JPH0372721A - Method and device for recording and reproducing - Google Patents

Abstract

PURPOSE:To reduce the quantity of stored information and to follow a waveform whose amplitude is quickly changed by converting an original audio signal to a digital audio signal in a specific conversion range to record and converting the digital audio signal to an analog audio signal in a prescribed conversion range to reproduce the signal. CONSTITUTION:A first converting means TR1 converts an original audio signal a into a digital audio signal b1 in the conversion range selected in accordance with the amplitude of the original audio signal a by a first selecting means SL1, and the digital audio signal b1 is stored in a first storage means MR1 to perform the recording operation. A second converting means TR2 converts a digital audio signal b2 to an analog audio signal c in the conversion range selected in accordance with amplitude information of the digital audio signal b2 by a second selecting means SL2, and the analog audio signal c is inputted to an output means OP and is outputted from a speaker as sounds. Thus, the quantity of stored information is reduced to follow the waveform whose amplitude is quickly changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording and reproducing method and a recording and reproducing device.

[Prior Art] PCM (Pu1s eCod
ed Modulation) method is known.

In addition, ADPCM (
Adaptive Differential P
The U1SE Coded Modulation) method is known.

[Problem to be solved] The PCM method described above has a problem in that the amount of information to be stored increases.

Further, in the ADPCM method, since the difference data between adjacent sound data is stored, there is a problem that it is impossible to follow a waveform whose amplitude suddenly increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording and reproducing method that requires only a small amount of information to be stored and can follow even waveforms whose amplitudes change rapidly, and to provide a recording and reproducing apparatus for the same.

[Means for determining the problem] The recording power method in the present invention is based on the original sound (the vibration of No. 1i is also 1
°l↑1? The original sound signal is converted into a digital sound signal in a conversion range selected according to the information, and the converted digital sound signal is stored and recorded.

The recording device il+' for realizing the above-mentioned recording method includes a first selection means for selecting a conversion range according to amplitude information of the original sound signal, and a first selection means for selecting a conversion range according to the amplitude information of the original sound signal. It consists of a first conversion means for converting into a digital sound signal, and a first storage means for storing the digital sound signal converted by the first conversion means.

Further, the reproduction method according to the present invention reads a stored digital sound signal, converts the digital signal into an analog sound signal in a conversion range selected according to amplitude information of the digital sound signal, and performs reproduction. .

A reproduction device for realizing the above reproduction method includes a second storage means for storing a digital sound signal, a second selection means for selecting a conversion range according to amplitude 1 information of the digital sound signal, and a second selection means for selecting a conversion range according to amplitude 1 information of the digital sound signal. and a second conversion means for converting the digital sound signal into an analog sound signal in the conversion range selected by the second selection means.

[Example code] The present invention will be explained below with reference to the drawings.

As shown in FIG. 3, the principle of the present invention is to convert the original sound signal (waveform shown by the peak) into a digital sound signal in a conversion range (shown by the broken line) selected according to the amplitude of the original sound signal. It is converted into . In other words, as shown in the figure, when the amplitude of the original sound signal is large, the original sound signal is converted in a wide conversion range, and when the amplitude of the original sound signal is small, the original sound signal is converted in a narrow conversion range. It is.

For example, if a digital sound signal is configured with a constant number of bits in any conversion range, it is possible to record and reproduce the same sound quality regardless of the magnitude of the amplitude of the original sound signal.

Basic Configuration Example An example of the basic configuration of a recording device and a playback device according to the present invention will be explained using FIGS. 1 and 2. FIG.

Note that the recording device shown in FIG. 1 and the playback device shown in FIG. 2 can be regarded as separate devices, but unless otherwise specified,
The following explanation assumes that the sound recorded by the recording device shown in FIG. 1 is reproduced by the playback device shown in FIG. 2.

FIG. 1 is a block diagram showing an example of the basic configuration of a recording device.

IP is an input means and outputs the original sound signal "a". In this 8m example, the input means IP is made up of a microphone, an additional 11 circuit, etc., and inputs sounds such as voices. The original sound signal is usually an analog signal, but it may be a digital signal.

The SLI is the first selection means and selects a conversion range according to the amplitude of the original sound signal "a" output from the second input means 0IP. Preferably, the width of each conversion range is selected to vary in equal number of fibers.

Expressing this mathematically, A-AO・B...
・・・・・・・・・(1) However, A・・・・・・Width of each conversion range AO・・・・
・Maximum conversion range width B・・・・・・Positive number n smaller than 1・・・・・・
...becomes an integer. For example, if B −1/2 is used in equation 1, the width of each conversion range is 1/2 XAO, 1/4×A with respect to the maximum conversion range width AD, as shown in Figure 3
O1......

TRI is a first conversion means, and the first selection means S
The original sound signal "a" is converted into a digital sound signal in the conversion range selected by the LI, and a digital sound signal "b1" is output. A digital sound signal usually consists of a fixed number of bits and does not change depending on the conversion range.

1 MRI is the first storage means, and the first conversion means T
It stores the digital sound signal "bl" output from the RI. This first storage means MRI is usually RAM.
(Random Access Memory)
It is composed of etc.

The operation of the recording device shown in FIG. 1 is as follows.

Sounds such as voices and melodies are input to the input means IP. After the sound is detected by the microphone, it is amplified by the amplifier circuit and output as the original sound signal "a".

The first conversion means TRI converts the original sound signal "a" into a digital signal with a predetermined number of bits at a predetermined time interval in the conversion range selected by the first selection means SLl, and converts the original sound signal "a" into a digital sound signal "bl". Output. In other words, a digital sound signal “
bl" is the original sound signal "a" sequentially converted into digital data. The conversion range at this time is selected by the first selection means SLI. Note that the first selection means SLl
The conversion range information d1 output from the conversion range d1 may be information representing the fear of the conversion range, or may be information that increases or decreases the conversion range.

By the way, in this embodiment, the conversion range selected by the first selection means SLl is selected by inputting the digital sound signal "bl" to the first selection means SLl, as shown in FIG. . However, the conversion range can also be selected, for example, by inputting the original sound signal "a" to the first selection means SLI. In short, the signal for selecting the conversion range may be any signal that can be obtained by inputting a signal corresponding to the amplitude information of the original sound signal to the first selection means SLI.

