| 摘要 |
<p>Provided is a pulse modulation method capable of reducing a transmission period TD of a code formed by a plurality of bit data and surely demodulating the bit data even if a jitter is generated in the pulse by the transmission environment. A code formed by 4N (N is a positive integer) bit data is divided into a unit formed by 2-bit data. One of the time widths 0, ?t, 2?t, 3?t is added to a fixed pause period tm to obtain four types of pulse pause interval Tr which are set by being correlated to four unit values so as to generate a code modulated signal subjected to pulse phase modulation by the unit value. The code modulation signal has a fixed pause period tm of the time interval almost identical to at least the fixed pulse width tw. Between each pulse pause interval Tr, there exists a time difference of an adjustment time width ?t set to a value not smaller than 1/2 of the fixed pulse width tw and smaller than the fixed pulse width tw. Accordingly, even if the pulse rise and fall positions are changed, no demodulation error is generated and the transmission period TD of the entire code is reduced.</p> |
