Programmable attenuator systems are needed for a variety of applications. Programmable, or step, attenuators can be controlled by either analog or digital control signals. They can also be controlled either manually or via a computer. In the application note, “An Introduction to Programmable Attenuator Systems,” JFW Industries describes various types of programmable attenuator systems and how they can be used to satisfy the requirements of different applications.
Programmable attenuator systems can be used to test the performance of such wireless applications as first responder, Wi-Fi, and cellular networks. Important specifications of a programmable attenuator include frequency range, attenuation range and step size, maximum RF input power, and insertion loss. As an example, the application note shows a specification sheet for a presently available programmable attenuator assembly.
A few different programmable attenuator system architectures are discussed. The first one presented is the parallel test system architecture, which the document identifies as the simplest configuration. A block diagram is shown to illustrate how each attenuator in the system has an independent input and output, as well as the fact that there is no RF connection between attenuators. This parallel architecture is typically used to simultaneously test multiple independent receivers and transmitters in a production environment.
Handover test systems are also described, as these systems are well suited for cellular and Wi-Fi testing. Handover test systems include attenuators and power dividers, providing connections for multiple network access points and devices. A block diagram of a handover test system is presented to illustrate its functionality.
The final type of system presented is the transceiver test system, which the document describes as the most complex type of configuration. These systems can accommodate the largest amount of device combinations and can perform most types of RF testing. A block diagram of a transceiver test system is also shown. The document also explains the differences between full fan-out, limited fan-out, and hub fan-out transceiver test systems.
JFW Industries, 5134 Commerce Square Dr., Indianapolis, IN 46237; (877) 887-4539