Low power radio synthesizer with harmonic identification feature

摘要

A channelized radio has a phase-lock loop which locks to any one of a plurality of carrier frequencies. These frequencies are harmonics of a reference signal. A harmonic identification circuit is disclosed which produces harmonics of a reference signal which is slightly offset from the original reference signal. The offset harmonic which is closest to the locked frequency is compared with the locked frequency and a difference measurement is produced. This difference measurement identifies the locked frequency and enables the operator to lock to a new frequency if desired.