Toruń Centre for Astronomy
Nicolaus Copernicus University

Signal loss due to imperfect fringe rotation in VLBI correlators revisited

Borkowski Kazimierz M.
1986

In light of discrepancies seen in the literature (Fridman, 1983, and Gubanov, 1983), regarding signal-to-noise loss due to quantization of the fringe rotation function (FRF), related to very-long-baseline-interferometry (VLBI) signal processing, a more general expression is derived for the SNR loss, which validates a relation to the harmonic content of the FRF. Practical formulae are derived for calculating the SNR losses caused by quantization of the lobe rotation function in digital VLBI correlators. Examples are given for a few of the simpler rotation schemes.

Keywords
Correlators, Diffraction Patterns, Signal To Noise Ratios, Very Long Base Interferometry, Cosine Series, Counter Rotation