Antialiasing in BBD Chips Using BLEP
Several methods exist in the literature to accurately simulate Bucket
Brigade Device (BBD) chips, which are widely used in analog
delay-based audio effects for their characteristic lo-fi sound, which
is affected by noise, nonlinearities and aliasing. The latter is a desired quality, being typical of those chips. However, when simulating BBDs in a discrete-time domain environment, additional aliasing components occur that need to be suppressed. In this work, we
propose a novel method that applies the Bandlimited Step (BLEP)
technique, effectively minimizing aliasing artifacts introduced by
the simulation. The paper provides some insights on the design
of a BBD simulation using interpolation at the input for clock rate
conversion and, most importantly, shows how BLEP can be effective in reducing unwanted aliasing artifacts. Interpolation is shown
to have minor importance in the reduction of spurious components.