Abstract: A speech synthesizer for developing a signal representing both voiced and fricative sounds from signals representing blocks of externally generated data, the synthesizer including a period counter for delineating a series of pitch periods each having a duration specified by the data, a source generator for developing an excitation signal having an amplitude specified by the data, the excitation signal being developed at the beginning of each of a series of constant duration sample intervals each with a random sign for fricative sounds, the excitation signal being developed at the beginning of each of the pitch periods for voiced sounds and a time multiplexed digital filter having characteristics specified by the data including circuit switching to control whether the filter functions as a second-order filter or a cascaded pair of first-order filters, the filter being driven by the excitation signal during the beginning of each of the sample intervals and by the output of the filter thereafter so as to develop