A Focal Plane Array Autocorrelation Spectrometer (FAAS) will be built in order to realize the full potential of a 15 element array receiver at the Five College Radio Astronomy Observatory (FCRAO). This 16,384 channel autocorrelator will utilize correlator chips developed by the Netherlands Foundation for Research in Astronomy. The fundamental clock rate of the correlator is 40MHz. The FAAS will provide 1024 spectral channels, with 20MHz bandwidth, for each of the elements of the array receiver. The FAAS spectrometer can time multiplex the input signal to achieve 200km/sec of bandwidth and approximately 1km/sec resolution for the CO J=1-0 transition. The FAAS is designed to operate also as a hebrid spectrometer for a single receiver. With approximately 15000 channels per receiver bandwidth.