JPH0294199A - Sound recording and reproducing device - Google Patents

Abstract

PURPOSE:To effectively use the capacity of a semiconductor memory by transferring signals stored in a memory circuit for memory recording to a memory section before the sound recording starting position of the semiconductor memory circuit for storage when the sound recording state is canceled by switching an operation switch for stopping. CONSTITUTION:This sound recording and reproducing device is constituted in such a way that, when an operation switch 16 for sound recording is pressed and closes, signal writing operations are started to a RAM 13 and, at the same time, writing operations to part of a memory section for memory recording are stopped. Moreover, when an operation switch 18 for stopping is pressed and closed in such state, the signal writing operations to the RAM 13 are stopped and, at the same time, signals stored in the memory section for memory recording are transferred to and written in a memory section before the sound recording starting position of the RAM 13. Therefore, futile sound recording can be reduced and the capacity of a semiconductor memory can be used effectively.

Description

[Detailed Description of the Invention] Kui> Industrial Application Field The present invention converts a recording signal obtained from a microphone into a digital signal and stores it in a semiconductor memory, and also converts the signal stored in the semiconductor memory during playback operation. The present invention relates to an audio recording and reproducing device that converts the audio into an analog signal after reading the audio and outputs the audio through a speaker.

(B) Conventional Technology Cassette tape recorders, which use magnetic tape called cassette tape, have become popular as devices for recording and playing back audio. Devices that use magnetic tape as a means of recording audio signals, such as the cassette-type cheap player, have the advantage of being able to record for long periods of time, but it is difficult to miniaturize the device. In addition, since it requires a mechanism to drive the magnetic tape, there is a problem in that the failure rate is high. As an improved device in this respect, the audio signal is converted into a digital signal and stored in a semiconductor memory, and during playback operation, the signal stored in the semiconductor memory is read out, converted into an analog signal, and then emitted through a speaker. A technology has been developed to do this, and an example of such technology is the
There is one disclosed in Japanese Patent No.-22800.

(C) Problems to be Solved by the Invention The technology disclosed in the above-mentioned publication uses a semiconductor memory as a means to record audio signals, which eliminates the need for a drive mechanism like that of a tape recorder, and reduces the size of the device. However, with this technology for recording audio into semiconductor memory, it is impossible to perform long-term recording operations due to limitations imposed by the capacity of the memory. There is a problem.The present invention aims to provide a voice recording/playback device that can reduce wasteful recording and effectively use the capacity of a semiconductor memory.

(d) Means for Solving the Problems The present invention provides an ADPCM analysis and synthesis circuit that performs voice analysis and voice synthesis using the ADPCM method during recording and playback operations;
a control circuit that controls writing of digital signals output from the ADPCM analysis and synthesis circuit into the semiconductor memory circuit and reading of signals stored in the semiconductor memory circuit; a recording operation switch that starts the operation of writing a signal to the memory circuit; a reproduction operation switch that is switched during the playback operation and also starts the readout operation of the signal stored in the semiconductor memory circuit; and a playback operation switch that is switched during the memory recording operation. The recording device is comprised of a memo-recording operating switch which is operated by a user, and a memory recording memory circuit which stores a signal obtained from a microphone as a digital signal for a predetermined period of time in a memory recording state by switching the memory recording operating switch.

(E) Function The present invention starts the writing operation of a signal to the semiconductor memory circuit when the recording operation switch is switched in the memory recording state, and also starts the writing operation to the memory recording memory circuit which is in the storage operation state. When the recording state is canceled by switching the stop operation switch, the signal stored in the memo no recording memory circuit is transferred and stored in the oil memory section at the recording start position of the semiconductor memory circuit. It is something.

(F) Embodiment The circuit shown in FIG. 1 is an embodiment of the present invention, and FIG. 2 is a diagram for explaining the present invention in detail.

