OSCILLATING CIRCUIT WITH TUNABLE FILTER FOR MINIMIZING PHASE NOISE

摘要

The present invention relates to an oscillating circuit arrangement (10) comprising a resonating arrangement with a first resonance frequency (coo) comprising a voltage controlled oscillator arrangement (10A) . It further comprises a tunable filter arrangement (25) connected to the source node of said voltage controlled oscillator (VCO) arrangement (10A) . Said filter arrangement (25) particularly comprises an equivalent current source resonating at a second resonance frequency c?f, the second resonance frequency being a multiple n,n= 1 or 2 of said first resonance frequency (a>o) , n being equal to the minimum number of switch transistors (li,--2) required for oscillation of said VCO arrangement. The filter arrangement particularly comprises an inductor (2) connected in parallel with a capacitor (3) , said capacitor (3) being adapted to be tunable such that the phase noise of the resonating arrangement (10A) can be minimized through tuning of the filter arrangement (25) .