LARGE-ARRAY SIGNAL AND NOISE ANALYSIS. SHORT-PERIOD NOISE COHERENCE AMONG SUBARRAYS
Abstract
Much of the analysis of the mantle P-wave noise proposed for this contract depended on the ability to perform coherent processing by treating seismic noise as a compilation of plane waves using the large aperture available at LASA. The subarray outputs should be P-wave-limited, and the large array could be used to dissect the P-wave noise; therefore, it is extremely important to understand the coherence of the subarray outputs. This report presents the results of coherence studies among subarrays. Principal results of the study include the development of a program to compute multiple coherences and thus estimate multichannel coherence. A new processing technique to design filters that maximize the coherence between the output of two groups of sensors (group coherence) was developed and programmed. Presented are results of measured 2- channel and multiple coherence, indicating that the subarray outputs generally are moderately coherent below about 1 cps only within the B ring of the subarrays. Also presented are 2-channel and multiple coherences for several possible noise models. A study of these coherences suggest that the most reasonable models would give little coherence between A0 and the E and F rings. Comparison of model-study results with measured coherences suggests that a considerable portion (25 percent or more) of the subarray output power is not interpretable as seismic energy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 20, 1967
- Accession Number
- AD0823517
Entities
People
- Frank H. Binder
Organizations
- Texas Instruments