Fourier Transform (Spectrum) of QPSK and BPSK?

[[email protected]]

Hi All,

Does anyone have a mathematical derivation
of the expected spectrum of a QPSK signal, given a
known symbol rate (which is 1/2 the data rate for QPSK)?

The signal i am measuring doesn't have any
sideband carrier suppression at all, which is supposed
to be a figure of merit for phase and amplitude imbalance
of your IQ mixer (how orthogonal or in-quadrature the I and Q
channels are).

Thanks for any REAL help (which is Info from someone
who isn't pretending to know more than they actually do!).


Slick

 

[[email protected]]

Hi All,

Does anyone have a mathematical derivation
of the expected spectrum of a QPSK signal, given a
known symbol rate (which is 1/2 the data rate for QPSK)?

The signal i am measuring doesn't have any
sideband carrier suppression at all, which is supposed
to be a figure of merit for phase and amplitude imbalance
of your IQ mixer (how orthogonal or in-quadrature the I and Q
channels are).

Thanks for any REAL help (which is Info from someone
who isn't pretending to know more than they actually do!).

The bottom line is I'm trying to measure phase
and amplitude imbalance with just a spectrum analyzer,
without having to buy an expensive VSA which can display
the constellation, and give me EVM, etc.


SLick