Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P.
FSK decoder for caller ID
A device for processing a frequency shift keying (FSK) signal including caller ID information that comprises an analog-to-digital converter (ADC) converting the FSK signal into a digital FSK signal, the FSK signal further comprising a first frequency component, a second frequency component including the caller ID information, and a third frequency component, a first filter attenuating the first and third frequency components of the digital FSK signal to provide a first signal, a second filter attenuating the second frequency component of the digital FSK signal to provide a second signal, and a circuit calculating an energy level for each of the first and second signals, and selecting the first signal for output if the energy level of the first signal is smaller than that of the second signal, and selecting the digital FSK signal for output if the energy level of the first signal is greater than that of the second signal.
Winbond Electronics Corp.
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Yueh-Chang
Chen