MDO4104-6 Review

Tektronix loaned us a massive MDO4104-6 mixed domain oscilloscope for a few weeks. Not only does it show voltage over time, like you see on a standard scope or logic analyzer, it simultaneously measures the frequency domain. This is not just another scope with FFT, it has a fully functional spectrum analyzer built in. This is the same unit Dave at EEVblog reviewed earlier.

The MDO comes in four flavors. The high end model has an analog bandwidth of 1Ghz, and is capable of 6Ghz RF. The lower model can have any combination 500Mhz or 1GHz analog and 3GHZ or 6GHz RF.

Our first impression is that this is a large, heavy unit.  It has a fairly large 10.4 inch XGA(1024×768) display, useful when using all three scope features. It took over a minute to get to a useful screen after power up, and the standard color scheme makes it feel somewhat dated.

The user interface is a little sluggish. One interesting feature is that the entire scope can be controlled through a web interface. Overall the web interface is very sluggish, even with a direct gigabit connection. It may still come in handy if you must take a look when you are not at your workstation. The included software was not able to connect to the scope from a Windows 7 X64 PC, and we were not able to try it. The demo expansion modules also expired shortly after turning it on, and so we were unable to test them either.

Review and screenshots continue below.

The standard features found on any scopes in this class work as expected. The combination logic analyzer and oscilloscope saved much time debugging a complex series of interrupts.

Testing the RF section was a little more tedious. Using Ham radio gear, specifically an Alinco dj-S41, we noted that the MDO is only capable of sinking 1 watt into the RF input. Connecting any other radio avalable to us would have blown up the RF front end – since this has to make its way back to Tektronix, we really did not want to do that.

This screenshot shows a measurement of about 21dBm(130mW) from a FM carrier at 443MHz. Note the harmonics at 2MHz spacing. We were able to get a good update rate with 10MHZ capture and 1KHz windows.

Above is a spectrogram of our local 2.4GHz wireless networking. We had to set the reference level and the scale to see the histogram well while using the supplied telescoping antenna. This capture has a total bandwith of 200MHz and windows of 200KHz. you can see how wideband the WiFi signals are.

Overall we have enjoyed using this scope, even with the problems we previously covered. As this scope matures we expect these features to receive some attention, and improve. We do not recommend this for the hobbyist on account that the base model is just shy of 20K, however if your a professional that will use the RF features of this scope on a more than occasional basis, use your expense account to grab one. It’s an amazing piece of equipment, and we were reluctant to put it back in the box and return it to Tektronix.

The scope was provided by Tektronix for review and a road test. Firmware version 2.10 was installed at time of testing.

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  1. We had one of these demoed to us in our lab and it’s been left with us until after Christmas. It is very impressive piece of kit and proved immediately useful with the frequency/time plots which we were developing on FPGAs. The interface did feel every so slightly slugish, but really not enough to worry about, given the features it presents. After day one with this bit of kit, I want one!

  2. given all the little things i ran into, and the imminent updates for the firmware. i would jump on the chance to get my hands on another one.

    just waiting for the price to drop(or a free-bee)

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