A HIGH-SPEED DIGITAL CORRELATOR FOR RADIO ASTRONOMY

Design details for a high-speed digital cross correlator for the Owens Valley Millimeter Array are presented. The correlator uses ECL gate a rrays operating at 256 MHz clock rate to compute the real cross correl ation function for up to four independent frequency hands with bandwid ths in the range of 2-128 MHz. For each baseline in the array the corr elator provides 512 lags giving a spectral resolution of 2 MHz at the maximum bandwidth. Two-bit digitization is used, and this results in a sensitivity of 0.88 relative to a perfect analog correlator.