JPH08221100A - Recording method in recording/reproducing device using semiconductor memory - Google Patents

Abstract

PURPOSE: To make possible recording for many hours even in the case where the residual capacity of semiconductor memory in a recording/reproducing device which uses the semiconductor memory is small. CONSTITUTION: In the state where some digital signal data have been written into memory 5, high bit rate recording is made possible even when residual capacity is small by compressing the digital data having been written into memory 5 by means of a bit rate control circuit 4 and a memory control circuit 5 and thereby increasing the residual capacity of the memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for recording and reproducing an audio signal or the like using a semiconductor memory.

[0002]

2. Description of the Related Art When a voice signal is recorded by converting the voice signal into a digital signal and writing the digital signal in a semiconductor memory, the sampling frequency and the compression degree of the code determine how many memory bits are required per second. This is generally called a bit rate (bps). Normally, the bit rate written during recording is matched with the bit rate read during playback. For example, 1Mbit of memory is 10
Writing at Kbps will allow 100 seconds of recording and playback.

[0003]

If a voice signal of 50 seconds is recorded under the above conditions, the remaining memory is 5
If it becomes 00 Kbit and it tries to write to the memory even after this at 10 Kbps, a voice signal recording for another 50 seconds can be performed.

However, if it is desired to record for 100 seconds, it is necessary to reduce the sound quality and set the bit rate to 5 Kbps. As described above, in the conventional apparatus, when the remaining capacity of the memory is insufficient, the subsequent recording has no choice but to record with the sound quality lowered.

[0005]

In order to solve the above-mentioned problems, the present invention converts an input analog signal into digital signal data and writes it into a semiconductor memory, and converts digital signal data read from the memory into an analog signal. A recording / reproducing apparatus using a semiconductor memory for outputting the same, wherein the semiconductor memory that substantially reduces the bit rate of digital signal data already written in the semiconductor memory and increases the remaining capacity of the semiconductor memory is used. It is intended to provide a recording method of the recording / playback device.

[0006]

With the above structure, the bit rate of the digital signal data already written in the semiconductor memory is substantially reduced, and the remaining capacity of the semiconductor memory is increased. It is possible to record for a long time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 is an analog signal input terminal to which an analog signal such as a voice signal is input. An analog input signal from the analog signal input terminal 1 is first converted into a digital signal by the A / D conversion circuit 2. When converted into a digital signal in the A / D conversion circuit 2, the sampling frequency and the compression degree of the code are determined. Suppose here that the sampling frequency is 2.5 KHz
When compressed to 4 bits, the memory required for 1 second is 10 Kbits, that is, 10 Kbps.

The above signal processing control is performed by the bit rate control circuit 3, and the processed digital signal is written in the memory 5 with the RAM address and data controlled by the memory control circuit 4.

When reading data from the memory 5, the memory control circuit 4 specifies an address to read data from the memory 5, and the read data is decoded by the bit rate control circuit 3, and further, It is performed by the D / A conversion circuit 6 and is output as an analog signal from the analog signal output terminal 7.

Here, if the capacity of the memory 5 is 1 Mbit, writing at 10 Kbps enables writing for 100 seconds. With conventional equipment, 50
If you record for a second, the remaining memory capacity is 500K
It becomes bit, and if you try to write at 10 Kbps after this, you can record for 50 seconds later, but 100 more
In order to record seconds, it was necessary to reduce the sound quality and set the bit rate to 5 Kbps.

The apparatus of the present invention reduces the bit rate of already recorded data as needed to expand the remaining memory capacity. Specifically, 10K
The data for 50 seconds already recorded at bps is once read from the memory 5, the memory control circuit 4 performs compression, for example, to substantially reduce the data to 5 Kbps, and writes the data in the memory 5. Memory 5
The remaining capacity of is up to 3/4 (750 Kbit) from 1/2 (500 Kbit).
This makes it possible to write data to be written later at a high bit rate. Also, if you write at a low bit rate, you can record for a long time. Furthermore, it is useful to secure the remaining capacity of the memory when using the remaining memory to increase the bit rate and to record with high sound quality.

[0013]

As described above in detail, according to the present invention, an input analog signal is converted into digital signal data and written in a semiconductor memory, and digital signal data read out from the memory is converted into an analog signal. A recording and reproducing apparatus using a semiconductor memory for outputting, wherein the bit rate of the digital signal data already written in the semiconductor memory is substantially reduced to increase the remaining capacity of the semiconductor memory. Even if the digital signal data is written in the semiconductor memory and the remaining capacity is small, the remaining capacity of the semiconductor memory can be increased and the information to be written later can be written at a high bit rate. Also, if you write at a low bit rate, you can record for a longer time.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 analog signal input terminal 2 A / D conversion circuit 3 bit rate control circuit 4 memory control circuit 5 memory 6 D / A conversion circuit 7 analog signal output terminal

Claims (1)

[Claims] 1. A recording / reproducing apparatus using a semiconductor memory which converts an input analog signal into digital signal data and writes the same into a semiconductor memory, and converts the digital signal data read from the memory into an analog signal and outputs the analog signal. A recording method for a recording / reproducing apparatus using a semiconductor memory, wherein the bit rate of digital signal data already written in the semiconductor memory is substantially reduced to increase the remaining capacity of the semiconductor memory.