- Bucket Brigade Device
A Bucket Brigade is an analogue delay line, developed in 1969 by F. Sangster and K. Teer of the Philips Research Labs. It consists of a series of
capacitance s C0 to Cn. The storedanalogue signal is moved along the line ofcapacitor s one step at each clock pulse. In general, bucket brigades have been replaced by devices which useDigital Signal Processing . However, many swear that digital devices do not provide the same warmth and tone that bucket brigades do, and they still see use in specialty applications, such asguitar effects .The name derives from a line of people passing
bucket s of water along the line.A well-known integrated circuit device around 1980, the RETICON SAD-1024 implemented two 512 stage analog delay lines in a 16-pin DIP. It allowed clock frequencies ranging from 1.5 kHz to more than 1.5 MHz. The SAD-512 was a single delay line version. The TDA1022 similarly offered a 512 stage delay line but with a clock rate range of 5-500 kHz.
Despite being analog in their representation of individual signal voltage samples, these devices are discrete in the time domain and thus are limited by the
Nyquist-Shannon sampling theorem ; both the input and output signals are generally low-pass filtered. The input must be low-pass filtered to avoidaliasing effects, while the output is low-pass filtered for reconstruction. (A low-pass is used as an approximation to theWhittaker–Shannon interpolation formula .)The concept of the Bucket Brigade Device lead to the
Charge-Coupled Device (CCD) developed byBell Labs .References
* Theuwissen, A. (1995). "Solid-State Imaging with Charge-Coupled Devices".
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