An Introduction to Programmable Attenuator Systems

An attenuator is an electrical component that reduces the amplitude of a signal passing through it without significantly degrading the integrity of that signal. In a programmable or step attenuator, the attenuation is controlled externally by an external analog or digital signal, either manually or via a computer. Depending on the model, the maximum attenuation ranges from 0 dB to 127 dB, in steps as small as 0.1 dB.The attenuator is controlled by a combination of digital inputs, an analog voltage or via USB, RS-232, Ethernet or GPIB.

This article will review the key components of a programmable attenuator system and discuss the best choices for some common applications.