In the illustrated circuit, <1> is a microphone that converts an acoustic signal into an electrical signal, (2> is the microphone <
1) is input with a recording signal converted into an electrical signal and amplifies the signal; (3) is unnecessary as the recording signal amplified by the recording amplifier circuit (2) is input. This is a low-pass filter that blocks high-frequency signals. (4) is the low pass filter (3)
A converts the analog signal passed through into a digital signal
-D converter (5) is an ADPC that performs digital processing using a method called ADPCM, that is, adaptive differential pulse code modulation.
M analysis and synthesis circuit (6) is a DA converter that converts the digital signal processed by the ADPCM analysis and synthesis circuit 5) into an analog signal; <7> is the DA converter (6);
) inputs the playback signal converted into an analog signal and also cuts off unnecessary high-frequency signals through a low-pass filter, and (8) inputs the playback signal that has passed through the low-pass filter (7) and amplifies the signal. The reproducing amplifier circuit <9) is a speaker to which the signal amplified by the reproducing amplifier circuit <8) is applied and emits the signal. (10) is the ADPCM analysis and synthesis circuit (5
), (11) a control unit that controls the analysis operation and synthesis operation of
is a data I10 buffer circuit that controls signal input/output operations between an external circuit and the ADPCM analysis/synthesis circuit (5) and control section (10). In such a circuit,
A-D converter (4), ADPCM analysis and synthesis circuit (5),
D-A converter <6), control section (10) and data I10
The buffer circuit (11) constitutes the audio processing circuit (12), but such a circuit may be, for example, LSI'MSM6258J manufactured by Oki Electric Industry Co., Ltd., and its details will be omitted. do. (13) is a data I10 buffer circuit (12) constituting the audio processing circuit (12).
11) A RAM which is a semiconductor memory that stores digital signals output from the RAM (14).
3) an address control circuit that controls the write operation and read operation of signals to the audio processing circuit (12);
, a control circuit that controls the operations of the RAM (13) and the address control circuit (14). (16) is the RAM (1
3) is a recording operation switch that is pressed and closed when storing an audio signal; (17) is a reproduction operation switch that is suppressed and opened when reading and reproducing a signal that has been completely stored in the RAM (13); , (18) is a stop operation switch that is suppressed and opened during a stop operation, and (19) is a memory recording operation switch that is suppressed and opened during a memory recording operation. When the recording mode is activated, the microphone <1> is placed in the memory recording memory section provided in RAM (13).
The resulting audio signal is stored for a predetermined period of time.

In such a state, when the recording operation switch (16) is suppressed and opened, the writing operation of the signal to the RAM (13>) is started, and at the same time, the writing operation to the memory section for recording memory is stopped. In addition, when in such a state, the stop operation switch (
18> is suppressed, the writing operation of the signal to the RAM (13) is stopped, and the signal stored in the memory recording memory section is transferred to the RAM (13).
The data is transferred and written to the memory section before the recording start position.

The present invention is constructed as described above, and the operation of this circuit will now be described. If the sampling frequency in the audio processing circuit (12) is 8 KHz and the number of quantization bits is 4, the bit rate is 32 bits/second, and R
If the capacity of AM<13) is 4 Mbits, it can be stored for about 128 seconds. In this example, A
The analysis and synthesis processing operation by the DPCM analysis and synthesis circuit (5) and the writing operation to the RAM (13) accompanying the processing are as follows.
This is done in 1 second intervals. That is, the audio processing circuit (1
The analysis and synthesis operation by the ADPCM analysis and synthesis circuit (5) is started by the start signal output from the control unit (10) incorporated in the control unit (10) incorporated in the control unit (10) after one second.
) The analysis and synthesis operation is stopped by the stop signal output from the terminal. When a signal is written to the RAM (13), that is, during a recording operation, the signal analyzed and processed by the ADPCM analysis and synthesis circuit (5) during the one second period is output to the RAM (13) through the data I10 buffer circuit (11). At the same time, the address is specified and written into the RAM (13) by the control operation of the address control circuit (14).Furthermore, during the readout operation of the signal from the RAM (13), that is, during the reproduction operation, the one second The signal synthesized by the ADPCM analysis and synthesis circuit (5>) is input to the D-A converter (6) and converted into an analog signal.Then, the write operation is performed by the suppression operation of the memory recording operation switch 19). For example, 4 seconds of audio signals are written one after another in the recording memory section, and when the recording operation is started by the suppression operation of the recording operation switch (16), the data is stored in the RAM (13). The write operation is configured such that a memory section in which a 4-second signal is written is left at the beginning, and is performed from the next memory section.

