9. Dual Tone Multi Frequency (DTMF) Generator
The H8/3877 Series on-chip dual tone multi frequency (DTMF) generator allows applications
to output DTMF signals.
Features: DTMF signals are used to access telephone exchange equipment and consist of
two sine waves expressed as a frequency matrix. The DTMF generator generates
frequency combinations corresponding to the numbers and symbols on a
• The DTMF frequencies are generated by dividing the oscillator clock (1.2 to
10 MHz in 400 kHz steps).
• Sine waves are output by a high-precision resistor ladder D/A converter,
allowing low distortion high stability waveforms to be acquired.
• Output of either row group/column group composite signals or independent
R1 (697 Hz)
R2 (770 Hz)
R3 (852 Hz)
R4 (941 Hz)