Generating local carrier wave signal - using three loops with voltage-controlled crystal oscillator in first loop generating reference frequency compared in phase and frequency with signal generated

摘要

In a first loop (1) including a first oscillator (4), the output signal in a first phase detector (6) is compared w.r.t. phase and frequency with the output signal from a second oscillator (8) in a second loop (2). The output signal from the first phase detector (6) is fed back partly to the first oscillator (4) for control of its frequency and partly via a first input on a summation device (12) in the second loop (2) to the second oscillator (8) for control of its frequency. Output signals from the second oscillator (8) are also fed to a second phase detector (13), arranged in a third loop (3). In this second phase detector the second oscillator output signal is compared with regard to phase and frequency with a received carrier wave fed to the second phase detector.