| 摘要 |
A method for detecting SECAM-L signals is disclosed. First, a SECAM-L signal is received and demodulated into a demodulation signal. Then high frequency components of the demodulation signal are filtered out and a low frequency signal, including many sync pulses and many data pulses, is obtained. Next, the low frequency signal is inversion into an inversion signal, having many inversion sync pulses and many inversion data pulses. Afterwards a voltage level of the inversion signal is detected continuously whether it is a lowest level. After that, the lowest level is determined whether belonging to the inversion sync pulses when the voltage level of the inversion signal is the lowest level, and a detection signal is outputted. When the lowest level belongs to the inversion sync pulses, a voltage level of the detection signal is high, and the demodulation signal is an inversion SECAM-L demodulation signal. |