The digital sound signal output from the first conversion means TRI
Each digital data of "bl" is sequentially stored in the first storage means MR.
It is stored in I.

The recording operation is performed as described above.

FIG. 2 is a block diagram showing an example of the basic configuration of the playback device.

MR2 is a second storage means in which digital sound signals are stored, and is usually constituted by a ROM (Read O3 nI y Memory) or the like. A digital sound signal usually consists of a fixed number of bits and does not change depending on the conversion range.

Further, it is preferable to use a digital sound signal obtained by the recording device as the digital sound signal stored in the second storage means MR2.

SL2 is a second selection means, and the second storage means M
The conversion range is selected according to the amplitude information of the digital sound signal "b2" output from R2. The width of each conversion range is determined by the first selection means SL in the recording sound device.
It is preferable to select according to l. That is, it is preferable that the width of each conversion range is selected so as to vary in a uniform manner.

TR2 is a second conversion means, and the second selection means S
In the conversion range selected by L2, the digital sound signal “b2
'' into an analog sound signal ``C''.

OP is an output means, which inputs the analog sound signal "C". In this embodiment, the output means 40P is composed of an amplifier circuit, a speaker, etc., and inputs the analog sound signal "C". is converted to sound output.

The operation of the playback device shown in FIG. 2 is as follows.

The digital sound signal output from the second storage means MR2
Each digital data of "b2" is sequentially input to the second conversion means TR2, and is converted into an analog sound signal C" in a conversion range selected by the second selection means SL2. Note that the conversion range information amount 2 output from the second selection means SL2
may be information representing the width of the conversion range, or may be information that increases or decreases the conversion range.

By the way, in this embodiment, the conversion range selected by the second selection means SL2 is selected by inputting the digital sound number "b2" to the second selection means SL2, as shown in FIG. be done. However, the conversion range may be selected by inputting the analog sound signal "C" to the second selection means SL2, for example. In short, it is sufficient if a signal corresponding to the amplitude information of the digital sound signal is input to the second selection means SL2 and selected.

The analog sound signal output from the second conversion means TR2
C'' is input to the output means OP, amplified by the amplification circuit, and then output as sound from the speaker.

The reproduction operation is performed as described above.

In the basic configuration example described above, when recording, the original sound signal is converted to a digital sound signal in a conversion range selected according to the amplitude of the original sound signal, and when playing back, the digital sound signal is converted into a digital sound signal by converting the amplitude of the digital sound signal. Since the signal is converted into an analog sound signal in a conversion range selected according to the signal, the amount of information to be stored is reduced, and a recording and playback device that can follow waveforms whose amplitude changes rapidly can be obtained.

Next, regarding an example in which each component of the recording device and playback device described in the above “Example of configuration” is shown as a specific example,
This will be explained below.

Note that in each of the following embodiments, points not specifically mentioned are the same as in the above-mentioned "basic configuration example".

Embodiment 1 A first embodiment based on the recording device and playback device described in the above “Basic configuration example” will be described using FIGS. 4 and 5.

Note that the recording device shown in FIG. 4 and the playback device shown in FIG.
A description will be given assuming that the sound recorded by the recording device shown in the figure is played back by the playback device shown in FIG.

FIG. 4 is a block diagram showing the recording device in the first embodiment.

The input means IP, the first storage means MRI, and the first conversion means TRI are the same as those described in ]21 "Basic configuration example".

The first selection means SLI includes a first amplitude level detection means S
It is composed of DI and first conversion range selection means TS1.

The first amplitude level detection means SDI detects the amplitude level according to the amplitude information of the original sound signal "a" outputted from the input means 7 IP. In the main fire example, the fourth
As shown in the figure, the digital sound signal "bl" is input to the first vibration level detection means S1. However, the signal input to the first amplitude level detection means SDI may be any signal that corresponds to the amplitude information of the original sound signal.

The first conversion range selection means TSI receives information on the amplitude level detected by the amplitude level detection means SDI of the second memory 1 and selects the optimum conversion range.

The operation of the recording device shown in FIG. 4 is as follows.

The original sound signal "a" is input to the first conversion means TRI,
The digital sound signal "bl" is sequentially converted into each digital data in the conversion range selected by the first conversion range selection means TSI.

Each digital signal in the digital sound signal "bl" is stored in the first storage means MRI, and is sequentially input to the first amplitude level detection means SDI, so that the amplitude level of each digital data is detected. .

Each amplitude level information detected for each digital data of the digital sound signal "bl" is sequentially input to the first conversion range selection means TSI, and each continuous amplitude level information (for example, 128 bytes of information) The optimal conversion range is selected based on .

The recording operation is performed in the following manner.

FIG. 5 is a block diagram showing a reproducing apparatus in the first embodiment.

The output means OP1P2O3 storage means MR2 and the second conversion means TR2 are the same as those described in "1. Basic configuration example".

The second selection means SL2 includes a second amplitude level detection means S
D2 and second capsulectomy selection means TS2.

The second amplitude level detecting means SD2 has a second amplitude level detecting means SD2.
The amplitude level corresponding to the amplitude information of the digital sound signal "b2" outputted from R2 is detected. In this embodiment, as shown in FIG. 5, the digital sound signal "b2" is input to the nine second vibration bell detection means SD2. However, the f signal input to the second shaking bell detection means SD2 may be any signal that corresponds to the amplitude information of the digital sound signal.

The second conversion range selection means TS2 receives information on the amplitude level detected by the second amplitude level detection means SD2 and selects the optimum conversion range.

The operation of the reproducing apparatus shown in FIG. 5 is as follows.

The digital sound signal output from the storage means MR2 of @2
Each digital data of b2'' is input to the second converting means TR2, and is sequentially input to the second amplitude level detecting means S.
One level is detected for each digital data input to D2.

Each amplitude level information detected for each digital data of the digital sound signal "b2" is sequentially input to the second conversion range selection means TS2, and each continuous amplitude level information (for example, 128 bytes of information The optimal conversion range is selected based on the

In the second conversion means, the second conversion range selection means TS2
The digital sound signal "b2" is converted into the analog sound signal "C" in the conversion range selected in .

