| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve reliability by temporarily converting an analog signal into a digital by an A/D converter and holding it in a data register to simplify write circuits and to make the variation of memory cells small. SOLUTION: An inputted analog voice signal is converted into a digital signal in a prescribed cycle by a first AD converter 1 to be digitally held in a data register. The data are compressed by an ADPCM(adaptive differential pulse code modulation) encoder 2 to be transmitted to a read-write control circuit 3. At this time, the compressed data are converted into an analog signal again in the second DA converter 4 of the control circuit to be written in an EEPROM 6 while specifying an address by an address generating circuit 10. On the other hand, at the time of a reproducing, the analog signal is read out from the EEPROM 6 by a second AD converter 5 to be subjected to a digital conversion and is decoded by an ADPCM decoder 7 and to be converted into an analog voice signal by a first DA converter 8 to be emitted as a sound. Thus, write circuits are simplified and the variation of memory cells is made small to improve reliability of a data holding.</p> |