As described above, the control operation of the RAM (13) by the audio processing circuit (12) and the address control circuit (14) is performed. Next, each operation in this embodiment will be explained. First, normal recording operation will be explained. When the recording operation is performed, power is supplied to the recording amplifier circuit (2), and the recording operation switch (16) is suppressed and opened, and the control circuit <15> is turned on.
) starts the control operation for recording. The recording signal converted into an electrical signal by the microphone (1) is input to the recording amplifier circuit (2), amplified, and then input to the audio processing circuit (12) through the low-pass filter (3).The audio processing The recording signal inputted to the circuit (12) is converted into a digital signal by the A-D converter (4), and the analysis operation by the ADPCM analysis and synthesis circuit (5) is repeatedly performed in 1-second intervals as described above. The signal analyzed and processed by the ADPCM analysis and synthesis circuit (5) is sent to the data I10 buffer circuit (
11) to RAM (13) and is output to RAM (13) by the control operation of the address control circuit (14).
) is written. While the recording operation is being performed, the above-mentioned analysis operation by the ADPCM analysis and synthesis circuit (5) and writing operation to the RAM (13) are repeated until the stop operation is performed or the capacity of the RAM (13) is exhausted. It will be done.

Although the normal recording operation is performed as described above, the reproduction operation will be explained next. When the playback operation is performed, power is supplied to the playback amplifier circuit 8〉 and the playback operation switch ＜
17) is pressed open, and the control circuit (15>) starts a control operation for regeneration.

The signals stored in the RAM 3) are read out by the control operation of the address control circuit (14) and are input to the ADPCM analysis and synthesis circuit <5> through the data I10 buffer circuit (11). The digital signal input to the ADPCM analysis and synthesis circuit (5) is
After being synthesized by the CM analysis/synthesis circuit (5) in 1-second intervals, the signals are applied to the DA converter (6) and converted into analog signals.

The signal converted into an analog signal by the D-A converter (6>) is input to the reproduction amplifier circuit <8> through the low-pass filter <7>, where it is amplified and then sent to the speaker (
9). Then, while the playback operation is being performed, the readout operation from the RAM (13) and the AD
The synthesis operation by the PCM analysis and synthesis circuit (5) is repeated until a stop operation is performed or until there are no more signals written in the RAM (13).

The normal recording and reproducing operations are performed as described above, but next, the memory recording operation will be explained. When the memory recording operation is performed, power is supplied to the recording amplifier circuit (2), the memory recording operation switch (19) is suppressed, and the control circuit (15) starts controlling the memory recording. The recording signal converted into an electrical signal by the microphone (1) is amplified by the recording amplifier circuit (2) as described above, and then sent to the audio processing circuit (1).
2) and undergoes audio processing. The audio processing circuit (
The signal digitally processed by 12) is stored in RAM (
13), but this write operation is shown in Figure 2 (Δ).
This is done as shown below. That is, the signals are written one after another into the memory recording memory unit (20) provided in the RAM (13), but the signals written in the memory unit (20) are read as follows after a predetermined time, that is, after 4 seconds. It will be erased by writing the signal.

Therefore, new signals for 4 seconds are stored one after another in the memory recording memory section (20). When the recording operation switch (16) is pressed and closed in this state, the memory recording is started. The write operation to the memo portion <20) is stopped, and at the same time the write operation to other memory portions in the RAM (13) is performed. The point (T, ) of the memory recording memo portion (20) shown in FIG. for,(
The 4-second signal of a) (b) (c>(d)) is stored in the memory.Then, the audio signal accompanying the recording operation is stored in the RAM.
The write operation to (13) can be started from point (T,) as shown in FIG. 2(A).

