1. A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: (a) converting digital data which are present as a sequence of symbols .alpha..sub.k, which symbols have a given time interval T and may assume M values, into a symbol vector c.sub.k or M.sup.L components; (b) converting said symbol vector c.sub.k into a time-dependent scalar envelope signal v(t) using a baseband filter having a characteristic r(t) of M.sup.L components, where ##EQU18## (c) phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response h.sub.c (t), an additive, white Gaussian noise w(t) being superimposed, so that at a receiver the envelop signal v(t) is transformed into a signal y(t) of the form EQU y(t)=h.sub.c *v(t)+w(t) , where "*" denotes a convolution product; (d) demodulating said carrier wave into said signal y(t); (e) filtering said signal y(t) by a channel specific filter of the form h.sub.c *(-t) for getting sufficient statistics in a subsequent sampling step; (f) filtering said filtered signal y(t) by an adjoined baseband filter of M.sup.L components of the form EQU r.sup.30 (-t), wherein ".sup.+ " denotes conjugate complex; (g) sampling the filtered signal produced by step (f) after the adjoined baseband filter at points of time kT, where k denotes an integer; and (h) determining, based on the sampled filtered signal produced by step (g), a sequence of estimated symbols .alpha..sub.k by an optimization algorithm.