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Teardown: Infiniium MXR-Series Oscilloscopes

2021-08-03  |  8 min read 

The Signal Path did a teardown video of an 8-channel,  fully-loaded Keysight Infiniium MXR-Series oscilloscope — and put it through its paces, showing its incredible accuracy, superior noise performance, and declaring that the MXR-Series oscilloscope is an ideal solution as a tool for working in 5G or 6G.

The MXR-Series oscilloscope simultaneously supports 6 GHz at a rate of 16 Ga/sec on all 8 channels, with a dedicated trigger on the backside. Shahriar Shahramian pushes the MXR608A to the edge of its performance. The Signal Path examines a full-featured MXR-Series oscilloscope that integrates a logic analyzer, protocol analyzer, digital voltmeter (DVM), counter, bode plotter, waveform generator, and a real-time spectrum analyzer (RTSA) into the same compact chassis as the oscilloscope. 
Almost all the chips on the MXR-Series scopes are custom made because Keysight has developed the hardware architecture design across multiple technologies. These application-specific integrated chips (ASICs) were originally developed for Keysight’s high-end Infiniium UXR-series oscilloscopes and provide a huge performance benefit in the Infiniium MXR- and EXR-series scopes at a much lower cost. 
Ultra-high-speed memory in a hybrid memory cube (HMC) enables another unique feature of the MXR-Series (17:13). The MXR-series “…gives you 400 million points per channel independent of how you use them. Which of course is a huge advantage if you want to use all 8 channels at the same time.”
At about four minutes into the video, Shahriar starts analyzing the full acquisition board, including its analog front end (AFE). He compares and experiments with the RTSA, Direct Down Conversion (DDC) mode and digital sampling fast Fourier transforms (FFT) (20:48). The teardown discusses the need for a long capture duration if you want to have good resolution bandwidth and how the MXR-Series scopes allow you to look at up to 2 GHz of span on all the channels, independently. Shahriar states, “You can do all kinds of complex wireless system analysis on it that makes this a really good tool for 6G & 5G experiments.” (25:12) He goes on to discuss how the scope’s FFT, DDC-mode, and RTSA capabilities are different (see Table1). 

Table1: Comparison between frequency analysis tools on the Infiniium MXR-Series oscilloscope. (source: The Signal Path)

“In the real-time spectrum analyzer is where this thing goes crazy,” Shahriar says. “Here you have 320 MHz span maximum, and you have to share that between the channels — but it triggers, it captures so fast that you can capture a 15 µs interval signal with a one-hundred percent probability of intercept (POI) at full amplitude. These numbers are unheard of, for of course oscilloscopes — that's what spectrum analyzers with real-time analysis do and that's why the MXR is a multi-instrument in one.”
He also looks at the scope’s capabilities for analyzing a real-time eye diagram, jitter analysis, fault hunter, and equalization capabilities. Shahriar tests the MXR-series’ Fault Hunter feature by introducing a signal glitch that’s unrelated to his data stream, is infrequent or random, and can be completely different every time (39:36). You can also analyze a signal using the built-in Fault Hunter function. When you run the Fault Hunter, it starts capturing the data and runs statistical tests to find how the signal behaves on average. Then it runs tests and captures information before, during, and after the event if there are any outlying events. Accordingly, it generates a report that helps identify random faults that might occur in the next minute to 48-hours.
Most notable in the teardown video is that an MXR-Series scope can measure the tiniest signals with remarkable precision. Shahriar says, “Keysight claims that the MXR has an incredibly accurate internal time base.” He experiments on the MXR-Series’ time-based accuracy, frequency counter, and DVM (34:04) to see how good they perform and finds a “really, really impressive measurement” versus a rubidium atomic clock. Accuracy preserves signal integrity so that you are measuring what you want to measure, and less of what a scope can inject into your signals.
“Traditionally you couldn't do this in an oscilloscope, states Shahriar. “Let's say you have a SerDes, or you have a wireless transmitter, and you want to find out the difference between two crystals between a transmit and a receive. Or you want to compare your internal clock to let's say the GPS clock. Well, you can do that with the oscilloscope by directly feeding it into the unit. And you don't have to be capturing this data — these are done independent of the channel measurements. I think this is really an amazing feature they included for debugging of SerDes and wireless systems…instead of using a frequency counter.” 
MXR-Series oscilloscopes have a 15.6-inch full HD 1920 x 1080 resolution multi-touch capacitive display. Certain other functions are accessible directly from the screen and a matte display makes it easier to use in bright environments. The control buttons for all eight channels have LED backlights, so you can see which channels have been enabled and which ones are off. Each channel waveform is assigned a unique color. On the side, the scope has a VGA connector, two USB receptacles, and connectors for Ethernet, Audio, DisplayPort, and an easy-access, removable SDD slot. The BNC connectors on the right side of the scope are the arbitrary waveform generator’s (AWG) outputs. The scope’s BNC connectors are the same as prior oscilloscope generations, so you can reuse your existing probes and other equipment.
You can access more functions with Keysight’s PathWave Vector Signal Analysis software (89600 VSA). The many options in the PathWave VSA software enable you to explore virtually every facet of a signal and optimize your most advanced designs. As you assess the tradeoffs, PathWave VSA helps you see through the complexity. The combination of an Infiniium oscilloscope and 89600 VSA software is designed for analyzing complex wireless systems such as 5G and 6G. The 89600 VSA software is the heart of the ultra-broadband VSA and oscilloscope combination; providing flexible tools for analyzing and demodulating the most advanced digital modulations, including those not yet defined by an established standard.
The Infiniium MXR-Series scope combines more features than several individual benchtop devices. So far, we have discussed only the major utilities, but there is much more to discover. Check out the MXR-Series Datasheet for more details.