A central processing unit is a term that predates using the lithographic process for microprocessors. I have documentation trying to describe the signal process

A central processing unit is a term that predates using the lithographic process for microprocessors. I have documentation trying to describe the signal processing of early inertial guidance system. The documents describe all the input and output be routed to what they call a central processing unit. This unit contained many boards but centralized the signal routing to single area and could be processed in a sequence.