Continuum Observing at AO

Continuum observing at Arecibo can be made in two ways. Firstly, via detecting the signal by 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 X 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 connect the last part of the signal path manually via cables. The detailed procedure for this can be found in the 1999 Astronomy User's Manual as a webpage or a postscript file.

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