I am working on a project with a PLL synthesizer (ADF4110) for an FM receiver. There occurred following problem:
For the receiver, the phase noise at a distance of 20 kHz to the carrier is the most important parameter to comply with certain guidelines. This area is dominated (with correct dimensions of the loop filter) only by the VCO (channel spacing 20 kHz). Can the phase noise be minimized in this area without changing the VCO? The loop bandwidth is 240 Hz. Reducing the bandwidth has no effect.