Spectral Deformation
Digital signal processing artifacts introduced during multirate downsampling alter the amplitude and phase fidelity of a digitizer output. In high-resolution sensor interfaces, decimation filter distortion arises when finite impulse response or cascaded integrator-comb architectures attenuate passband frequencies unevenly or leak stopband aliases into the baseband. The phenomenon sets the upper boundary of achievable spurious-free dynamic range in sigma-delta analog-to-digital converters before external calibration applies.
It stops applying once raw, un-decimated high-rate samples are processed directly without rate reduction.
Phase Nonlinearity
Non-linear group delay across the passband perturbs phase-sensitive measurements in vibration and acoustic sensing arrays. When linear-phase finite impulse response filters are truncated to save silicon area or reduce latency, the resulting ripple introduces decimation filter distortion that degrades time-domain step responses. Higher filter orders suppress alias intrusion but introduce group delay penalties that disrupt real-time control loops.
Quantization Artifact
Internal word-length truncation inside intermediate accumulator stages creates limit cycles. This finite precision noise combines with passband ripple to elevate the signal chain floor above nominal manufacturer specifications.
Bandwidth Limitation
Verification of passband flatness requires swept single-tone synthesized inputs referenced against a calibrated primary voltage standard. System integrators establish passband tolerance boundaries at the lower cutoff frequency, where gain droop first exceeds 0.01 decibels. Environmental temperature shifts alter internal clock timing slightly, altering filter transition bands relative to fixed analog anti-aliasing filters.
