration means) 9 Magnetic head 10 Magneto-optical disk (recording medium) 11 Optical pickup 16 D / A converter 19 Auxiliary memory

Claims (2)

[Claims] 1. An analog audio signal input at the time of recording is digitized to generate input audio data, the input audio data is temporarily stored in a memory, then read out, and recorded on a disk-shaped recording medium, while being reproduced. In an audio recording / reproducing apparatus for reproducing audio data which is sometimes reproduced from a recording medium, temporarily storing it in a memory and then reading it out, converting it into an analog audio signal and outputting it, the input audio data and the reproduced audio data are respectively stored in the memory. At this time, there are provided data compression means for compressing each audio data and data decompression means for returning each compressed data read from the memory to the original audio data by an operation reverse to the compression operation by the data compression means. A voice recording / playback device characterized in that 2. An auxiliary memory for temporarily storing compression information corresponding to the compressed data in the compression means is further provided, and the data decompression means is compressed data and compression information read from the memory and the auxiliary memory, respectively. The voice recording / reproducing apparatus according to claim 1, wherein the voice data is restored based on the above.