Accession Number:

AD0441214

Title:

BANDWIDTH AND SPECTRA OF PHASE- AND FREQUENCYMODULATED WAVES,

Descriptive Note:

Corporate Author:

STANFORD UNIV CA STANFORD ELECTRONICS LABS

Personal Author(s):

• Abramson, Norman

Report Date:

1962-10-01

Pagination or Media Count:

21.0

Abstract:

The spectrum of a cosine angle-modulated by a Gaussian random process GRP of almost arbitrary spectrum is investigated. Such a GRP provides a convenient model for voice signals, TV signals, and other types of complex communication signals. A simple closed form expression for the bandwidth of the modulated signal in terms of the bandwidth of the modulating signal is found. A general expansion for the shape of the spectrum of the modulated cosine is derived.. In addition to reducing, in certain limiting situations, to known results, this expansion provides a practical means of obtaining the spectrum in intermediate cases. Examples are presented showing the spectrum of a cosine modulated by 1 a lowpass GRP with rectangular spectrum, and 2 a bandpass GRP of Gaussian spectrum. Author

Descriptors:

• *PHASE MODULATION
• BANDWIDTH
• FREQUENCY MODULATION
• TELEVISION SYSTEMS
• BAND SPECTRA
• STATISTICAL FUNCTIONS
• INTEGRAL TRANSFORMS
• INFORMATION THEORY

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE