Phase lock loop radio - has comparison integrator, with input current progressively increased with closing time, or phase error via resistance network

摘要

The tuning circuit has a phase lock loop and a frequency control loop. For the comparison in an integrator (37), the current increases progressively with the closure time period, or with the phase error of the respective branch of a phase discriminator. Pref. for adjusting the progressive current, suitable resistance networks are used. The resistance network (42) is realised by connection of partial resistors. Shift registers (40, 41) may be used as a phase discriminator, whose outputs are connected to a bus via suitable resistance networks, with the buses coupled to the integrator input. CMOS switches etc. may be used instead of conventional diodes. USE/ADVANTAGE - For tracking filters, frequency and phase (de)modulators, carrier regeneration etc. Has reduced lock-in time.