A STUDY OF THE SPECTRAL CHARACTERISTICS OF PULSE-POSITION MODULATED WAVEFORMS.
Abstract
The power spectral density of a pulse-position modulated (PPM) waveform is determined in part by certain statistics of the modulating process. In this paper a mathematical model is developed to determine the effects of three different modulating processes upon the power spectral density. The processes considered are the Gaussian, the exponential, and the uniform processes, with statistical independence assumed between the sample values that modulate the PPM waveform. The Gaussian process is also developed for the case in which statistical independence may not be assumed; that is, a correlation exists between the sample values of the modulating process. The model will also determine the power spectral density of pulse-amplitude modulated (PAM) waveforms, or for a combination of PAM and PPM. The mathematical model is reduced to a computer model and computed results are displayed. The design of a pulse-position modulator is shown, and experimental measurements of power spectra are compared with the theoretically determined spectra. The theoretical determination of power spectral density and the actual measurement of spectra of finite-time samples are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1964
- Accession Number
- AD0481412
Entities
People
- Arthur Augustus Bergman
Organizations
- Naval Postgraduate School