Phase shifting apparatus

Claim 1

A controlled phase shifter having a timing signal input and a control signal input, said timing signal input adapted to receive a periodic timing signal of a selected period, said voltage controlled phase shifter comprising: a period timing means having a period timing means output, said period timing means being capable of providing at said period timing means output, in each said selected period and in response to said periodic timing signal, a periodic phase delay signal each of which is a single-valued function of phase in its corresponding said selected period for a significant portion of that said corresponding selected period; a comparator means having first and second comparison inputs and a comparator means output, said first comparison input connected to said period timing means output and said second comparison input serving as said control signal input, said comparator means being capable of providing a comparator means output signal level shift at said comparator means output thereof when said periodic phase delay signal sufficiently exceeds a control signal applied to said control signal input; and a duty cycle determination means having a duty cycle determination means input and a duty cycle determination means output and a duty cycle determination means input connected to said comparator means output, said duty cycle determination means being capable of providing and occurrence indication, at said duty cycle determination means output, that a said comparator means output signal level shift has occurred and being capable of providing a determination indication when a selected fraction of a said selected period has elapsed after each occurrence of said occurrence indication.