[cardiffspaceman]

In the 70's the company I worked for made a receiver for fixed frequencies within 10KHz-13KHz. The architecture roughly was discrete time analog, and an analog switch was available that took a digital selection and routed the indicated analog input to the analog output. That block was used to control the sampling for a filter by cycling through the selections. The rest of the design was over my head in those days, since I was the software guy and the software wasn't controlling that.