| 摘要 |
A method for the recognition of video standards, in which an up/down counter is used to detect the polarity of synchronization pulses. Specifically, a value representing a duration is memorized, a counting value (Q) is produced, this value being incremented when a binary synchronization signal (INCI) is in one state and decremented when this signal is in the other state, a comparison is made of the value representing the duration and the counting value, at a given time, of the synchronization signal, and a signal representing the standard is produced as a function of the result of the comparison. This method is implemented by a circuit comprising a microcontroller, a detection circuit producing a pick-up control logic signal (CAP), a counter producing a counting value (Q) and a register to load the counting value when the pick-up control signal is active.
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