Dtmf and high-lowtone generating circuit

The circuit generates dual tone multiple frequency (DTMF) and high/ low tone signal suitable to AMPs system using frequency synthesis method. The circuit includes a logic circuit (10) for generating low frequency selecting decode signal (LG0-LG3) for decoding digital data for designating frequency and for selecting low frequency group and low tone signal, high frequency selecting decode signal (HG0-HG3), and low frequency and high frequency enable signal, a low frequency divider (12) for generating a first clock pulse having frequency multiple times of frequency selected by decode signal, and a high frequency divider (14) for generating a second clock pulse.