On the above equation, z[n] is the AWGN noise with single-sided noise spectral density [N.sub.0] which is added in one complete OFDM frame, and [x.sup.diff] [n] is the bipolar signal which is exactly equal to the 1st half of [x.sup.s1] [n].
Therefore, the average transmitted electrical power [P.sub.l] of the bipolar signal at the 1th stratum is given by
Figure 3(a) shows a bipolar signal
from an EHG register taken during the early stages of labor; the other three bipolar signals
are not shown due to space issues.
The generated bipolar signal
, [x.sub.n], is then converted to unipolar through clipping of all negative values at zero before modulating the LED.
Voltage models convert unipolar or bipolar signals
from [+ or -]1 V to [+ or -]150 V DC with multiple selectable ranges.