Fecha de publicación: 31/12/1985 Fuente: Wipo "digitalization" A digital loop filter is used in a phase-tracking circuit which is adaptable to a phase-comparison radio navigation system such as the DECCA (registered trademark) system. The digital loop filter includes a feedback circuit which receives a digital input signal from the digital loop filter and outputs a digital output signal and which feeds back and adds the digital output signal to the digital input signal after a predetermined delay. It also includes a feed-forward circuit which multiplies the digital input signal by a predetermined constant (B) and adds the resultant signal to the digital output signal of the feedback circuit to generate a digital output signal. A multiplier for multiplying the digital output signal of the feed-forward circuit by a second predetermined constant (C) to generate a digital output signal of the digital loop filter is also provided.