Fractional Divider Concepts with Phase-Lock-Control for the Generation of Precise Linear Frequency Ramps

A highly linear analog frequency ramp generator based on a fractional divider concept is presented. The frequency ramp linearity achievable in this fractional phase-locked-loop configuration is excellent. This is revealed by numerical simulations as well as measurements performed with a prototype synthesizer implemented in a FMCW-radar system suitable for distance and velocity measurements.