Time base corrector memory arrangement and memory control

A digital time base corrector for correcting time base errors in an unstabilized input composite color video signal by synchronizing the video signal with a studio reference signal, said time base corrector comprising:

• an analog to digital converter for converting said unstabilized input video signal into a series of digital data samples;
• write clock means for generating a plurality of input clock signals timed to the unstabilized input composite color video signal said input clock signals including an input conversion clock signal which is synchronous with the subcarrier of the unstabilized input video signal, an input horizontal clock pulse signal synchronous with the horizontal sync pulses of the unstabilized input video signal, and an input vertical clock pulse signal synchronous with the vertical sync pulses of the unstabilized input video signal;
• reference clock generating means for generating a plurality of reference clock signals tuned to the studio reference signal including a reference conversion clock signal which is synchronous with a subcarrier frequency of the studio reference signal, a reference horizontal clock pulse signal synchronous with horizontal sync pulses of the reference signal, and a reference vertical clock pulse signal synchronous with vertical sync pulses of the reference signal;
• timing corrector means for storing a plurality of said data samples in increments of at least one horizontal line;
• line writing means for writing said data samples into said timing corrector means at the rate of the reference clock signal for one horizontal video line beginning with an input horizontal clock pulse;
• line reading means for reading said data samples from said timing corrector means at the rate of the reference conversion clock signal for one horizontal video line beginning with a reference horizontal clock pulse;
• memory means for storing a plurality of horizontal video lines of data samples from said timing corrector means in increments of at least one video field;
• writing means for writing said horizontal lines of data samples into said memory means at the rate of said reference conversion clock signal for one video field beginning with an input vertical clock pulse and starting each horizontal line of data samples with an input reference horizontal clock pulse and stopping at the end of each line;
• reading means for reading said horizontal lines of data samples from said memory means at the rate of said reference conversion clock signal for one video field beginning with a reference vertical clock pulse and starting each horizontal line wiht a reference horizontal clock pulse and stopping at the end of each line;
• means for controllably delaying at least one signal of said input horizontal clock pulse signal, said reference horizontal clock pulse signal, said input vertical pulse signal, and said reference vertical clock pulse signal before it is applied to said memory means by said writing means or said reading means;
• a microprocessor based memory control for communicating control data to said means for delaying, said control data being indicative of the interval of delay desired for said at least one signal;
• and
• a digital to analog converter for converting said digital data samples read from said memory means into an analog composite color signal at the rate of said reference conversion clock signal video signal stabilized to said studio reference signal.