Efficient digital sweep oscillator with extremely low sweep rates

Abstract

The performance of the Pedersen digital sweep oscillator is improved using a new technique which is intended to improve the sweep rates so that they can reach extremely low ranges without the need of increasing look-up table width. The proposed technique is shown to be very efficient in increasing the effective table length, and hence, the number of generated samples during the sweep time. The sweep rate is improved by storing and reading the sine and cosine components of two sweep functions that are not harmonically related, and then evaluating the sweep signal of the phase difference. Better performance can be achieved by using the trigonometric identity method as demonstrated. There are no limitations on the time-bandwidth product of the proposed structure. Performance calculations and simulation results are given to support the analytically claimed results and demonstrate the performance.