An improved correlator for ALMA has been proposed by an European consortium including Astron (NL), Bordeaux University (FR), IRAM (FR) and Arcetri. ... The work in Arcetri has focused on the efficent design of a digital receiver, that exploits the peculiarities of the astronomical signal, i.e. the extremely coarse quantization and the stochastic nature of the input signal. ... A complex mixer followed by a two stage bandpass filter. ... Phase effects in a hybrid correlator . ...