The reproduction operation is performed in the following manner.

Here, the first conversion range selection means TS1 and the second conversion range selection means TS2, the first amplitude level detection means SDI and the second amplitude level detection means SD
A specific example of No. 2 and its operation will be explained.

The first conversion range selection means TSI and the second conversion range selection means TS2 can have the same configuration;
The amplitude level detection means SDI and the second amplitude level detection means SD2 can also have the same configuration. The configuration is shown in FIG. 6.

From the first converting means TR1 and the second converting means TR2 shown in FIGS. 4 and 5, each digital data 1 and b2 of the digital sound signal is sequentially input to the 1 comparator 11.

In the comparator 11, the digimole sound signals b1 and b2
The value of the amplitude level included in is the maximum value in the conversion range selected at that time (111...1)
and the maximum value in the conversion range of 1/2 (011
......1) Determine whether it is larger than 1'.

When the value is greater than the former value, "1" is output to the terminal Pi, and when it is greater than the latter value, "1" is output to the terminal P2.

Each time the terminals PI and P2 of the comparator 11 become "1", the output of the terminals PI and P2 causes the counter 1 to
2 each independently. Also, each time 1 data is input to the comparator 11, the counter 1
3 (128 base).

) to count up.

When the count value of the counter 13 reaches “128”, the maximum value (11
The first count value that gives the number of outputs larger than 1...1) and the maximum value (011...1) in the conversion range of 1/2 of the first count value (011...1) A second count value giving the number of output values is output from the counter 12, respectively. The comparator 14 converts each of the above count values to a first reference value (“3”).
shall be. ) and the second reference value (set to "3"). When the first count value of the counter 12 is equal to or greater than the first reference value "3", the conversion range designation register 16
When the second count value of the counter 12 is less than or equal to the second reference value "3", the conversion range of the conversion range designation register 16 is decreased by one step. As a result, the conversion range designation register 16 outputs optimal conversion range information d1 and d2.

Note that the data in the counter 12 is cleared through the delay circuit 15 by the output of the counter 13 after the comparison operation by the comparator 14 is completed.

The recording device and playback device in this embodiment can automatically select a conversion range by the first conversion range selection means TS1 and the second conversion range selection means TS2. Further, since the conversion range can be automatically selected, there is no need to store conversion range information in the first storage means MRI and the second storage means MR2, and the storage capacity can be reduced.

Embodiment 2 A second embodiment based on the recording device and playback device described in Section 1 “Basic configuration example” will be described using FIGS. 7 and 8.

Note that the recording device shown in FIG. 7 and the playback device shown in FIG.
A description will be given assuming that the sound recorded by the recording device shown in the figure is played back by the playback device shown in FIG.

FIG. 7 is a block diagram showing the recording device in the second practical example.

The input means IP, the first storage means MRI, and the first conversion means TRI are the same as those described in the "basic configuration example" above.

The first selection means SLI is composed of a third amplitude level detection means SD3, a third conversion range selection means TS3, and a control data insertion means CDI.

The third amplitude level detection means SD3 and the third conversion range selection means TS3 are similar to the first amplitude level detection means SDI and the first conversion range selection means TSI described in "Embodiment 1" above. be.

The control data insertion means CDI inserts the conversion range information selected by the third conversion range selection means TS3 into each digital data of the digital sound signal "b1" outputted from the first conversion means TRI. be.

The operation of the recording device shown in FIG. 7 is as follows.

The original sound signal "a" is input to the first conversion means TRI,
The digital sound signal "bl" is sequentially converted into each digital data in the conversion range selected by the third conversion range selection means TS3.

Each digital data in the digital sound signal "bl" is input to the control data insertion means CDI, and is also sequentially input to the third amplitude level detection means SD3, and the amplitude level of each digital data is detected.

In the third conversion range selection means TS3, a conversion range is selected by performing the same operation as that described in FIG. 6 in "1. Example 1".

In the control data suppression means CDI, the following (1) to (
One of the operations 3) is performed.

(1) Insert conversion range information for each digital data in the digital sound signal "b1".

(2) Input conversion range information for each predetermined number of digital data in the digital sound signal "b1". For example, 1 of the digital data in the digital sound signal “bl”
Insert 1 byte of conversion range information every 28 bytes.

(3) Insert conversion range information every time the conversion range changes.

Note that in (1) to (3) above, the input data may be the conversion range itself, or may be information for increasing or decreasing the conversion range.

The conversion range information outputted from the control data insertion means CDI is outputted together with the digital sound signal and stored in the first storage means MHI.

The recording operation is performed as described above.

FIG. 8 is a block diagram showing a reproducing apparatus in a second embodiment.

The output means OP, the P2O3 storage means MR2, and the second conversion means TR2 are the same as those described in the "basic configuration example" above.

The second selection means SL2 is composed of a control data extraction means CDO and a fourth conversion range selection means TS4.

The control data extracting means CDO extracts conversion range information output from the second storage means MR2 together with the digital sound signal.

The fourth conversion range selection means TS4 selects a conversion range based on the conversion range information 7 extracted from the control pig extraction means CDO.

The operation of the playback device shown in FIG. 8 is as follows.

The second storage means MR2 outputs conversion range information together with the digital sound signal. The conversion range information is extracted by the control data extraction means CDO and sent to the fourth conversion range selection means TS4.

On the other hand, the digital sound signal is sent to the second conversion means TR2,
The signal is converted into an analog sound signal "C" in the conversion range selected by the fourth conversion range selection means TS4.

Note that the second storage means MR2 includes the first memory shown in FIG.
Data stored in the storage means MRI is stored. Therefore, from the control data extraction means CDO, the seventh
The data extracted by the control data insertion means CDI shown in the figure is extracted.

The fourth conversion range selection means TS4 selects a conversion range based on the conversion range information extracted by the control data extraction means CDO.

The reproduction operation is performed as described above.

