Phasenregelschleife mit umschaltbarer Schleifenbandbreite

The frequency dividing circuit (70) is coupled from the voltage controlled oscillator (VCO) (60) output, while a phase detector circuit (20) is coupled from the frequency dividing circuit and the reference frequency source (10). The high loop bandwidth is determined by a loop filter circuit (30), linked from the output of the phase detector circuit. The low loop bandwidth is determined by a second loop filter circuit (40), whose output is connected to a control input of the VCO. For the high loop band width a voltage follower circuit (50) is incorporated between the two filter circuits. For the low bandwidth operation the voltage follower is disconnected, and the second filter circuit is coupled directly from the phase detector output. USE/ADVANTAGE - For TDMA radio systems, with switching of loop bandwidth in ratio of 1:100. Low-cost design with low current consumption.