VOLUME CONTROL CIRCUIT BY SOFTWARE IN DIGITAL TELEPHONE

摘要

The circuit adjusts the volume through a key pad. The circuit includes: a microprocessor (10) for sensing a key pad (40); a ROM (20) for storing a program; a first latch (30) for setting the data of the microprocessor bit by bit; a buffer ((60) for reading the data of the first latch (30); a second latch (70) for setting the data of the buffer (60) bit by bit; a decoder (50) for decoding the address and read/write signals of the microprocessor; a first gain adjusting means for amplifying the signals in accordance with the gain of the second latch (70); and a second gain adjusting means for adjusting the gains in accordance with the difference between a voice input and the output signals of the first gain adjusting means.