8. The recording device and playback device in this embodiment are provided with the control data insertion means CDI and the control data extraction means CDO, so that the conversion range information can be stored separately from the digital sound signal. Therefore, the configuration of the playback device can be particularly simplified.

Embodiment 3 Using FIG. 9 and FIG. 10, a third
An example of this will be explained.

Note that the recording device shown in FIG. 9 and the playback device shown in FIG. The following explanation assumes that the sound recorded by the device is played back by the playback device shown in FIG.

FIG. 9 is a block diagram showing a recording device in a third embodiment.

The input means IP1P2O3 storage means MHI and first selection means SLI are the same as those described in the "Basic Configuration Example" above.

The first conversion means TRI is the first A/D conversion means ADI.
and a signal compression means SCM.

The first A/D conversion means ADI performs A/D conversion on the analog original sound signal "a" inputted from the input means IP.

The signal compression means SCM converts the A/D conversion signal "f1" obtained by the first A/D conversion means ADI into the first selection means S
In the conversion range selected by LI, the A/D conversion signal “f1
is converted into a compressed signal with a smaller number of bits than the number of bits of ``, thereby obtaining a digimole sound signal ``b1''.

The operation of the recording device shown in FIG. 9 is as follows.

The analog original sound signal “a” is sent to the first A/D conversion means A.
A/D conversion is performed at the DI, and an A/D conversion signal "fl" is obtained. Although the number of bits of the A/D conversion signal "fl" may be selected as appropriate, it is assumed here that it is composed of 11 bits (however, 1 bit is a sign bit).

The signal compression means SCM converts the A/D converted signal "fl" into
In the conversion range selected by the first selection means SLI, A/
It is converted into a compressed signal having a smaller number of bits than the number of bits of the D-converted signal "f1" (here, it is assumed to be 5 bits, and 1 bit is a sign bit). As a result, the signal compression means SC
A digital sound signal "bl" is output from M.

The digital sound signal "bl" is stored in the first storage means MRl and inputted to the first selection means SLl,
Conversion range information is output from the first selection means SLI.

The recording operation is performed as described above.

Here, a specific example of the signal compression means SCM and its operation will be explained using FIG. 11.

In the example shown in FIG. 11, the width of each conversion range is set to 1/2 with respect to the maximum conversion range AO, as shown in FIG.
XAO, 1/4 XAO, ......

First, the principle will be explained.

1 For example, when the conversion range changes from AO to 1/2XAO, a binary value of "0111" in the former conversion range is represented by a binary value of "1110" in the latter conversion range. This corresponds to shifting the data by 1 bit.

That is, when the conversion range is reduced to 1/2, it is sufficient to shift the data expressed in binary code by 1 bit.

Similarly, if the conversion range is reduced to 1/4, the data expressed in binary code may be shifted by 2 bits. Figure 11 (B) shows that the conversion range is 1/8 of the maximum conversion range.
This shows the case where the data is shifted by 3 bits.

The example shown in FIG. 11 will now be explained with reference to the above.

FIG. 11(A) shows the signal compression means SCM in FIG.
This is what is shown.

Conversion range information "dl" is sent to the shift control circuit 31 from the first selection means SLI in FIG. The conversion range information "d1" may be information representing the width of the conversion range, or may be information that increases or decreases the conversion range by 2. The shift control circuit 31 outputs shift data based on the conversion range information "dl".

Based on the shift data output from the shift control circuit 31, the shift circuit 32 uses 11 bits (1 bit is a sign bit and the other bits are absolute value bits).

) of the A/D converted signal "f1" other than the sign bit is shifted by a predetermined bit, and a 4-bit absolute value signal is output.

The code detection circuit 33 also receives the A/D conversion signal "f1" and extracts the code bit.

The maximum value setting circuit 34 sets the absolute value signal to the maximum value when the data overflows the conversion range.

In the compressed data forming means, a sign bit (1 bit) and an absolute value are added to the data obtained from the shift circuit 32, the n-number detection circuit 33, and the maximum value setting circuit 34, as shown in Figure 11 (C). A compressed signal consisting of bits (4 bits) is formed and a digital sound signal b1 is output.

FIG. 10 is a block diagram showing a reproducing apparatus in a third embodiment.

The output means OP1P2O3 storage means MR2 and second selection means SL2 are the same as those described in "1. Basic configuration example".

The second conversion means TR2 is the first D/A conversion means DAI.
and signal expansion means SEP.

The signal expansion means SEP converts the digital sound signal "b2" into an expanded signal "fl" having a larger number of bits than the number of bits of the digital sound signal "b2" in the conversion range selected by the second selection means SL2. It is something to do.

The first D/A conversion means DAI performs D/A conversion on the expanded signal "fl" outputted from the signal expansion means SEP.

The operation of the reproducing apparatus shown in FIG. 10 is as follows.

The digital sound signal "b2" (here, 5 bits and 4 bits, and 1 bit is a sign bit) is input to the second selection means SL2, and is also input to the signal expansion means SEP.

The signal expansion means SEP converts the digital sound signal "b2" to 11 in the conversion range selected by the second selection means SL2.
It is converted into an expanded signal "f2" of bits (however, 1 bit is a sign bit).

In the first D/A capsulation means DAI, the extension signal f2'' is
/At and outputs an analog sound signal "C".

The reproduction operation is performed as described above.

Here, a specific example of the signal expansion means SEP and its operation will be explained using FIG. 12.

In the example shown in FIG. 12, the width of each conversion range is 1/2 x A llllX with respect to the width Amx of the maximum conversion range.
%1/4XAIIIX%... It is a bound product.

The basic operating principle of the signal expansion means SEP is the reverse of the operation of the signal compression means SCM described in FIG. 11, and the principle is as already described in 5.

FIG. 12(A) shows the signal expansion means SE in FIG.
This shows P.

The data separation means 45 receives a digital sound signal "
The digital sound signal "bl" input to the data separation means 45 is separated into a sign bit and an absolute value bit (absolute value signal).

Conversion range information "d2" is sent to the shift control circuit 41 from the second selection means SL2 in FIG.

The conversion range information "d2" may be information representing the width of the conversion range, or may be information that increases or decreases the conversion range. The shift control circuit 41 outputs shift data based on the conversion range information "d2".

