OPTIMUM WAVEFORM STUDY FOR COHERENT PULSE DOPPLER
Abstract
The report contains the results of a theoretical investigation directed towards improving the sidelobe characteristics with respect to doppler of a swept frequency modulated signal. The methods of suppressing the time sidelobes analyzed were (a) Taylor frequency weighting in the receiver, (b) tone injection to predistort the phase of transmitted signal, (c) spectrum weighting by nonlinear FM of transmitted signal, (d) spectrum weighting by nonlinear FM in transmitter and frequency weighting in receiver, and (e) step-amplitude weighting in the transmitter. For each of the cases studied, where appreciable, normalized curves of the compressed signal time response are presented to illustrate the results. It has been found that nonlinear FM of the transmitted signal results in deterioration of the sidelobe performance with doppler due to phase mismatch in the receiver. A method that removes the effects of doppler on the received signal is frequency weighting of the transmitted signal. Step- amplitude modulation with a small number of steps is one method by which this weighting may be accomplished. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 28, 1965
- Accession Number
- AD0641391