Topband: Group delay distortion in receiver filters

[John Kaufmann]

Joe Tik Mok wrote:

> Recently I'm studying the
> effect of group delay ripple/phase distortion on an optical pulse. I
wonder
> if there's such an analogy in the electrical signal processing? It seems
to
> me that this is actually rather thoroughly understood in signal processing
> but not in the optics.


The effects of phase distortion are completely analogous in both electrical
and optical signals.  I have worked professionally in both areas (I
currently work in the area of ultra-high speed fiberoptic transmission
systems).  In optical fiber, one of the distortion mechanisms, as you
undoubtedly know, is dispersion (chromatic, polarization, and modal).  Fiber
transmission systems that operate at the higher data rates use chromatic
dispersion compensation to achieve long transmission distances.  In
electrical systems, dispersion also occurs in transmission lines,
waveguides, and dispersive components, such as electrical filters.  The
physical details of how the phase distortions arise, and how they are
compensated, may be different but the same basic equations govern the
propagation of both electrical and optical signals and fields.

73, John W1FV