Laboratory Experiments to Investigate Effects and Causes of Doppler Spreading in Heterodyne Correlators.
Abstract
It was found that there was a 6 db correlation loss at the lower sample rate (200 Hz) compared with the two higher sample rates (400 Hz and 800 Hz) when processing a zero doppler 100 Hz bandwidth PN signal. An investigation showed that at the 200 Hz sample rate, the correlator output was divided nearly equally between two comb-filter teeth which were located a distance of two teeth on either side of the zero doppler tooth. This frequency splitting was not observed at the higher sample rates. The cause of this problem was traced to slight frequency errors in the correlator's heterodyne oscillators. When the oscillators were replaced with precise frequency sources, the problem disappeared.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 13, 1966
- Accession Number
- ADA048865
Entities
People
- L. Strauss
- P. H. Hawkes
Organizations
- Navy Electronics Laboratory