| 摘要 |
<p>A method as described for setting the frequency of an RF source containing an oscillator having coarse and fine frequency controlling elements for generating RF signals for testing the RF response of devices by sweeping the RF signal source through a band of frequencies and detecting and analysing the signal transmitted by the device under test. A coarse comb signal based on harmonics of a first signal NMHz, and a fine comb signal based on harmonics of a second signal nMHz (N being much greater than n), are generated and the coarse and fine frequency controlling elements are calibrated. The oscillators are then swept through the frequency to which a marker relates and just beyond to detect the presence of the leading and trailing edges of the marker and the fine tuning control signal values corresponding to the edges are noted, a value for the frequency controlling signal corresponding to the mid-position of the marker is computed from the arithmetic mean of the leading and trailing edge values, and thus computed value used to calibrate the oscillator subsequently. Apparatus for performing the method is also described.</p> |
