Thermal Noise Effects of a Simple Correlator for High Dynamic Range Measurements
Author: Brett T. Walkenhorst
Publication: EuCAP 2017
Copyright Owner: NSI-MI Technologies
In order to achieve high accuracy in measuring sidelobes and/or nulls in antenna patterns, it is necessary to use a test system with very high dynamic range. This is particularly important when the antenna has extremely high gain such as those used for certain satellite communications or radio astronomy applications or when transmit power is limited relative to range loss as is often the case in millimeter wave applications. For several years, commercially available antenna measurement receivers have offered a dynamic range as high as 135dB for such applications. This dynamic range has been made possible, in part, by a simple correlator in the receiver’s DSP chain. In a previous paper, noise-free signal models were developed and analyzed to demonstrate the correlator’s ability to reduce carrier frequency offset (CFO) and local oscillator (LO) phase noise to offer the fidelity of test signal necessary to achieve extremely high dynamic ranges of up to 135dB. Building on those models, this paper models the effects of thermal noise and analyzes situations where the correlator works well and where it negatively impacts performance.