The versatility of digital signal processing chips: Uses for these architecturally modified microprocessors go all the way from simple digital filtering to echo canceling

As more and more long-distance telephone calls are routed through satellites, echoes in conversations are I becoming particularly troublesome. Conventional echo suppressors do not work very well on satellite circuits, which have long propagation delays. What is needed is a sophisticated, adaptive approach to echo cancellation. But until recently such adaptive filters were too large and too expensive for widespread use. Each occupied a cabinet full of circuitry and cost tens of thousands of dollars.