Memory-type sync generator with reduced memory requirements

Claim 1

A television synchronizing signal generator comprising: first memory means for storing information relating to the magnitude of at least one component of a composite synchronizing signal at each of a predetermined plurality of sample points in each television frame; clock signal generating means coupled with said memory means for generating signals for recurrently addressing said memory means for reading said information from said memory sample by sample for generating said component signal; the improvement comprising; controllable rate controlling means coupled with said clock signal generating means and with said first memory means for controlling the instantaneous rate to a value other than zero at which said first memory means is addressed for controllably changing the rate at which said samples relating to the magnitude of at least one component of a composite sync signal are generated; and second memory means coextensive with said first memory means and coupled with said first memory means for being addressed simultaneously therewith, said second memory means being adapted for being loaded with information relating to the rate at which said first memory means is addressed, said second memory means being coupled to a rate control input terminal of said controllable rate controlling means for changing the rate of addressing of said first memory means during each field, said controllable rate controlling means comprising a controllable counter, said controllable counter comprising, a fixed counter coupled to said clock signal generating means for generating a divided clock signal; and controllable multiplexing means coupled to said clock signal generating means and to said fixed counter for coupling to an output terminal thereof one of said divided clock signal and said clock signal in response to a control input, said control input being coupled to said second memory means for controlling said rate.