Judging circuit for standard or unstandard signals


Application Number: 00108896
Application Date: 2000.04.21
Publication Number: 1271232
Publication Date: 2000.10.25
Priority Information: 1999/4/21 JP 113837/99
International: H04N5/08;H04N9/455
Applicant(s) Name: Matsushita Electric Industrial Co., Ltd.
Address:
Inventor(s) Name: Fujita Nobuko;Kageyama Atsuhisa
Patent Agency Code: 72001
Patent Agent: jiang fuhou
Abstract In order that such a signal as is conventionally determined to be a standard signal in the unit of one field and determined to be a non-standard signal in the unit of a plurality of fields can be determined to be a non-standard signal, the following are provided: a clock generating circuit for generating a clock of a frequency being a constant multiple of the color carrier frequency; a register for setting the clock count of one field section of a standard signal; a vertical counter for counting the number of clocks generated by the clock generating circuit, and being reset when the clock count reaches the value of the register; and a flip-flop receiving the counter output as the input and using an external vertical synchronizing signal as a load hold pulse. Consequently, the output of the flip-flop represents the inter-field shift of the clock count represented by the external vertical synchronizing signal from the standard signal which shift is accumulated over a plurality of fields, so that even such a signal as is conventionally determined to be a standard signal in the unit of one field and determined to be a non-standard signal in the unit of a plurality of fields can be determined to be a non-standard signal.