Resumo

NAKAMURA-LABASTIDA, E.K; MOUSATOV, A  e  ALCANTARA-SILVA, R. System of nanosignal measurements at ultralow frequencies using synchronous detection technique. Ing. invest. y tecnol. [online]. 2007, vol.8, n.4, pp.227-240. ISSN 2594-0732.

In this work the prototype of a measuring system for nano-signals at ultralow frequencies (ULF) is presented. This system permits to reach high levels of Q-factor and signal to noise ratio by using the synchronous detection technique (SD). Based on the oretical study, the main properties of signals with several structures of periodic sequences (wave form, cycle number, duration) were obtained to optimize the application of synchronous detection as a filter ing technique. The SD simulation as a filter ing process allowed establishing the constitutive blocks to the prototype of electronic measuring system. The prototype was manufactured and submitted to experimental laboratory tests. The measuring accuracy with this system achieved 93-94% for 40nV signals and intrinsic noise of 3-3.2 nV. The experimental results have shown that the equipment and the synchronous detection technique are appropriate for measurements of nano-signals at ultra low frequencies.

Palavras-chave : Measurement system; synchronous detection; coherent detection; nano-signals; harmonic elimination.