Mirror image generator for composite signals with chroma inversion

A method for time base inversion of chroma signals comprising the steps of:

• orthogonally modulating first and second color difference signals by first and second subcarriers such that either vector phase of said first and second subcarriers is deviated by an angle of 180.degree. from a standard phase defined by a burst signal;
• adding a plurality of luminance signals and a plurality of burst signals to the orthogonally modulated first and second color difference signals to obtain a first composite video signal;
• digitalizing said first composite video signal to obtain a second composite video signal;
• alternately writing said second composite video signal into first and second line memories in a predetermined write address sequence;
• and
• reading said alternately written second composite video signal from either of said first and second line memories in a non-write mode in a backward address sequence in comparison to the predetermined write address sequence for a time period during an active video signal until termination of said active video signal.

Time base inversion of chroma signals circuit, having first and second subcarriers wherein either of said first and second subcarriers have vector phases deviated by an angle of 180.degree. from a standard phase defined by a burst signal, comprising:

• means for orthogonally modulating said first and second color difference signals by first and second subcarriers to obtain orthogonal modulation signals;
• means for synthesizing said orthogonal modulation signals with said burst signal, a luminance signal, and a synchronizing signal to obtain a plurality of analog composite video signals;
• analog to digital converter means for converting said analog composite video signals to digital composite video signals;
• first switch means for supplying the output of said analog to digital converter means alternately to first and second one horizontal memories;
• reading said alternately supplied output from either of said first and second one horizontal memories in a backward sequence in comparison to the sequence the output was supplied to said memories;
• and
• digital to analog converter means for converting said digital composite video signals read out from said first and second one horizontal memories to analog composite video signals.

Time base inversion of chroma signals circuit comprising;

• analog to digital converter means for converting a plurality of composite video signals to digital composite video signals;
• first switch means for supplying an output of said analog to digital converter means alternately to first and second one horizontal memories;
• address control circuit means for supplying a plurality of write addresses to one of said first and second one horizontal memories selected by said first switch means in a predetermined writing address sequence and for supplying a plurality of read addresses to the other of said first and second one horizontal memories in an order of every two continuous addresses in a reverse address sequence in comparison to the predetermined writing address sequence;
• and
• reading out said supplied output from either of said first and second one horizontal memories in a reverse address sequence in comparison to the sequence the output was supplied to said memories for a sequence of every two continuous addresses and reading out said supplied output in the same sequence the output was supplied to the memories for every other two continuous addresses during a predetermined time period for an active video signal until termination of said active video signal.