PCM Tone signal generator

A digital tone signal generator for supplying binary signals in a sequence representing a pulse code modulation (PCM) tone to a plurality of time division multiplexed TDM channels in an associated switching facility having an operating format defined by a frame signal and a clock signal consisting of 320 pulses in the period of the frame signal, the generator comprising:

• a clock generator responsive to the pulses of the clock signal and to the frame signal for generating a plurality of clock pulses during the period of the frame signal, said plurality of clock pulses corresponding in number to 320 or an integer submultiple of same, plus or minus one;
• a counter for sequentially generating a series of addresses in response to the clock pulses from the clock pulse generator, the number of addresses in said series corresponding to the number of binary signals in said sequence;
• and
• a memory having said binary signals stored at address accessible locations therein, the memory unit being responsive to the addresses from the counter to read out the stored binary signals in the order of the sequence progressively with each occurrence of a given TDM channel whereby different ones of a plurality of analog lines associated with a frame of said operating format may each receive a different phase of the tone being generated.