Frequency synthesiser for a broadband VHF-UHF receiver

摘要

The device includes a first mixer (5) which uses a first frequency synthesis loop (1) including a voltage controlled oscillator (14) controlled by a phase comparator (15). A variable divider-by-N (19) is coupled to the VCO by an intermediate frequency mixer stage (17) which gives a lower frequency. The divider output and the reference frequency input to a phase comparator to drive the VCO at a frequency proportional to the reference frequency. The second mixer (6) receives a signal from a second phase-locked frequency synthesis loop (2) comprising a second VCO (32) coupled to the input to a second phase comparator (34) by a mixer (35) which transposes the VCO signal to a lower frequency. The VCO is driven at a frequency proportional to the reference frequency.