摘要 |
A frequency arrangement with at least two successive heterodyne stages, one of which converts an input signal with an adjustable first frequency of a superposition oscillator that can be set in fine frequency increments into a first intermediate frequency, a second heterodyne stage that converts an input signal with a fixed second heterodyne frequency of a second superposition oscillator into a second intermediate frequency, the difference frequency between the first and second heterodyne frequencies is converted with an adjustable frequency divider into a lower frequency, which is then compared in a phase detector to the output frequency of a reference oscillator which is implemented as a synthesizer that can be set in fine frequency increments, the first superposition oscillator being synchronized with the output frequency of the reference oscillator via a phase control loop with the output signal of this phase detector, and the adjustable frequency divider preferably being a fractional N-divider with simple integration.
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