Resolved component indicator based on digitally generated quadrature references
T.G. Izatt, E. Ball · Electronics Letters · 1979
A resolved component indicator based on fixed-frequency quadrature square-wave reference signals has been developed, which has the property of rejecting unwanted noise and harmonics in the output of the system under test and which indicates the amplitude to better than 2% and phase angle to within 0.5° over the frequency range 10 Hz to 10 kHz.