JPS61199299A - Sound signal storing and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the cutting of starting of speech and to enable instantaneous reproduction and erasing by providing a circuit that converts inputted sound signals to digital signals and stores, and storing and reproducing the sound signals. CONSTITUTION:When sound-recording, clock signals are sent out from a controlling circuit 14 to an encoder 7, and synchronizing clock signals for writing and a writing mode setting signal are sent out. The sound signals inputted to the encoder 7 are converted to the digital signals and accumulated in a storage circuit 8. When reproducing, a switch 15 for reproduction is operated, and digital signals read from the circuit 8 are decoded to the sound signals by a decoder 9, amplified by an amplifier 10 and sent to a loud speaker 11. When erasing a specific part, the clock signal for writing that drives a specific address is sent from the circuit 14 to the circuit 8 by the command of an erasing switch 16, and the command is given from the data inputting section of the circuit 8 to the driven address to read the specific data. Accordingly, automatic sound recording is made possible, the structure becomes simple and an economical device can be realized.

Description

[Detailed description of the invention] (Industrial application field) The present invention is a storage and playback device that stores and plays back audio signals.

In particular, the present invention relates to an audio signal storage/reproduction device that digitizes and stores/reproduces an audio signal.

(Prior Art) Currently, as a means for storing and reproducing audio signals, it is common to use magnetic storage media such as magnetic tape, as typified by tape recorders. Magnetic storage media such as magnetic tapes are relatively inexpensive and allow long-time recording, so they are widely used.

(Problems to be Solved by the Invention) Incidentally, in an audio signal storage/reproduction device using a magnetic tape, storage/reproduction is performed while mechanically moving the magnetic tape as a storage medium.

It takes a start-up time to reach a normal recording state after starting recording and storing, and in order to play back the stored contents, it is necessary to rewind and play back the magnetic tape, which takes a certain amount of time. It has disadvantages such as.

Therefore, it is difficult to apply an audio signal storage/playback device using a magnetic tape when recording and playback must be repeated in a short period of time and when it is desired to perform recording and playback without worrying about operation time at all. Furthermore, if an audio signal storage/reproduction device using a magnetic tape is used to automatically record only the information desired to be recorded, the beginning of the 9th episode may be cut off.

A situation occurs in which recording of short syllables becomes impossible.

Due to these drawbacks, even though it is desired to use an audio signal recording/reproducing apparatus, there are cases in which the use of an audio signal recording/reproducing apparatus using magnetic tape has no choice but to be abandoned.

For example, in the case of baggage collection and delivery services, many parcel transport companies are currently operating parcel delivery services, and commercial radios are widely used in these transport vehicles. In most cases, transport vehicles carry one person, and the driver also serves as a person who collects and delivers luggage. From the time the transport vehicle leaves the collection/delivery center until it returns to the center after completing its work, communication with the Mobara Center is carried out via commercial radio. The use of commercial wireless has greatly contributed to improving business operations for these types of businesses. However, what is the problem in this case?

Because the driver also serves as the collector and delivery person, he often leaves the transport vehicle. As a result, the effectiveness of using professional wireless technology will be halved.

In addition, the usage efficiency of the commercial wireless system also decreases. At this time, if the transport vehicle is equipped with an audio signal recording and reproducing device, these inconveniences can be greatly alleviated. In other words, if voice information is sent to the center while the driver is away from the car, that information is automatically recorded and can be played back and received after the driver returns to the car. . In this case, the amount of audio information is generally relatively small, with an extremely large amount of information lasting about 5 seconds on average. As mentioned above, the use of a general tape recorder is not suitable for such applications.

SUMMARY OF THE INVENTION An object of the present invention is to provide an audio signal storage/reproduction device that can automatically store audio information that requires a relatively small amount of information to be transmitted each time, and can instantaneously reproduce audio information.

According to the invention, an encoder receives an audio signal and converts the audio signal into a digital signal.

and a storage circuit for storing this digital signal.

A decoder for demodulating the digital signal read from this storage circuit into an audio signal, and a decoder to which the audio signal is input, detects the level of this audio signal, and thereby sends out information on the presence or absence of the audio signal. and a control circuit for controlling the encoder, storage circuit, and decoder to store, reproduce, and erase the audio signal, and is provided with the presence/absence information from the sending means. , this control circuit is characterized in that an audio digital signal is stored in accordance with the presence/absence information from the above-mentioned sending means, and on the other hand, the above-mentioned storage port is controlled so that the above-mentioned stored isotal signal is read out. Thus, an audio signal storage/reproduction device is obtained.

(Example) The present invention will be explained below with reference to Examples.

FIG. 1 is a diagram showing an embodiment of an audio signal storage/reproduction device according to the present invention. Figure 1 shows only the functions necessary to explain the present invention. 2 Functions not directly related to the invention 1
For example, the power supply method, display function, etc. are omitted.

