Patent ID: 6052571
Filing Date: 2000-04-18
Classification: H01F,H03B,H03J,H03L,H04L

Abstract:
A high frequency apparatus for use with a signal, said apparatus comprising:a mixer having:i) a first input coupled to the signal and,ii) a second input coupled to an output of a local oscillator, andiii) an output terminal coupled to an output signal of said mixer; said local oscillator includes:i) a voltage controlled oscillator, havinga) an oscillating section, andb) a tuning section including a frequency adjustment section for adjusting a frequency of the voltage controlled oscillator, andc) maintaining means for maintaining the frequency of the voltage controlled oscillator after adjustment of the frequency,ii) a frequency divider,iii) a phase comparator, andiv) a loop filter,wherein said frequency divider, said phase comparator and said loop filter are part of a control loop;said control loop having a loop band width such that a noise effect of said local oscillator are not dominated by said voltage controlled oscillator.and a signal level of the reference frequency signal supplied to said phase comparator is lower than a signal level of a further frequency signal supplied from said frequency divider to said phase comparator within a respective frequency region including a predetermined region above and below the center frequency.