In other words, the write operation to RAM (13) leaves the memory section (21) for 4 seconds at the beginning and writes the next memory section (21).
22), (e) (f) (g) (h) (i)
It is written as... The recording operation in the memory recording operation state is started in this way, but when the stop operation switch <18) is pressed and closed in this state, the writing operation of the audio signal to the RAM <13) is started. When it stops, the memory recording memory section (20
) is transferred and written to the memory section (21). FIG. 2(B) shows a state in which such a transfer write operation has been performed, and the memory section (21) contains the signal stored in the memory recording memory section (20>, that is, (8) (b)). (c) and (d) are written as shown in the figure.
) When playing back the signal stored in the memory section (21)
, (22)...... the signal stored in (
It will be played continuously as follows: a) (b) (c) (d) (e) (f>... ) is suppressed and the signal for 4 seconds before the recording operation starts is RA.
Since the conversation will be stored in RAM (13), even if the user performs a recording operation after having a conversation that he or she wants to record, he or she can still have that conversation stored in RAM (13).

Note that the recording and playback time can be increased by increasing the capacity of the RAM (1, 3) or by setting the thumbling frequency low. Furthermore, if the RAM (13) is built into a container called an IC card and the IC card (RAM 13) is made replaceable, it can be used as a recording means in place of a tape recorder even if the RAM (13) has a small capacity. You can. Although the analysis and synthesis time during recording and playback operations is set to 1 second, the time is not limited. Furthermore, although the time to be stored in the memory recording memory section (20) is set to 4 seconds, the time is not limited to 4 seconds.
Although it is provided in M (13), it can also be provided separately as a memory recording memory circuit.

(G) Effects of the Invention According to the present invention, when the recording operation switch is switched in the memory recording state, the writing operation of a signal to the semiconductor memory circuit is started, and the writing operation to the memory recording memory circuit which is in the storage operation state is started. When the operation is stopped and the recording state is canceled by switching the stop operation switch, the signal stored in the memo no recording memory circuit is transferred and stored in the memory section in front of the recording start position of the semiconductor memory circuit. By doing this, it is possible to record the signal before the recording operation starts by switching the recording operation switch, so that only the necessary information can be selected. This is extremely effective in effectively using the capacity of semiconductor memory.

[Brief explanation of the drawing]

The circuit shown in FIG. 1 is an embodiment of the present invention, and FIG.
>(B) is a diagram for explaining the present invention in detail. Explanation of main drawing numbers (1)... Microphone, (2)... Recording amplifier circuit, (5)... ADPCM analysis and synthesis circuit, (
8)...Reproduction amplifier circuit, 9)...Speaker (12>...Audio processing circuit, (13)...R
AM, (14)...address control circuit, <15
)...control circuit.

Claims (1)

[Claims] (1) Convert the recording signal obtained from the microphone into a digital signal and store it in a semiconductor memory circuit, and during playback operation, read out the signal stored in the semiconductor memory circuit, convert it into an analog signal, and emit it through a speaker. In a voice recording and playback device configured to produce sound, an ADPCM analysis and synthesis circuit that performs voice analysis and voice synthesis using an ADPCM method during recording and playback operations;
a control circuit that controls writing of digital signals output from the analysis and synthesis circuit to the semiconductor memory circuit and reading of signals stored in the semiconductor memory circuit; and a control circuit that is switched during a recording operation and sent to the semiconductor memory circuit. a recording operation switch that starts the writing operation of the signal; a playback operation switch that is switched during the playback operation and also starts the readout operation of the signal stored in the semiconductor memory circuit; and a memory recording switch that is switched during the memory recording operation. and a memory circuit for storing the signal obtained from the microphone as a digital signal for a predetermined period of time when in the memory recording state by switching the memory recording operation switch. When the recording operation switch is switched, the writing operation of the signal to the semiconductor memory circuit is started and the writing operation to the memory recording memory circuit is stopped, and when the recording state is canceled by switching the stop operation switch. A voice recording/playback device characterized in that the signal stored in the memory circuit for recording memory is transferred and stored in a memory section in front of the recording start position of the semiconductor memory circuit.