Digitally-synchronized sweep signal source

Abstract

A swept synthesizer signal source provides a digital synchronization signal for accurate internal synchronization of events and for external synchronization of data taking and other operations to predetermined frequencies generated by an oscillator during a sweep. The digital synchronication signal includes a predetermined number of digital pulses, regardless of the sweep time. A ramp voltage which controls the oscillator is corrected during a calibration period to sweep between predetermined limits, thereby insuring that the ramp voltage is synchronized to the digital synchronication signal. The slope of the frequency versus time sweep is also corrected to further improve accuracy. A power level correction technique insures precision power leveling regardless of the sweep range. A table of correction/frequency pairs is entered into the instrument, and an interpolation algorithm is employed to determine corrections at frequencies corresponding to each synchronization pulse. The source can be used in a network analyzer system wherein the synchronization pulses are provided to a receiver to trigger data taking. Two or more sources can be interconnected to provide synchronized sweeps.