In the shift circuit 42, based on the shift data output from the shift control circuit 41, as shown in FIG. 12(B), the 4-bit absolute value signal is shifted by the bit of the compartment.
Outputs a 10-bit D/Am conversion signal 6. At this time, bits other than the 4 bits shifted from the absolute value signal become "0".

The data combination means 44 combines the 10-bit D/A conversion signal and the 1-bit code signal outputted from the code detection means 43 into an 11-bit signal as shown in FIG. 12(C). , to the first D/A conversion means DAI in FIG.

Since the recording device and playback device in this embodiment are provided with the signal compression means SCM and the signal expansion means SEP, the amount of information to be stored can be reduced. In particular, the width of each conversion range is defined as the width of the maximum conversion range Amx.
1/2 xAInx, 1/4 xAIIlxl...
..., the signal compression means SCM and the signal expansion means SEP can be easily configured, and the overall configuration becomes simple.

Embodiment 4 A fourth embodiment based on the recording device and playback device described in the above “Basic configuration example” will be explained using FIGS. 13 and 14.

The recording device shown in Fig. 13 and the playback device shown in Fig. 14 7 can be considered as separate devices, but in the following explanation, unless otherwise specified, the recording device shown in Fig. 13 will be used as the recording device shown in Fig. 14. The sound recorded by the device is recorded in the 14th
The explanation will be given assuming that the playback device shown in the figure is used to playback.

FIG. 13 is a block diagram showing a recording device in a fourth embodiment.

The input means IP, the first storage means MHI, and the first selection means SLI are the same as those described in the "basic configuration example" above.

The first conversion means TRI is a second A/D conversion means AD2.
and A/D conversion range changing means ADTL.

The second A/D conversion means AD2 receives an analog original sound signal "
A' is A/D converted and a digital sound signal "bl" is output. In this embodiment, the above-mentioned Digimol sound signal "
b1'' is composed of 5 bits (1 bit is a sign bit).

The A/D conversion range changing means ADTL changes the maximum input range of the second A/D conversion means AD2 in accordance with the conversion range selected by the first selection means SLI.

The operation of the recording device shown in FIG. 13 is to change the maximum input range of the second A/D conversion means AD2 depending on the amplitude of the original sound signal "a". When the amplitude of “a” is large, widen the maximum input range,
When the amplitude of the original sound signal "a" is small, the maximum input range may be narrowed. Specifically, the details are as follows.

A conversion range is selected by the first selection means SLl based on the digital sound signal "bl" corresponding to the amplitude of the amplitude of the original sound signal "a".

The A/D converter ADT changes the maximum input range of the second A/D converter AD2 in accordance with the conversion range. The maximum input range of the second A/D conversion means AD2 can be changed by, for example, changing the reference voltage for A/D conversion.

The second A/D conversion means AD2 performs A/D conversion on the original sound signal "a" in the selected 9 maximum input range to obtain a digital sound signal "bl".

The recording operation is performed as described above.

FIG. 14 is a block diagram showing a reproducing apparatus in a fourth embodiment.

The output means OP1P2O3 storage means MR2 and the second selection means SL2 are the same as those described in the "basic configuration example" above.

The second conversion means TR2 is a second D/A conversion means DA2.
and a D/A converter changing means DATL.

The second D/A conversion means DA2 converts the digital sound signal "b2" into a digital sound signal "b2".
`` is D/A converted and an analog sound signal C'' is output. In this embodiment, "1 digital sound signal "b2
" is 5 bits (however, 1 bit is a sign bit.

).

The D/A conversion range changing means DATL switches the maximum output 0 range of the second D/A conversion means DA2 in accordance with the conversion range selected by the second selection means SL2.

The operation of the playback device shown in FIG. 14 is based on the digital sound signal "
Depending on the amplitude of the sound signal determined from “b2”,
This is to change the maximum output range of the second D/A conversion means DA2. For example, when the amplitude of the sound signal determined from the digital sound signal "b2" is large, the maximum output range may be widened, and when the amplitude is small, the maximum output range may be narrowed.

Specifically, the details are as follows.

The conversion range is selected by the second selection means SL2 based on the transfer information (the amplitude of the sound signal) of the digital sound signal "b2".

The D/A conversion range changing means DATL changes the maximum output range of the second D/A conversion means DA2 according to the conversion range. The maximum output range of the second D/A conversion means DA2 can be changed, for example, by changing the reference voltage for D/A conversion.

The second D/A conversion means DA2 performs D/A conversion on the digital sound signal "b2"1 in the selected maximum output range, and outputs an analog sound signal "C".

The recording device and the playback device in this embodiment are the second A
The maximum input range of the second A/D conversion means AD2 and the second D
Since the maximum output range of the /A conversion means DA2 is optimally set according to the amplitude of the sound signal, recording and reproduction can be performed with high quality even if the amount of information to be stored is small.

Example 5 The above “basic configuration example” is
A fifth embodiment based on the recording device and playback device described above will be explained.

Note that the recording device shown in Fig. 15 and the 14th recording device shown in Fig. 16 can be regarded as separate devices, but in the following explanation, unless otherwise specified,
A description will be given assuming that the sound recorded by the recording device shown in FIG. 15 is played back by the playback device shown in FIG. 16.

2 FIG. 15 is a block diagram showing a recording device in the fifth embodiment.

The input means IP, the first storage means MRI, and the first selection means SLI are the same as those described in the "basic configuration example" above.

The first conversion means TRI is a third A/D conversion means AD3.
, variable input means CHI and first gain changing means GTI
It consists of

The variable input means CHI obtains an amplified signal by amplifying the analog original sound signal "a", and is constituted by an amplifier circuit, etc.The variable input means CHI may be one that attenuates the original sound signal "a". , an additional payment of 1, and an attenuated one.

The third A/D conversion means AD3 includes the variable input means CH
The amplified signal obtained by I is A/D converted and a digital sound signal "bl" is output.

In this embodiment, it is assumed that the digital sound signal "bl" is composed of 5 bits (however, 1 bit is a sign bit).

