| 摘要 |
PULSE WIDTH DECODER FOR DOUBLE FREQUENCY ENCODED SERIAL DATA Disclosed is a pulse width decoder which receives a double frequency modulated (DFM) waveform and recovers therefrom the contained NRZ-L data and clock information. Basically, the decoder looks for long and short pulses in the DFM waveform. A long pulse is decoded as a "0", while a pair of short, opposite polarity pulses are decoded as a "1". In addition, in order to allow for pulse shortening in the DFM waveform, a short pulse followed by a long pulse is interpreted as a "1". The clock signal is primarily derived from two delayed versions of the DFM waveform to create one clock edge every bit time. |
