EEVengers, Assemble: ThunderScope! 350 MHz Oscilloscope Streams 1 GSa/s Over Thunderbolt

After six years of research and development, EEVengers' premiere open source hardware project, ThunderScope, is now available for pre-order on Crowd Supply. Three years ago, the project's leader, Aleksa Bjelogrlic, previewed the four-channel 350 MHz oscilloscope that samples at 1 GSa/s. Its marquee feature is that it streams the acquisition data at the full sample rate to a PC over Thunderbolt (USB 4) and costs less than $1,000, making it an open, powerful, and affordable addition to your electronics test bench!

Hackster previously covered ThunderScope when it was "just" an FPGA project and then when the campaign first went live on Crowd Supply. That was three years ago. Today, it is now available for pre-order.

ThunderScope is an open source (OSWHA CA000017) PC-attached oscilloscope with up to 350 MHz bandwidth that samples at 1 GSa/s. It comes in two form factors: a PCI-Express x4 (Gen 2) card or a Thunderbolt-enabled standalone enclosure. The Thunderbolt version is essentially the PCI-Express card in a custom enclosure. The (primary) user interface is an open source PC client called ngscopeclient, which runs on Windows, macOS, and Linux.

Laptops with ThunderBolt (USB4) turn ThunderScope into a fully portable solution. Neither the standalone nor PCIe version requires an external power supply because EEVengers kept the power requirements under 15 watts!

The ADC is a 12-bit ADC that samples at 1 Gigasamples per second. The front end also includes a selectable 50 ohm and 1 Mohm termination. This choice makes ThunderScope compatible with traditional passive probes and 50-ohm terminated active probes — such as the open source 2 GHz probe from James Wilson.

Even though the ADC is 12-bit, ThunderScope currently only supports eight-bit acquisitions. The necessary hooks are in place, but Bjelogrlic says additional development is needed. Also, when operating in 12-bit mode, the sample rate drops to 500 MSa/s.

ThunderScope's native bandwidth is at least 500 MHz. However, EEVengers limits the measurement bandwidth to 350 MHz with an anti-aliasing filter that provides 3.5X oversampling. You can, however, turn off that filter. One trade-off to consider is that the analog channels share the 1 GSa/s ADC. When using more than one channel, ThunderScope's effective bandwidth reduces to 200 MHz (two channels) or 100 MHz (four channels).

Like some other PC-attached oscilloscopes, ThunderScope does not have an acquisition buffer. Instead, it streams the ADC samples at full speed to the PC at 1 Gigabyte per second — something no other oscilloscope does! ThunderScope opens up a new realm of analysis capabilities by combining that stream with GPU-accelerated software.

There are two open source client software options (today). One project, still under active development, led by whitequark is called thunderscope-rs. This option is a lightweight triggering and control client to get to probing signals quickly.

ThunderScope's primary user interface is Andrew Zonenberg's feature-rich ngscopeclient. This software is a front-end for the acquisition hardware (test equipment like oscilloscopes) and provides analysis capabilities. For example, it has a node editor that lets the user chain together filters, embedded-clock recovery, and analysis tools like eye diagrams. It also supports most serial protocols. In addition to ThunderScope, it can connect to other oscilloscopes!

Over the past three years, Bjelogrlic has assembled an incredible hardware, FPGA, and software engineering team. It is fantastic to see everything come together and even more astonishing that this measurement capability is entirely open source. The ThunderScope GitHub repository contains firmware, TS-specific software libraries for ngscopeclient, and hardware schematics. Another welcomed change since the first announcement is that Bjelogrlic is updating the (future) design files to KiCad!

ThunderScope is available for pre-order today. The PCIe card costs $800. For $950, you get a calibrated ThunderScope in an aluminum enclosure with a USB-C cable rated for 40 Gbps and a custom-fitted Pelican-brand transit case. Both price points include free worldwide shipping, but neither comes with probes.

Visit the ThunderScope Crowd Supply product page to place a pre-order or find links to related open source projects. The page also lists Bjelogrlic's talks over the past three years, which touched on many aspects of ThunderScope's development.