Accession Number:

ADA045662

Title:

Detectability of Linear FM Pulses Transmitted through a Random Medium,

Descriptive Note:

Corporate Author:

GENERAL ELECTRIC CO SYRACUSE N Y HEAVY MILITARY ELECTRONIC SYSTEMS

Personal Author(s):

Report Date:

1966-01-01

Pagination or Media Count:

24.0

Abstract:

The objective of the work to be described is to determine some of the implications of medium distortion on waveform and processor design for active echo-ranging sonar. In particular, the questions of bandwidth and duration of linear FM signals are considered, as well as various combinations of coherent and incoherent processing. Sonar echos are modeled as a multiplicity of discrete arrivals, the arrival time range, doppler shift and amplitude being chosen at random from specified probability densities. Noise is modeled as white with gaussian amplitude statistics, and reverberation as having gaussian amplitude statistics but the power spectrum of the transmitted signal. With these models, computer simulation is employed to examine the detectability of echos produced by the transmission of linear FM pulses of various bandwidths and durations. The processor consists of a correlator followed by various amounts and shapes of incoherent integration. Monte Carlo techniques are used to generate ROC curves, showing the probability of an echo being detected on a given ping vs the probability of a false detection in the absence of an echo, with input signal-to-noise ratio or signal-to-reverberation ratio as a parameter. The conclusion reached from these results is that best detection performance is obtained by use of a pulse with as much bandwidth as system constraints will permit.

Subject Categories:

  • Acoustic Detection and Detectors
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE