| 摘要 |
A wireless digital transmission and receiving method combines phase reversal keying with pulse position modulation. Modulation of a transmitted signal implements pulses that are of extremely short duration to indicate ones and zeros. These pulses can be as narrow as one cycle of the carrier frequency. As such, they often appear as missing cycles or pulses in a sequence of carrier cycles. The method synthesizes a sideband with no carrier or other sidebands from the carrier of an input signal. This synthesized sideband is represented by a broad sinx/x spectrum with a principal power peak at the modulated frequency and numerous weaker peaks of varying frequencies and peak levels. The time duration of these smaller peaks is such that they have negligible mean power levels. Thus, the synthesized signal can withstand the degradation caused by multipath interference and fading. The weaker peaks also do not cause measurable interference with other communications devices. The smaller peaks can have amplitudes far below the noise level of the system. Hence, the smaller peaks are not a necessary or an important component of the signal. The result is a strong signal in the form of a synthesized single sideband with all the useful modulation in the brief phase reversal period with a constant signal in the remainder of the bit period that can be used to establish a reference to create uniform time rise and amplitude.
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