Referring to FIG. 1, 1 is an audio signal input terminal, 2 is a changeover switch for switching between the audio signal from input terminal 1 and the audio signal from microphone 3, and 4 is for amplifying the audio signal from microphone 3. 5 is an automatic gain control circuit (AGC).
6 is a sending means (hereinafter referred to as VOX) for sending out information on the presence or absence of an audio signal by detecting the level of the audio signal;
7 is an audio signal encoder, 8 is a storage circuit, 9 is a decoder, 1
0 is an amplifier for amplifying the decoded audio signal and exciting the speaker 11, 12 is a volume control volume for the speaker 11, and 13 is a clock signal generator.

14 is a control circuit, 15 is a reproduction switch for reproducing the audio signal, and 16 is an erasing switch for erasing the audio signal.

By switching the changeover switch 2, the audio signal input from the input terminal 1 or the microphone 3 passes through the switch 2 and the AGC circuit 5 and reaches point A in FIG.

The audio signal is divided into two at point A and input to the encoder 7 and VOX 6.

Here, an example of the circuit configuration of the VOX 6 will be described with reference to FIG. 2. Reference numeral 61 denotes an audio signal input terminal.

62, 63 and 65 are resistors, which together with the differential amplifier 64 constitute an audio signal amplifier.

66 is a decoupling capacitor which cuts the DC component and causes the transistor 70 to operate in class B mode.

Resistor 68 is used to bring the base of transistor 700 to ground potential. Therefore, transistor 70 is in an inactive state when there is no signal.

The audio signal input above a certain level is now connected to the transistor 70.
When input to the base of the transistor 70, the transistor 70 is turned on and forms a half-wave rectifier circuit. transistor 7
The output of 0 is smoothed by a capacitor 72 and input to a Schmitt circuit 73. The Schmitt circuit generates a voltage corresponding to the logic level '1' or '0# state. This output voltage is then sent to the control circuit 14 from the output terminal 74.

With reference to FIG. 3, the waveforms of the main parts of vOX shown in FIG. 2 will be explained. The signal applied to the input terminal 61 is an audio signal as shown in FIG. (Fig. 3(b)). The collector pressure of the transistor 70 is the voltage shown by a in FIG.

The reason why the voltage indicated by a is significantly different from the voltage across the resistor 71 is that the voltage across the capacitor 7
This is because the charging/discharging time constant of 2 changes. In such an audio signal l-pel detection circuit, ie, vOX, the charging time constant is generally as small as about 10 milliseconds or less, while the discharging time constant is set as large as about 100 v seconds. In the VOX shown in FIG. 2, the charging time constant is approximately determined by the product of resistor 71 and capacitor 72, and the discharging time constant is approximately determined by the product of resistor 69 and capacitor 72.

By the way, various systems have been implemented for the encoder shown in FIG. If sound quality is important for recording and playback, it is considered appropriate to use a PCM encoder (64 kilobits), but if a certain level of intelligibility is desired for practical purposes, an ADM encoder (16 kilobits) is considered appropriate. Alternatively, it is possible to lower the bit rate even further and use an 8 kilobit ADM encoder.

Considering economy, an 8 to 16 kilobit ADM system would be appropriate, since it reduces the capacity of the storage circuit 8 to reduce costs, and the encoder 7 and decoder 8 have simple configurations. Furthermore, a RAM may be used as the memory element 12 of the memory circuit 8. On the other hand, the decoder 9 is determined by the method of the encoder 7.

Encoder 7. The operation and non-operation of the memory circuit 8 and the decoder 9 can be controlled by drive pulses, that is, clock signals inputted from the control circuit 14, respectively.

From the control circuit 14 to the encoder 7. Memory circuit 8
By controlling the clock signals given to the decoder 9 and the decoder 9, it is possible to control functions such as recording, playback, and erasing of the audio signal storage and playback device.

With reference to FIGS. 1 and 2, the case of recording will first be described.

When the input of the audio signal is detected by the VOX 6, the output information from the output terminal 74 of the VOX 6 changes from low level (LOW) to high level (HIGH) as shown in FIG. 3(d). This output information is then sent to the control circuit 14. The control circuit 14 instantly determines whether or not this audio signal should be stored, based on predetermined conditions. For example, if the storage circuit 8 has a storage capacity of a predetermined value or more, it is determined that storage is possible, and if it is less than a predetermined value, it is determined that storage is not possible. When the control circuit 14 determines that the audio signal should be stored,
That is, in the recordable state, a clock signal is sent from the control circuit 14 to the encoder 7, and the encoder 7 becomes operational. At the same time, a write clock signal and a write mode setting signal synchronized with the clock signal to the encoder 7 are sent from the control circuit 14 to the storage circuit 8 . The audio signal input to the encoder 7 is here converted into a digital signal and stored in a storage circuit. That is, recording is performed. When audio signals are input intermittently, the above-described process is repeated. In this way, the necessary audio signals can be automatically recorded.

