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PPM Receiver Implemented in SoftwareA computer program has been written as a tool for developing optical pulse-position- modulation (PPM) receivers in which photodetector outputs are fed to analog-to-digital converters (ADCs) and all subsequent signal processing is performed digitally. The program can be used, for example, to simulate an all-digital version of the PPM receiver described in Parallel Processing of Broad-Band PPM Signals (NPO-40711), which appears elsewhere in this issue of NASA Tech Briefs. The program can also be translated into a design for digital PPM receiver hardware. The most notable innovation embodied in the software and the underlying PPM-reception concept is a digital processing subsystem that performs synchronization of PPM time slots, even though the digital processing is, itself, asynchronous in the sense that no attempt is made to synchronize it with the incoming optical signal a priori and there is no feedback to analog signal processing subsystems or ADCs. Functions performed by the software receiver include time-slot synchronization, symbol synchronization, coding preprocessing, and diagnostic functions. The program is written in the MATLAB and Simulink software system. The software receiver is highly parameterized and, hence, programmable: for example, slot- and symbol-synchronization filters have programmable bandwidths.
Document ID
Document Type
Other - NASA Tech Brief
Gray, Andrew (California Inst. of Tech. Pasadena, CA, United States)
Kang, Edward (California Inst. of Tech. Pasadena, CA, United States)
Lay, Norman (California Inst. of Tech. Pasadena, CA, United States)
Vilnrotter, Victor (California Inst. of Tech. Pasadena, CA, United States)
Srinivasan, Meera (California Inst. of Tech. Pasadena, CA, United States)
Lee, Clement (California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
March 1, 2010
Publication Information
Publication: NASA Tech Briefs, March 2010
Subject Category
Man/System Technology and Life Support
Report/Patent Number
Distribution Limits
Public Use Permitted.

Available Downloads

NameType 20100009684.pdf STI

Related Records

IDRelationTitle20100009649Analytic PrimaryNASA Tech Briefs, March 2010