Practical Modeling of Bucket Brigade Device Circuits
Practical Modeling of Bucket Brigade Device Circuits
Colin Raffel, CCRMA MA/MST student
This talk will discuss the sonic characteristics of the bucket-brigade device (BBD) and their associated circuitry. BBDs are integrated circuits which sample the incoming audio signal and produce a time-delayed version at their output. In order to reduce the aliasing corresponding to the sampling process, BBDs are typically preceded and followed by low-pass filters. Due to transfer inefficiencies and noise problems, BBD circuits also typically involve pre-compression and post-expansion (companding). The BBDs themselves also introduce certain nonlinearities and frequency-depended insertion gain.
Through circuit analysis and measurements, each component of the typical BBD system can be accurately modeled. This talk will discuss various techniques for modeling each component, with an emphasis on the importance of modeling each characteristic effect. In particular, the different modeling requirements of echo circuits and chorus, vibrato, and flanger circuits will be compared.