The first gain changing means GTI changes the gain of the variable input means CHI in accordance with the conversion range selected by the first selecting means 3 SLI.

The operation of the recording device shown in FIG. 15 is to change the gain (amplification degree) of the variable input means CHl according to the magnitude of the amplitude of the original sound signal "a". When the vibration axis is large, the gain is reduced and the original sound signal “a”
When the amplitude of is small, the gain can be increased. Specifically, the details are as follows.

A conversion range is selected by the first selection means SLl based on the digital sound signal "bl" corresponding to the magnitude of the amplitude of the original sound signal "a".

The first gain changing means GTI changes the gain of the variable input means CHI according to the conversion range.

The variable input means CHI outputs the original sound signal with the selected gain.
a” is amplified.

In the third A/D conversion means AD3, the variable input means CHI
The amplified signal obtained in step A/D is converted into 5 bits (1 bit is a sign bit).

) outputs the digital sound signal "bl".

4 The recording operation is performed in the following manner.

FIG. 16 is a block diagram showing a playback device in the fifth embodiment.

The output means OP1P2O3 storage means MR2 and second selection means SL2 are the same as those described in -1- "Example of configuration on the left side".

The second conversion means TR2 is the third D/A conversion means DA3.
, variable output means CHO and second gain changing means GT2
It consists of

The third D/A conversion means DA3 converts the digital sound signal "b2" into
” to D/Ai and outputs a D/A converted signal. In this embodiment, the digital sound signal “bl” is 5
It is assumed that it consists of bits (however, 1 bit is a sign bit).

The variable output means CHO is connected to the third D/A conversion means DA.
It amplifies the D/A converted signal obtained in step 3, and is composed of an amplifier circuit and the like.

Note that the variable output means CHO may be one that attenuates the D/A converted signal, or may be one that amplifies and attenuates the D/A conversion signal.

The second gain changing means GT2 includes the second selecting means SL.
The gain of the variable output means CHO is changed in accordance with the conversion range selected in step 2.

The operation of the recording device shown in FIG. 16 is based on the digital sound signal "
Depending on the amplitude of the sound signal determined from b2″,
This is to change the gain 111 (amplification degree) of the variable output means CHO. For example, when the amplitude of the sound signal determined from the digital sound signal "b2" is large, the gain may be increased, and when the amplitude is small, the gain may be reduced. Specifically, the details are as follows.

In the third D/A conversion means DA3, 5 bits (however,
One bit is a sign bit. ) digital sound signal “b
2'' is D/A converted and a D/A converted signal is output.

On the other hand, the second selection means SL2 selects the digital sound signal "b".
Based on the amplitude information (the magnitude of the amplitude of the sound signal) of 2'', the second selection means SL2 selects 6 conversion ranges.

The second gain changing means GT2 changes the gain of the variable output means CHO according to the selected conversion range.

The variable output means CHO amplifies the D/A converted signal with a selected gain.

The recording operation is performed as described above.

The recording device and playback device in this embodiment have a first advantage. 11 variable 1y means GTI and second gain changing means GT
2, the gain of the 6J variable input means CHI and the gain of the variable output means CHO are optimally set according to the amplitude of the sound signal, so even if the amount of information to be stored is small, recording and playback can be performed with high sound quality. can.

Embodiment 6 Next, as a sixth embodiment, a specific example of the recording device and reproduction device described in the above “Embodiment 3” will be explained using FIGS. 17 and 18. This embodiment relates to specific examples of the signal compression means SCM shown in FIG. 9 and the signal expansion means SEP shown in FIG. 10.

First, before explaining the specific configuration, the principle will be explained.

When the width of each conversion range is selected based on the number of equalized fibers, as already mentioned, it is expressed as follows.

A-AO・B ・・・・・・・・・・・・・・・(1
), A...... Width Ao of each conversion range...
・Fuku B of the maximum conversion range・・・・・・・・・Positive number n smaller than 1・・・・・・
...Integer Here, each constant in equation (1) is expressed as follows.

B-(1/2) 11k ・・・・・・・・・(2)n
-4i+j ・・・・・・・・・・・・・・・・・・
(3) However, k・・・・・・・・・ Positive number i that is larger than 1.
...0.1.2, ...j...
・0.1.2,... k −1 As a result, (1
) The formula is as follows.

A=AO・+(1/2)'c)(4I+j)...(4
)8 Here, in equation (4), if k-4 is set, then the following is obtained.

A=AO・+(1/2)1141(”+j)=AO・l
(1/2)'l 1(1/2)j/'l...
(5) Tashi, i ・・・・・・・・・ 0 , 1 , 2 , ・・・
. . . j . . . 0, 1 , 2, 3 Therefore, the relationship of equation (5) is shown in FIG. 20. For example, if we look at j-0, we can see that each time the value of i'' increases by 1, the value of "A" becomes 1/2.

The same applies to j-1, 2, and 3. In other words, the width of the conversion range (the value of "A") decreases by half every four ranges. As already mentioned, when the conversion range is reduced to 1/2, each binary data only needs to be shifted by 1 bit.

With reference to what has been said above, Figures 17 and 18
An example of the figure will be explained.

FIG. 17 shows the signal compression means SCM in FIG. 9.

9 The circuit shown in this example converts the 11-bit (however, 1 bit is a sign bit) data "f1" output from the first A/D conversion means ADI in FIG. 9 into 5-bit ( However, 1 bit is the sign bit) data “bl”
The data is compressed into 100% and sent to the first storage means MRI in FIG.

Conversion range information "dl" is input to the range designation circuit 51 from the first selection means SLI in FIG. The conversion range information "dl" may be information representing the width of the conversion range, or may be information that increases or decreases the conversion range. The range designation circuit 51 sends 2-bit and 3-bit conversion range designation information to a data storage circuit 56 and a shift circuit 52, which will be described later, respectively.

A clock signal “g” is input to the counter circuit 57,
It is counted up sequentially. This counter circuit 57 is 1
It is a hexadecimal counter, and a 4-bit count value is sent to a data storage circuit 56, which will be described later, each time it is counted up.

