GENERATION OF ACCURATE FREQUENCY-SWEEP WAVEFORMS BY DIRECT SYNTHESIS
Abstract
A signal whose frequency is a continuously varying function of time may be synthesized to any desired accuracy by digitally programming a direct frequency synthesizer. A synthesizer of this type can be modified to obtain phase-coherent frequency switching within a few hundred nanoseconds. The practicality of this mode of synthesizer operation has been demonstrated by the operation of a frequency-synthesized hf meteor radar. Two synthesizers were modified and electronically programmed to generate 100-kc, 1-sec, linear frequency sweeps. The radar achieves close to the theoretically expected range and doppler resolutions of 1.5 km and 1 cps, respectively. It is expected that this extension of the use of frequency synthesizers for generating other than constant- or steppedfrequency signals will find many other applications where signals of precisely time-varying frequency are needed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1964
- Accession Number
- AD0456205
Entities
People
- G. H. Barry
- R. B. Fenwick
Organizations
- Stanford University