Bucket-brigade device

A bucket brigade or bucket-brigade device (BBD) is a discrete-time analogue delay line,[1] developed in 1969 by F. Sangster and K. Teer of the Philips Research Labs in the Netherlands.

A well-known integrated circuit device around 1976, the Reticon SAD-1024[2] implemented two 512-stage analog delay lines in a 16-pin DIP.

The Philips Semiconductors TDA1022[3] similarly offered a 512-stage delay line but with a clock rate range of 5–500 kHz.

In 2009, the guitar effects pedal manufacturer Visual Sound recommissioned production of the Panasonic-designed MN3102[7] and MN3207[8] BBD chip.

The idea of using capacitors to retain a voltage state has older origins and separately led to dynamic random-access memory, where the charges are not propagated, but refreshed, in place.