Tektronix unveils 1GHz optically isolated measurement system

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Tektronix has unveiled its IsoVu technology at APEC 2016, the technology is claimed to offer complete galvanic isolation between a device under test (DUT) and an oscilloscope through the use of electro-optical sensors. Tektronix says it will be the industry’s first measurement solution capable of accurately resolving high bandwidth differential signals in the presence of large common mode voltage. The technology will also offer immunity to external interference and radiated emissions, minimising the impact of EMI on measurements.

To date, design engineers working on power device designs involving GaN and SiC technologies and other high-speed applications have had no way to accurately visualise differential signals when common mode interference is present. As a result, these signals are essentially hidden, making it difficult for engineers to see what is actually occurring inside circuits, slowing debug and characterisation efforts. Engineers also face challenges making measurements in noisy environments or those that have high EMI.

The IsoVu technology is claimed to have the potential to resolve these challenges. It utilises an electro-optic sensor to convert the input signal to optical modulation, which electrically isolates the DUT from the oscilloscope. IsoVu will incorporate four separate lasers, an optical sensor, five optical fibres, 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 fibres.

Earl Thompson, senior vice president, Time Domain Business Unit, Tektronix, said: “An electrical connection between the oscilloscope and the DUT impacts measurement results. By moving to an optical connection, this technology has the potential to eliminate that as a problem and as a result could advance the state-of-the-art in power measurement and EMI test systems.”

IsoVu technology is claimed to offer greater than 120dB common mode rejection from DC to 100MHz which is said to be 33,000 times better than previously available measurement systems.At 1GHz, Tektronix says, it will provide 80dB common mode rejection at 1GHz, which is more than a thousand times better than previously available measurement systems. As a result, users will be able to measure anywhere in their circuit without common mode interference.

Using this technology, engineers will be able to accurately measure differential signals between 5mV and 50V in the presence of large common mode voltages less than 2kV from DC to 1GHz. This is also claimed to be the first signal acquisition product where the common mode voltage capability does not de-rate over bandwidth.

Additionally, Tektronix plans to offer a 10m fibre optic cable option to allow users to move their test system away from the interference and radiated emissions of the DUT. As such, it will be suited for remote testing and EMI validation applications.