The MWC can operate with as few as p = 2N channels and with a sampling rate fs = 1
/T > B on each channel,
so that it approaches the minimal rate of 2NB. Advanced configurations enable additional hardware savings by
collapsing the number of branches p by a factor of q at the expense of increasing the sampling rate of each channel
by the same factor [109]. The choice of periodic functions pi(t) is flexible: The highest Dirac frequency needs
to exceed fmax. In principle, any periodic function with high-speed transitions within the period T can satisfy
this requirement. One possible choice for pi(t) is a sign-alternating function, with M = 2L + 1 sign intervals
within the period T [109, 161]. Imperfect sign alternations are allowed as long as periodicity is maintained [9].
This property is crucial since precise sign alternations at high speeds are extremely difficult to maintain, whereas
simple hardware wirings ensure that pi(t) = pi(t + Tp) for every t 2 R. The waveforms pi(t) need low mutual
correlation in order to capture different mixtures of the spectrum. Popular binary patterns, e.g., the Gold or Kasami
sequences, are especially suitable for the MWC [161]. Another important practical design aspect is that the lowpass
filter h(t) does not have to be ideal. A nonflat frequency response can be compensated for in the digital domain,
using the algorithm developed in [162].
追问辛苦了，虽然不怎么符合，但还是把分送给你了。