Record Details
Real-time bandwidth compression using Hilbert transforms
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Real-time bandwidth compression using Hilbert transforms |
| Names |
Bradley, Richard William
(creator) Weber, Leonard J. (advisor) |
| Date Issued | 1967-08-31 (iso8601) |
| Note | Graduation date: 1968 |
| Abstract | This paper presents a theoretical study of real-time bandwidth compression systems using the Hilbert transform and associated analytic signal concept. An analytic signal is defined as u(t) = s(t) + [superscript ¯]js(t) , where [superscript ¯]s(t) is the Hilbert transform of the signal s(t). A complete discussion of the properties of analytic signals is included. Speech bandwidth compression is emphasized, but the proposed compression schemes can be applied to any narrow-band (band-limited signal. The extent of compression depends largely upon the characteristics of the input signal. Two presently used real-time speech bandwidth compression systems, the Vobanc and channel Vocoder, are described in order to provide a comparison between the proposed systems and existing systems designed without recourse to analytic signal ideas. A recently introduced two-to-one bandwidth compression method based upon the analytic signal is described in detail. Methods for achieving bandwidth compressions by factors greater than two are considered. A new real-time bandwidth compression system referred to as the "repeated half-angle" system is suggested to obtain an eight-to-one speech bandwidth reduction. This system is relatively easy to implement as compared to present systems. The performance of this system is highly dependent upon the accuracy of the many multipliers, squarers, and root extractors required. |
| Genre | Thesis/Dissertation |
| Topic | Radio -- Transmitters and transmission |
| Identifier | http://hdl.handle.net/1957/47096 |
