Demodulator arrangement.

摘要

The arrangement with a phase-locked loop PLL (11) having an output (17) coupled to an input (23) of a hold circuit (24) also comprises detection means (27) for detecting an instantaneous interference (Fig. 4b) in the signal present at the input (10) of the PLL (11) and for subsequently generating a control signal (Fig. 4e) which is applied to a control input (29) of the hold circuit (24). The hold circuit (24) is adapted to retain the signal applied to its input (23) during the time interval (T3) when the control signal is presented to its control input (29). The detection means (27) are adapted to determine a phase-lock error between the signal at the input (10) of the PLL (11) and the signal at the output (20) of the voltage-controlled oscillator VCO (19) associated with the PLL (11) and to generate the control signal if the phase-lock error exceeds a given value, for example, 45 DEG . A better detection of the instantaneous interferences can be realised with such an arrangement, rather than if the amplitude information (if present) of the signal at the input (10) of the PLL (11) had been used.