Extracting masked signal parameters with a synthetic instrument

Synthetic instruments apply the flexibility and computational capabilities of a digital signal-processing platform to synthesize a wide variety of synthetic instruments. We are often presented with measuring waveform characteristics containing known attributes and parameters. These parameters may include signal bandwidth, AM or FM modulation indices, spectral shape parameters and inserted pilot levels. The task of the synthetic instrument for this class of signals is to verify that the waveform parameters match the selected parameter settings. A related task is that the same waveform may contain undesired artifacts of the signal generation process. These artifacts might include spectral regrowth terms, spectral harmonics, and digital-to-analog converter noise. The task of the test equipment is to isolate and measure the parameters of these artifacts to verify they do not exceed specified acceptance criterion. Often, the undesired signal components and the desired components occupy overlapping spectral spans or the same spectral span. In this overlay scenario, the desired signal may mask the undesired components preventing the successful measurement and classification of these artifacts. This paper presents a class of signal extraction algorithms that separate desired signal components from undesired components. These algorithms use deterministic signal canceling and signal subtraction techniques to separate the desired and artifact components.