M751
M751 is Touch Tong Generator manufactured by SGS.
f f
M 751 tOS/MOS INTEGRATED CIRCUIT f----------------------------------------------------------------
PRELIMINARY DATA
~OUCH TONE GENERATOR f' 2.5 to 5V SUPPLY
:. INTERNAL PULL-UP WITH DIODE PROTECTION ON ALL INPUTS ,. ON CHIP CRYSTAL CONTROLLED OSCILLATOR: 4.433619 MHz
- INTERNAL CAPACITORS FOR THE CRYSTAL OSCILLATOR
- LOW HARMONIC DISTORTION
- HIGH BAND TONES PRE-EMPHASIS
The M751 can provide all tone frequency pairs required for the Touch Tone Dialling System. The output :frequencies are obtained from an internal crystal controlled oscillator whose frequency is reduced in two ,independent programmable counters. The dividing ratio is controlled by the selected key. The circuit is...