Next, the case of reproduction will be explained.

By the way, the presence or absence of audio information stored in the storage circuit 8, that is, whether or not audio information is stored in the storage circuit 8 is determined by the control circuit 14.

Therefore, by connecting a display device to the control @@14 shown in Figure 1, it is possible to display the presence or absence of audio information, making it easy to reproduce the required audio information as needed. can.

When performing reproduction, the reproduction switch 15 is operated.

Then, a state change signal is output from the regeneration switch 15, and this state change signal is sent to the control circuit 14. The control circuit 14 recognizes that it has received a reproduction command based on the state change signal, and sends a read mode setting signal and a read clock signal to the memory circuit 8, and at the same time sends a read clock signal to the decoder 9 to the memory circuit 8. A clock signal synchronized with the signal is sent out. On the other hand, when the clock signal is being sent to the memory circuit 8 and decoder 9,
No clock signal is sent to the encoder 7. The digital signal read out from the storage circuit 8 is decoded into an audio signal by a decoder 9, amplified by an amplifier 10, and sent to a speaker 11. The volume of speaker 11 is for volume adjustment g IJum 12
All you have to do is operate.

Furthermore, the case of erasing will be explained.

When the erase switch 16 is operated, the control circuit 14 recognizes that it has received an erase command. Next, the control circuit 14
determines whether the content to be erased is all of the information stored in the storage circuit 8 or a specific portion.

When erasing the entire information stored in the memory circuit 8, a method such as turning off the power supply (not shown) to the memory circuit 8 and not sending a clock signal to the decoder 9 are used.

On the other hand, when erasing a specific part, the erasing switch 16 has a function of instructing the control circuit 14 to erase the specific part stored in the memory circuit 8. In response to an instruction from the switch 16, a write clock signal for driving a specific address is sent from the control circuit 14 to the memory circuit 8. At the same time, the data input section of the memory circuit 8 instructs the memory circuit 8 to read specific data at a low level or a high level into the driven address.

At this time, no clock signal is sent to the encoder 7 and decoder 9. Erasing a specific portion is performed as described above.

(Effects of the Invention) As explained above, (1) the audio signal storage and playback device according to the present invention is capable of automatic recording; ■Be able to almost ignore truncations at the beginning of speech. ■It has the advantage of being able to perform instantaneous playback and erasure operations.

It has the following advantages: (1) There are no mechanical parts; and (2) the decoder, memory elements, etc. can be constructed economically using LSIs for digital circuits, which are becoming cheaper.

Therefore, it is effective to use the audio signal storage and playback device according to the present invention in cases where a normal tape recorder cannot be used, and furthermore, in cases where a normal tape recorder cannot be used. It can be expected to be used in many fields.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic diagram showing an embodiment of the audio signal storage/reproduction device according to the present invention, and FIG. 2 is a circuit diagram showing an embodiment of the VOX shown in FIG. FIG. 3 is a diagram showing voltage waveforms of main parts of VOX shown in FIG. 2. 1... Audio signal input terminal, 2... Selector switch, 3
...Microphone, 4...Amplifier, 5...AGC circuit,
6...VOX. 7... Encoder, 8... Memory circuit, 9... Decoder,
DESCRIPTION OF SYMBOLS 10... Amplifier, 11... Speaker, 12... Volume adjustment gium, 13... Clock signal generator,
14... Control circuit, 15... Regeneration switch, 16
... Erasing switch, 61... Audio signal input terminal,
62, 63, 65° 67.68, 69.71...Resistor, 64...Differential amplifier, 66...Decoupling capacitor, 70...Transistor, 72...Smoothing capacitor, 73... ...Schmitt circuit, 74...output terminal.

Claims (1)

[Claims] 1. An audio signal is input, an encoder for converting the audio signal into a digital signal, a storage circuit for storing the digital signal, and demodulating the digital signal read from the storage circuit into an audio signal. a decoder for inputting the audio signal, a transmitting means for detecting the level of the audio signal and thereby transmitting information on the presence or absence of the audio signal; and a decoder for receiving the audio signal; a control circuit for controlling the encoder, storage circuit and decoder to store, reproduce and erase the signal, the control circuit confirming the presence of the audio signal by the presence/absence information from the sending means; Then, the storage circuit is controlled to write mode, and the digital signal is stored in the storage circuit. On the other hand, when reproducing the audio signal written in the storage circuit, the control circuit controls the storage circuit to write. An audio signal storage/reproduction device characterized in that the stored digital signal is read out by controlling the device to read mode.