Optically isolated measurement system with 1 GHz bandwidth

August 21, 2016 // By Jean-Pierre Joosting
The IsoVu™ measurement system form Tektronix, previewed earlier this year at the APEC 2016 show, is now shipping and available for worldwide delivery to customers. It combines wide common mode range, 120 dB common mode rejection and 1 GHz bandwidth, enabling previously hidden signals to be made visible.

The IsoVu™ platform uses an electro-optic sensor to convert input signals to optical modulation, electrically isolating the device-under-test from a Tektronix oscilloscope. The system incorporates four separate lasers, an optical sensor, five optical fibers, and sophisticated feedback and control techniques. The sensor head, which connects to the test point, has complete electrical isolation and is powered over one of the optical fibers. Ten patent applications have been filed for this ground breaking technology.

A critical advantage this technology offers for designers, such as those working on power devices involving GaN and SiC technologies, is superior common mode rejection that makes signals previously buried in common mode noise visible for the first time. IsoVu offers 1,000,000:1 (120 dB) common mode rejection (CMRR) up to 100 MHz and 10,000:1 (80 dB) CMRR at 1 GHz. By comparison, competitive systems at 100 MHz offer approximately 20 dB CMRR at 100 MHz, making IsoVu 100,000 times better.

"The feedback we received from designers at APEC was overwhelmingly positive, with many of them facing a critical need for the design insights IsoVu now makes possible," said Chris Witt, general manager, Time Domain Business Unit, Tektronix. "Currently there is no measurement system on the market with IsoVu's combination of high bandwidth, 2000 V common mode voltage range and breakthrough common mode rejection ratio."