Continuum Observing

Continuum observing at Arecibo can be made in two ways. Firstly, via square-law detectors, passing the output of these through integrators, and then recording the signal as a time series via the Radar Interface (RI). The RI consists of $4 \times
12$-bit Analog-Digital converters, a fifo buffer memory, packer, multiplexer, and control system. This can take dual-polarization data at a 10-MHz rate with quantization at 2 bits, or at slower rates with higher level quantization. To use this option, the user needs to set up the last part of the signal path manually via cables. The detailed procedure for this can be found in Astronomy User's Manual and is available via the link at http://www.naic.edu/~astro/continuum.shtml.

Secondly, the data can be recorded via a spectral-line spectrometer, and the measurements treated as spectral-line observations in which the spectral channels are subsequently collapsed across frequency during data analysis to give a broad-band continuum signal. This has the great advantage that radio interference can be edited out before the broad-band signal is derived.



Robert Minchin 2017-10-30