Variable capacitor modulator used in directly modulated voltage controlled oscillators, includes switched trim capacitor connected between ground and nodes of varactor block already connected to tank circuit

摘要

The variable capacitor modulator includes a coupling capacitor for connecting nodes of a varactor block (16) to a tank circuit (14). A switched trim capacitor (26) connected between ground and respective nodes of the varactor block, trims the gain of the variable capacitor modulator. Independent claims are included for the following: (1) directly modulated voltage controlled oscillator; and (2) directly modulated VCO control method.