IEEE 31- Microwave Correlator Based on a Nonuniformly Spaced Photonic Microwave Delay-Line Filter


We propose and demonstrate a novel technique to
perform matched filtering of a phase-coded microwave signal
using a photonic microwave delay-line filter. The photonic microwave
delay-line filter is designed to have a frequency response
that is conjugate to the spectrum of the phase-coded microwave
signal. To implement the delay-line filter, the tap coefficients
are usually complex, which is difficult to implement in the optical
domain. In this letter, a photonic microwave delay-line
filter with equivalent complex coefficients implemented using an
all-positive-coefficient photonic microwave delay-line filter based
on a nonuniformly spaced delay-line structure is proposed. Since
only positive coefficients are required, the implementation of
the filter is greatly simplified. An experiment is performed. The
decoding of a 6.75-GHz binary-phase-coded microwave signal is
experimentally demonstrated.