This paper describes a digital null detector which is able to detect s
inusoidal signals in the presence of correlated noise. It is therefore
well suited for applications with multiple digital signal generators.
In particular, it is shown that the apparatus is suitable for separat
ing the glitch pulses of digital-to-analog converters from sinusoidal
signals. Numerical simulations on the influence of harmonic distortion
are also presented. Measurement uncertainties on a prototype were see
n to be up to six times smaller than on comparable lock-in algorithm-b
ased null detectors.