0 data storage circuit 56 is composed of ROM (read only memory), the upper 2 bits of the address are specified by the range specifying circuit 51, and the lower 4 bits are specified by the counter circuit 5.
7. The data structure in the pig storage circuit 56 is as shown in FIG. 19, and each data is divided into four blocks corresponding to the conversion range. Address “63” “62,” “48”
are each binary data “1111000000
"1110000000"... "ooo
oooooooo" is stored. That is, the lower 4 bits of the address and the upper 4 bits of the binary data are exactly the same. Addresses "47" to "32"
, stores data "960' to 1/4° "0" stored at addresses "631 to "48" each multiplied by "(1/2)." Address "31" ~ “16” stores data obtained by multiplying the data “960” ~ “0” stored at addresses “63” ~ “48” by “ (2/4□ 1/2), respectively. . Addresses “l5” to “0” contain data “960” to “0” stored in addresses “63”1 to “48”.
, respectively, are stored as pigs multiplied by "(1/2) 3/4".

Shift circuit 52 receives 10-bit data from data storage circuit 56 . This 10-bit data is data stored at an address designated by range designation circuit 51 and counter circuit 57. Shift l! , u circuit 52 is shifted by a predetermined number of bits according to the 3-bit range designation information sent from the range designation 1111 path 51.

The sign detection circuit 53 detects the first signal from among the 11-bit (1 bit is a sign bit) A/D conversion data "fl" output from the first A/D conversion means ADI in FIG. The number bit is extracted.

In the coincidence detection circuit 58, every time the counter circuit 57 is counted up by the clock signal "g", the shift circuit 52 is
Shift data (10 bits) output from A/D!
Compares the 2 absolute value data (10 bits) of the small exchange data and generates an output when the two match.In principle, the absolute value data is 210
However, the nft data output from the shift circuit 52 takes only a limited value, corresponding to the binary data shown in FIG. Therefore, in reality,
When the absolute value data for each shift data is within a certain range, both data are considered to match. For example, when certain absolute value data DX is input to the coincidence detection circuit 58, when shift data that is less than or equal to the absolute value data DX and closest to the absolute value data Dx is input to the coincidence detection circuit 58, both data are considered to match. When both data match, the gate circuit 59 is opened, and the current count value of the counter circuit 57 is inputted to the data forming circuit 55, which will be described later. Therefore, the count value at the time when both data match becomes absolute value data compressed to 4 bits. That is, at the time when both data match, the lower 4 bits of the specified address for the data storage circuit 56 become the absolute value data compressed to 4 bits as they are.

In the data forming circuit 55, each of the above data is
Compressed data "bl" of 5 bits (4 bits are absolute value data and 1 bit is code data) is formed and sent to the first storage means MRI in FIG.

FIG. 18 shows the signal expansion means SEP in FIG. 10.

The circuit shown in this example converts the data "b2" of 5 bits (1 bit is a sign bit) output from the second storage means MR2 in FIG. 10 into 11 bits (
However, the first D/A conversion means DAI in FIG.
It is sent to Note that the data stored in the second storage means MR2 shown in FIG. 10 is the same as the data stored in the first storage circuit MRI shown in FIG.

The data separation circuit 65 converts the 5-bit compressed data "b2" sent from the 42nd storage means MR2 shown in FIG. 10 into 4-bit absolute value data and 1-bit code data. Separate into two parts.

Conversion range information "d2" is input to the range designation circuit 61 from the second selection means SL2 in FIG. The conversion range information "d2" may be information representing the width of the conversion range, or may be information that increases or decreases the conversion range. The range designation circuit 61 sends 2-bit and 3-bit conversion range designation information to a data storage circuit 66 and a shift circuit 62, respectively.

The data storage circuit 66 is composed of a ROM (read only memory), the upper 2 bits of the address are specified by the range specifying circuit 61, and the lower 4 bits are specified by the data separation circuit 65. The data structure in the pig storage circuit 66 is similar to that of the data storage circuit 56 in FIG. 17, and is as shown in FIG. 19.

The shift circuit 62 receives 10-bit data from the data storage circuit 66 . The 10-bit data input to the shift circuit 625 is sent to the range specifying circuit 61.
The data is shifted by a predetermined number of bits according to the 3-bit range designation information sent from.

In the data combination circuit 64, the 1 output from the shift circuit is
From the 0-bit absolute value data and the 1-bit sign data output from the data separation circuit, 11-bit expanded data "f2" is formed, and the first D/A in FIG.
It is sent to the conversion means DAI.

The basic configuration example and the embodiments have been described above, but in the basic configuration example and each embodiment, some of the constituent elements can be shared by the recording device and the lJru device. Therefore, by appropriately sharing the constituent elements, it is possible to easily configure a recording/playback device that functions as both a recording device and a playback device.

It goes without saying that the principles, devices, etc. described in each embodiment can be combined as appropriate.

[Effects] According to the present invention, when recording, the original sound signal is converted into a digital sound signal in a conversion range selected according to the amplitude of the original sound signal, and when playing back, the digital sound signal is converted into a digital sound signal by converting the amplitude of the digital sound signal. Since the signal is converted into an analog sound signal in a conversion range selected according to the signal, the amount of information to be stored is reduced, and a recording and playback device that can follow waveforms whose amplitude changes rapidly can be obtained.

Recording devices and playback devices equipped with conversion range selection means can automatically select a conversion range. Furthermore, since the conversion range can be automatically selected, there is no need to store conversion range information in the storage means, and the storage cost can be reduced.

In recording devices and playback devices provided with control data insertion means and control data extraction means, conversion range information can be stored separately from digital sound signals. Therefore, the configuration of the playback device can be particularly simplified.

Recording devices and playback devices equipped with signal compression means and signal expansion means can reduce the amount of information stored. In particular, tNli of each conversion range is I/2, I/4,...
. . , the signal compression means and the signal expansion means can be easily configured, and the overall configuration can be simplified by +11.

In recording devices and playback devices equipped with A/D conversion range changing means and D/A conversion range changing means, the maximum input range of the A/D conversion means and the maximum output range of the D/A conversion means are Since it is set optimally according to the amplitude, it is possible to record and play back high quality sound even if the amount of information to be stored is small.

