F Directory) ----------------------------------------------- SRF files contain power spectra derived from noise measure- ments when the radio system was stable and there were no spacecraft signals in the passband. SRF's were derived sepa- rately for each receiver channel; but the fact that the spectral characteristics of each receiver depended almost entirely on digital signal processing meant that there was little practical difference among channels when sampling rates (output bandwidths) were the same and the SRF's were inter