Bit streams: an alternative approach to digital controller implementation

In a digital controller, a multi-bit binary word is produced at regular intervals, which an arithmetic unit uses to generate a new control word for the next sampling interval. This paper proposes a similar and yet a different technique to implement cascade controllers. Instead of a multi-bit word a single bit stream represents the analogue signal and elementary digital gates implement the required control algorithm. Bit-stream controllers for two single-input -single-output, SISO, systems have been successfully implemented and presented. The design methodology is similar to continuous time controllers and also offers the versatility of digital systems. The inherently parallel nature of this technique also makes it possible to implement controllers for larger and more complex multiple-input-multiple-output, MIMO, systems.