Digital arrangement for detecting a correct television synchronization signal output useful in a signal seeking tuning system

A detector for determining the correctness of a television synchronization signal including synchronization pulses for use in a signal seeking tuning system, comprising:

• first threshold comparator means for generating first output pulses when said synchronization signal has an amplitude component below a first predetermined threshold below the maximum excursion of said synchronization pulses;
• second threshold comparator means for generating second output pulses when said synchronization signal has an amplitude component above a second predetermined threshold above the minimum excursion of said synchronization pulses;
• first counter means for counting the number of said first output pulses during a measurement interval;
• second counter means for counting the number of said second output pulses during said measurement interval;
• first count comparator means for determining when said count counted by said first counter means is within predetermined count limits;
• second count comparator means for determining when said count counted by said second counter means is within said predetermined count limits;
• and
• error determining means for generating an error signal when one of said predetermined count limits is exceeded.