Restoration of Pulse Position Modulated Signal in a High Noise Environment
Abstract
The performance of a pulse position modulation (PPM) receiver, operating at a predetection signal-to-noise ratio below threshold, is severely degraded by the occurrence of anamolous pulses. The anamolies are caused by noise with sufficient amplitude to be detected as a signal pulse. The resultant multiple threshold crossings per sample frame severely degrade the demodulated version of the original message. In this report, a maximum a posteriori (MAP) amplitude sequence estimator is developed based on the Viterbi algorithm. The signal is modelled as a finite-state, discrete-time Markov process. The states correspond to the possible positions within a quantized version of the sample frame receiver structure and associated operating characteristics are presented in support of the concept of a quantized PPM frame. The pulse position/amplitude sequence is observed in white Gaussian noise, and probability of detection for each signal pulse is assumed equal to one. Monte Carlo simulation is used to determine the average performance of the estimator.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1982
- Accession Number
- ADA124902
Entities
People
- Kenneth N. Frankovich
Organizations
- Air Force Institute of Technology