Abstract: In a time base corrector which converts incoming video signals to digital form and writes the digitized signals in sequentially enabled units of a main memory at a clocking rate varying generally in accordance with time base errors in the incoming signals, whereupon the signals temporarily stored in the memory are read out or fetched from the successive main memory units at a clocking rate which is standard at least at the beginning and end of each line interval and the read out signals are reconverted to analog form for eliminating the time base errors: the clocking rate for reading out the video signals from each of the main memory units is modulated during each line interval in accordance with velocity error information stored in a velocity error memory during writing of such video signals in the respective main memory unit.

Abstract: In a time base corrector which converts incoming video signals to digital form and writes the digitized signals in a memory at a clocking rate varying generally in accordance with time base errors in the incoming signals, whereupon the signals temporarily stored in the memory are read out or fetched therefrom at a standard clocking rate and reconverted to analog form for eliminating the time base errors; the memory is composed of a plurality of cyclically enabled memory units which each have a capacity to store an even number of line intervals of the video signals.

Abstract: In a time base corrector which converts incoming video signals to digital form and writes the digitized signals in a memory at a clocking rate varying in accordance with time base errors in the incoming signals, whereupon the signals temporarily stored in the memory are read out or fetched therefrom at a standard clocking rate and reconverted to analog form for eliminating the time base errors; the clocking rate for storing the digitized signals is determined by a write clock pulse signal generator having an automatic frequency control circuit in which the output frequency of a variable frequency oscillator is varied in dependence on the horizontal synchronizing signals in the incoming video signals, and an automatic phase control circuit in which the output of the variable frequency oscillator is phase shifted in dependence on the burst signals separated from the incoming video signals.

Abstract: In a time base corrector which converts incoming video signals to digital form and writes the digitized signals in sequentially enabled units of a main memory at a clocking rate varying generally in accordance with time base errors in the incoming signals, whereupon the signals temporarily stored in the memory are read out or fetched from the successive main memory units at a standard clocking rate and reconverted to analog form for eliminating the time base errors: a drop-out memory stores drop-out information in respect to drop-outs detected in the incoming video signals written in each of the main memory units; drop-outs are eliminated in the output from the time base corrector by rewriting, in each memory unit storing video signals having drop-out as indicated by the drop-out memory, video signals from another memory unit shown by the drop-out memory to be free of drop-out, with such rewriting being effected simultaneously with the read out of the video signals from such other memory unit; and upon the re

Abstract: A novel circuit is provided for controlling an alternating current supplied to a load which includes a variable impedance element in the form of a low emitter concentration transistor which is bidirectional, and which has a high gain. The impedance of the variable impedance element to the flow of current therethrough is substantially the same in either direction of current flow.