50 GHz scope builds on Tek's ATI sampling technology

September 29, 2015 // By Graham Prophet
Tektronix has expanded its DPO70000SX ATI high performance oscilloscope family, with a 50 GHz model that it positions as suitable for datacom PAM4 (multi-level signalling) testing

The range expansion includes 50 GHz and 23 GHz models, both using Tek's asynchronous time interleaving (ATI) architecture, for technologies such as 28 GBaud PAM4 and Kband frequency testing. The 23 GHz instrument joins the existing 33GHz models which feature compact dimensions and built-in scalability using the UltraSync synchronisation technology.

The 50 GHz model is appropriate for engineers and researchers who do not need the full 70 GHz bandwidth of the flagship DPO70000SX oscilloscope, but want to take advantage of the low-noise performance of the patented asynchronous time interleaving (ATI) architecture.

Tek claims the lowest-noise and highest fidelity of any ultra-high bandwidth real-time oscilloscope available. As speeds go up and amplitudes go down, system noise has become a major challenge because it obscures important details in signal behaviour. Tektronix' 50 GHz and 70 GHz ATI oscilloscopes allow engineers to more accurately capture and measure higher frequency signals with up to 30% less system noise than the legacy frequency interleaving approaches used by other oscilloscope manufacturers.

Current real time scope solutions for digitizing ultra-high bandwidth signals distribute signal energy to two digitising paths then use DSP to reconstruct the input signal. In contrast, Tektronix' ATI architecture uses a symmetrical technique that delivers all signal energy to both digitising paths resulting in an inherent noise advantage when signals are reconstructed. The 50 GHz instrument's ATI channel offers 200 Gsample/sec sample rate for 5 psec/sample resolution. It also has two standard (non-ATI) 33 GHz channels with 100 Gsample/sec sample rate for 10 psec/sample resolution.

To further enhance signal fidelity, DPO70000SX oscilloscopes use a compact 5.25-in. form factor so the instrument can be positioned very close to the device under test (DUT) for shorter cable lengths and cleaner signals. The low height means each unit fits in a single 3U rackmount space, or two oscilloscopes can be stacked in the same space as a single standard bench oscilloscope.

Precise multi-instrument timing synchronization is required