SECAM-L detector and video broadcast system having the same
First Claim
1. A method for detecting SECAM-L signals, comprising:
- receiving a video signal and demodulating the video signal into a demodulation signal comprising a plurality of sync pluses and data pulses;
filtering high-frequency (HF) components of the demodulation signal;
inverting the demodulation signal into an inversion signal, the inversion signal comprising a plurality of inversion sync pulses and inversion data pulses in correspondence to the demodulation signal;
continuously detecting whether a voltage level of the inversion signal is a lowest level; and
when the voltage level of the inversion signal is the lowest level, determining whether the lowest level belongs to the inversion sync pulses and then sending out a detection signal;
wherein when the lowest level belongs to the inversion sync pulses, a voltage level of the detection signal is a high level, the demodulation signal is an inversion SECAM-L demodulation signal.
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Accused Products
Abstract
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.
8 Citations
19 Claims
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1. A method for detecting SECAM-L signals, comprising:
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receiving a video signal and demodulating the video signal into a demodulation signal comprising a plurality of sync pluses and data pulses; filtering high-frequency (HF) components of the demodulation signal; inverting the demodulation signal into an inversion signal, the inversion signal comprising a plurality of inversion sync pulses and inversion data pulses in correspondence to the demodulation signal; continuously detecting whether a voltage level of the inversion signal is a lowest level; and when the voltage level of the inversion signal is the lowest level, determining whether the lowest level belongs to the inversion sync pulses and then sending out a detection signal; wherein when the lowest level belongs to the inversion sync pulses, a voltage level of the detection signal is a high level, the demodulation signal is an inversion SECAM-L demodulation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for detecting SECAM-L signals, comprising:
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demodulating a video signal into a demodulation signal; and detecting whether a voltage level of an inversion signal of the demodulation signal is a lowest level to determine whether the demodulation signal is an inversion SECAM-L demodulation signal. - View Dependent Claims (10, 11)
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12. A video broadcast system, comprising:
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a tuner, for demodulating a video signal into a demodulation signal comprising a plurality of sync pulses and data pulses; and a SECAM-L detector, for detecting whether a voltage level of an inversion signal of the demodulation signal is a lowest level to determine whether the demodulation signal is an inversion SECAM-L demodulation signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification