I'm working on a continuum interferometer project (actually resurrecting
one that has been dormant for several years). I'm currently
playing with approaches for spectral estimating with a two-antenna
interferometer system. I think, ideally, since you have two antennae,
you'd like to take advantage of that for producing spectral estimates
that have channel-electronics-induced-spurs reduced in magnitude,
and the spectral components that are common to the two antennas
enhanced. I've tried various approaches:
o Add the magnitudes of the FFTs for two antennae, low pass filter that
This produces a *composite* spectral estimate, including the
components due to independent spurs on the two channels.
o Complex multiply the two FFT outputs, then compute the magnitude,
low-pass filter that
This seems to produce some suppression of distinct components
that aren't common to the two sides
The absolute magnitudes of non-suppressed components are
obviously larger, due to the multiply.
The second approach seems very similar to what ALMA is doing for their
FX correlators.
Any words of wisdom/advice?
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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