Accession Number:

ADA055170

Title:

Walsh Adaptive Filter

Descriptive Note:

Final technical rept. 2 Jun 1976-7 Dec 1977

Corporate Author:

AMERICAN ELECTRONIC LABS INC LANSDALE PA

Personal Author(s):

• Hurst, John F.

Report Date:

1978-04-01

Pagination or Media Count:

68.0

Abstract:

This report describes a technique and equipment for detecting pulsed signals in a high noise environment. The performance of this technique approaches matched filter techniques for signals where the pulse parameters are not known a-priori. A common problem in the area of signal processing is that of the detection of pulse signals having very low signal-to-noise ratios SNR. The problem is worsened when major signal parameters pulse width and time of arrival are not known. The purpose of this program was to develop an exploratory development model of a system to detect the presence of low SNR signals, on a single pulse-by-pulse basis. The technique chosen for this program was the use of the Walsh Transform as the basis for a two transform digital filter. This technique had previously been demonstrated both in software and in breadboard hardware form by AEL as a result on in-house IR and D programs. This program was to further develop the technique and to fabricate a unit suitable for test and evaluation purposes against a variety of potential applications. The system name, Walsh Adaptive Filter WAF, was derived from the use of a Walsh transform to adaptively filter signals of varying pulse widths and repetition rates. An exploratory development model was fabricated, tested and delivered to RADC.

Descriptors:

• *ADAPTIVE FILTERS
• *PULSES
• *RECEIVERS
• *SIGNAL TO NOISE RATIO
• DIGITAL FILTERS
• INFORMATION THEORY
• RECEPTION
• SIGNAL PROCESSING
• VIDEO FILTERS
• WALSH FUNCTIONS

Subject Categories:

• Cybernetics
• Non-Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE