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Record Details

Record 27 of 481
Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model
Author and Affiliation:
Kory, Carol L.(Analex Corp., Cleveland, OH United States)
Andro, Monty(NASA Glenn Research Center, Cleveland, OH United States)
Abstract: For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept- amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.
Publication Date: Jan 01, 2002
Document ID:
20030010295
(Acquired Feb 07, 2003)
Subject Category: ELECTRONICS AND ELECTRICAL ENGINEERING
Report/Patent Number: AIAA Paper 2002-1896
Document Type: Preprint
Meeting Information: 20th AIAA International Communication Satellite Systems Conference and Exhibit; 12-15 May 2002; Montreal, Quebec; Canada
Meeting Sponsor: American Inst. of Aeronautics and Astronautics; United States
Financial Sponsor: NASA Glenn Research Center; Cleveland, OH, United States
Organization Source: NASA Glenn Research Center; Cleveland, OH, United States
Description: 11p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: INTERSYMBOLIC INTERFERENCE; MATHEMATICAL MODELS; TIME DEPENDENCE; TRAVELING WAVE TUBES; THREE DIMENSIONAL MODELS; SIGNAL PROCESSING; POWER AMPLIFIERS; QUADRATURE AMPLITUDE MODULATION; BACKWARD WAVES; HARMONICS; SIMULATION
Availability Source: Other Sources
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