Abstract: A statistical data detection method for use in a synchronous data transmission system employing either phase modulation, combined amplitude and phase modulation or quadrature amplitude modulation. The signal space diagram of the possible states of the transmitted signal and their influence zones is divided into N elementary squares. Since the squares are rather coarse to save storage space, many such squares belong to more than one influence zone. The influence zone of a state Z defines the region within which the received signal, P, will lie when state Z has been transmitted.A word in a ROM is assigned to each elementary square, and each word comprises two entries. The entries are identical when a square falls wholly within a single influence zone. Otherwise, the entries are different. Parts of the received signal are converted into an address for addressing the ROM.

Abstract: A digital phase filter including two decision filters connected in cascade or parallel for minimizing the noise components in a received phase modulated digital signal. The first decision filter cancels the residual noise component representing the phase intercept component and the phase shift component introduced by frequency shift, and the second decision filter minimizes the random noise component representing phase jitter and white noise.