Title: Very Long Baseline Interferometry with Large Effective Bandwidth for Phase‐Delay Measurements
Abstract: The degree of delay‐measurement precision that is achievable by very long baseline interferometry depends on the effective bandwidth of the recorded signals. Methods of extending the effective recorded bandwidth for a fixed tape‐recorder bandwidth are examined in theory. Two major schemes (simultaneous recording of many widely separated frequency channels and recording sequentially different frequency channels) are examined in detail. Other techniques which involve rapid sampling and temporary ‘buffering’ of data bits are discussed. Methods of processing the data to achieve the maximum‐likelihood estimates of phase delay, fringe phase, and fringe rate are derived. Factors that determine the optimum choice of frequency channels are discussed by using a delay ‘resolution or ambiguity’ function. This function is analogous to the beam‐pattern function of a one‐dimensional antenna array. Theoretical signal‐to‐noise ratios for the delay and fringe phase measurements are derived by using a simple vector representation of the signal and noise.
Publication Year: 1970
Publication Date: 1970-10-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 185
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