Frequency synthesising appts. - compares actual frequency with reference to set frequency of divider stages

摘要

The synthesiser has the frequency inputs of the first frequency divider stage (6,7) and second frequency divider stage (10) connected to the output of a digital pre-divider (4). The divider stages are actuated alternately depending on an overflow pulse from the other divider stage. The actual-frequency input of the comparator (13) is connected to the output of the second frequency divider stage. The stages' outputs are connected to the set and reset inputs of a bistable flip-flop (12) whose output switches the stages alternately on and off.