To compare the spectral efficiencies of PDSM and VPPM, the spectra of both pulse types can be represented as Fourier transforms.
4 compares the spectra of PDSM and VPPM pulse waveforms at light intensity indices of 0.
25, the PDSM pulse covers 90% of the pulse energy below 1334 Hz, whereas the VPPM pulse covers 90% of the pulse energy below 2619 Hz, which means that PDSM uses approximately one half of the required frequency bandwidth required to deliver the VPPM pulse at the same light intensity.
A low-pass filter (LPF) is used as a receive filter to suppress noise, and to show the effect of an LPF on a PDSM pulse, the LPF outputs of a pulse with light intensity index [beta] = 0.
9 shows graphs of both the simulated and analytical BERs of a PDSM signal with A = 1, T = 1 ms, [p.
To develop a correlation detector for PDSM and VPPM, we start with a case in which there is no idle pulse, i.
and, using the correlation detection relation, the BER of the PDSM signal becomes
To determine the BER of a PDSM signal using dual sampling, (12), with [p.
i] > 0; therefore, we used a Monte Carlo simulation to determine the BER of correlation detection for PDSM and VPPM signals that include the idle state, and we used (12) to determine the BER of PDSM using dual sampling.