Recording devices and playback devices equipped with gain changing means optimally set the gains of the variable input means and variable output means according to the amplitude of the sound signal, allowing recording and playback with high quality even if the amount of information to be stored is small. can do.

[Brief explanation of drawings]

1 and 2 are block diagrams showing an example of the eight-piece configuration of the present invention, FIG. 3 is a detailed explanatory diagram of the present invention, and FIG.
5 and 5 are block diagrams showing a first embodiment of the present invention, FIG. 6 is a block diagram specifically showing a part of the first embodiment, and FIGS. 7 and 8 are block diagrams showing a first embodiment of the present invention. FIGS. 9 and 10 are block diagrams showing a second embodiment of the invention, FIGS. 11 and 12 are block diagrams showing a third embodiment of the invention, and FIGS. 13 and 14 are block diagrams showing a fourth embodiment of the present invention, and FIGS. 15 and 1
FIG. 6 is a block diagram showing the fifth embodiment of the present invention.
7 and 18 are block diagrams showing the sixth embodiment of the present invention, FIG. 19 is an explanatory diagram showing the data structure of the data storage circuit in FIGS. 17 and 18, and FIG. 20 is a block diagram showing the sixth embodiment of the present invention. FIG. 6 is an explanatory diagram illustrating the principle of the sixth embodiment. SLI...First selection means TRI...1i1431 conversion means MRI...
...First storage means SL2 ...Second selection means TR2 ...Second conversion means MR2 ...Second storage means 9 SDI... ...first amplitude level detection means TSI・
...First conversion range selection means SD2...
-Second amplitude level detection means TS2...Second conversion range selection means CDI...Control data insertion means CDO...Control data extraction means ADI...
...First A/D conversion means SCM...Signal compression means DAI...First D/A conversion means SEP...
...Signal expansion means AC3...Second A/D conversion means ADTL...
- A/D conversion range changing means DA2...Second D/A conversion means DATL...D/A conversion range changing means AD3...Third A/D conversion Means GTI...
...First gain back means CHI...Variable input means DA3...Third D/A conversion means GT2...
...Second gain changing means CHO...-1'l
J variable output means 0 Fig. 5 223- Unexamined Japanese Patent Publication No. 3 72721 (21) Sign open Hei 3 /? /'lI (ii)

Claims (18)

[Claims] (1) A recording method in which an original sound signal is converted into a digital sound signal in a conversion range selected according to amplitude information of the original sound signal, and the converted digital sound signal is stored and recorded. (2) The recording method according to claim 1, wherein the digital sound signal is composed of a fixed number of bits. (3) a first selection means for selecting a conversion range according to the amplitude information of the original sound signal; and a first conversion means for converting the original sound signal into a digital sound signal in the conversion range selected by the first selection means. and a first storage means for storing the digital sound signal converted by the first conversion means. (4) The recording device according to claim 3, wherein the digital sound signal is composed of a fixed number of bits. (5) The first selection means includes a first selection means that detects an amplitude level according to amplitude information of the original sound signal.
and a first conversion range selection means for selecting a conversion range based on the amplitude level information detected by the first amplitude level detection means. recording device. (6) The recording device according to claim 3 or 4, wherein the first storage means stores conversion range information selected by the first selection means in addition to storing the digital sound signal. Device. (7) The first conversion means includes a first A/D conversion means for A/D converting the original sound signal, and an A/D conversion signal obtained by the first A/D conversion means. In the conversion range selected by the first selection means, A/
7. The recording apparatus according to claim 3, further comprising a signal compression means for converting the D-converted signal into a compressed signal having a smaller number of bits than the number of bits of the D-converted signal to obtain the digital sound signal. (8) The first conversion means includes a second A/D conversion means for A/D converting the original sound signal, and a second A/D conversion means for A/D converting the original sound signal; 7. The recording apparatus according to claim 3, further comprising A/D conversion range changing means for changing the maximum input range of the A/D conversion means. (9) The first conversion means includes a variable input means for obtaining a signal obtained by amplifying and/or attenuating the original sound signal, and a third A/D converting the signal obtained from the variable input means. Claim 3, 4, 5 or 6, comprising a conversion means and a first gain changing means for changing the gain of the variable input means in accordance with the conversion range selected by the first selection means. Recording device described in . (10) A reproduction method that reads a stored digital sound signal, converts the digital sound signal into an analog sound signal in a conversion range selected according to amplitude information of the digital sound signal, and reproduces the signal. (11) The reproduction method according to claim 10, wherein the digital sound signal is composed of a fixed number of bits. (12) a second storage means for storing a digital sound signal; a second selection means for selecting a conversion range according to the amplitude information of the digital sound signal; and a conversion range selected by the second selection means. A playback device comprising second conversion means for converting a digital sound signal into an analog sound signal. (13) The playback device according to claim 12, wherein the digital sound signal is composed of a fixed number of bits. (14) The second selection means includes a second amplitude level detection means for detecting an amplitude level according to the amplitude information of the digital sound signal, and a second amplitude level detection means for detecting the amplitude level according to the amplitude information of the digital sound signal. 14. The reproducing apparatus according to claim 12, further comprising second conversion range selection means for selecting a conversion range based on the conversion range. (15) The playback device according to claim 12 or 13, wherein the second storage means stores conversion range information selected by the second selection means in addition to storing the digital sound signal. . (16) The second conversion means is a signal that expands the digital sound signal into an expanded signal having a bit number greater than the number of bits of the digital sound signal in the conversion range selected by the second selection means. Claim 12, 13, 14 or 15, comprising an expansion means and a first D/A conversion means for D/A converting the expanded signal obtained by the signal expansion means.
The playback device described in . (17) The second conversion means includes a second D/A conversion means for D/A converting the digital sound signal; 16. The reproducing apparatus according to claim 12, further comprising D/A conversion range changing means for changing the maximum output range of the D/A converting means. (18) The second conversion means includes a third D/A conversion means for D/A converting the digital sound signal, and amplifies and/or attenuates the signal obtained by the third D/A conversion means. and second gain changing means that changes the gain of the variable output means in accordance with the conversion range selected by the second selection means. or 15
The playback device described in .