Broadband amplifiers with tunable transmission characteristics

May 24, 2017 // By Jean-Pierre Joosting
The BBA130 broadband amplifiers from Rohde & Schwarz claim to be the first amplifiers in the 80 MHz to 6 GHz range that allow users to optimize the transmission characteristics to the requirements of a specific application.

The operating class for the transistors can be adjusted between Class A and Class AB during operation. The tolerance against mismatch at the output can also be changed to provide more power. Just one amplifier covers a variety of test scenarios during design and product validation.

Targeting the test cycle in eMobility, Internet of Things, 5G and satellite communications, the BBA130 broadband amplifier family addresses a wide range of tests during design and product validation. The broadband amplifiers were designed for use in development, production and quality assurance and offer output powers from 22 W to 4200 W in the 80 MHz to 6 GHz frequency range. Thanks to their compact, modular design, the amplifiers can be optimally scaled and configured. This modular design also provide a secure investment with the option to add future power and frequency range upgrades.

Two control parameter settings are used to optimize the output signal from the amplifier: a continuously variable bias point between Class A and Class AB and the choice between maximum output power and high mismatch tolerance. The user can change the setting of both controls during operation, e.g., if the signal waveform changes or if different requirements are placed on the output signal while the test is running. Now only one amplifier is needed to measure a DUT's specified data and determine its load limits.

Varying the bias point for the transistors changes the output signal characteristics. A bias point in Class A yields very good linearity and good harmonic performance and is ideal for generating spectrally clean CW signals. A bias point in Class AB provides faithful reproduction of pulsed signals and improves the efficiency of the amplifier.