Spectra Display (SPD)

The Spectra Display tool SPD, runs on CACCC and is usually displayed on PERICLES. It is a useful correlator monitoring tool. SPD is started by typing spd in a CACCC window.

SPD displays data from the correlator, either in the lag domain - the correlation function as measured directly by the correlator, or in the frequency domain - the spectrum which results from the Fourier transform of the correlation function. The user can select which of the products contained within the correlator configuration to display and in what form to display them.

Note: The correlation function is always present for both positive and negative lags. If only positive lags are measured, as is normally the case in an autocorrelation function, the positive lag measurements are mirrored into the negative lags.

SPD can also display the bin profile for correlator configurations which provide time or pulsar binning.

There are two modes in which the user can operate to select which products to display.

• mode v - selection by variable or product number
• mode b - selection by baseline or polarisation