Linear noise reduction for a test and measurement system

A computer readable storage medium having instructions stored thereon that, when executed by a processor of a test and measurement system, cause the test and measurement system to:

• convert a digital signal into a complex frequency domain by applying a time-frequency transform to the digital signal, the digital signal including channel noise introduced by an analog to digital (A/D) converter that produced the digital signal;
• determine a signal circularity coefficient for the digital signal and a noise circularity coefficient for the channel noise;
• generate frequency domain coefficients for an adaptive linear filter through comparison of the signal circularity coefficient and the noise circularity coefficient through application of a randomness suppression factor for reduction of statistical errors caused by the comparison of the signal circularity coefficient and the noise circularity coefficient;
• and
• apply the adaptive linear filter to the digital signal to reduce the channel noise from the digital signal.

A method comprising:

• converting, by an analog to digital (A/D) converter, an analog input signal into a digital signal in a time domain;
• applying a time-frequency transform to convert the digital signal into a complex frequency domain signal;
• and
• displaying a spectrum from frames of the complex frequency domain signal, the spectrum displayed on a real axis and an imaginary axis, the spectrum further displaying a distribution of complex frequency domain signal power and complex frequency domain noise power as a function of digital signal phase and magnitude.