Hi:
Recently at work I reviewed Tek MSO4000, Tek DPO7000, Agilent 9000, and LeCroy MXi-A series oscilloscopes.
I have purchased recently an Agilent MSO7054B, Tek MSO4054, and LeCroy
104MXi-A.The only one I regret purchasing is the Tek. I would have preferred to have gotten their new MSO5000 model, but anyway...
The MSO4000 is my least favorite instrument, and will likely be a loaner scope for giving to labs for temporary use, or for a new tech. that we hope to hire soon. The reason is that it doesn't have the in-depth data analysis of the LeCroy, and unlike the Agilent 6000 and 7000 series, it's waveform update rate slows to a crawl whenever deep memory is used, or measurements and digital channels are turned on.
The Agilent seems to be the best bang for the buck. I've had a MSO6054 for a few years, and now several of their 7000 series. They maintain high update rates with the always-on deep memory (not quite as deep as Tek, only 4MB when running Normal, 8MB with a single acquisition). The Tek also tends to display persistence artifacts that make you think something is there, but it's not, just persistence from the last acq. So now the MSO7054 is my primary mixed signal design scope. The MSO6054 will be there for a student intern this summer.
You are probably wondering, well why the heck did I buy the Tek? I needed a histogram measurement of some PLL jitter, and the Agilent can't do that. I also mistakenly was still discounting LeCroy as not worthy of consideration.
My feelings on the LeCroy changed due to the following endeavor: First, another lab rat bought a LeCroy because it had more segments to it's segmented memory acquisition than the Agilent. Also, the Agilent can't maintain full sampling rate when more than a few 100 segments are selected. Wierd. So he started selling me on the LeCroy, after defying me and buying one after I tried to steer him toward Agilent.
Then I had a new measurement problem: Measure and optimize in real time the shot-shot energy stability (relative standard deviation) of an optical parametric oscillator, as a function of various parameters--you don't want to know. OPOs are a bitch.
Well the Agilent and Tek can spit out numbers for standard deviation and mean of an amplitude or area measure. Then I have to type them into my calculator to get rel. std. dev. The Agilent accumulates N acquisitions. The Tek has a moving average with configurable count, but an unspecified weighting function that seems to lead to discrepancies vs. the accumulating stats. on it's histograms.
Either of them can get the number with the assistance of a calculator, but neither can give it directly in real time, nor provide a trend plot.
Enter the LeCroy. LeCroy loaned me a 1GHz 104MXi-A for over two weeks. On the third day, I figured out how to make my measurement. The thing can do trend plots of any measurement parameter, such as amplitude. You can set how many past measurements to plot, so that controls the rate at which it rolls across the screen, in conjunction with the acquisition rate.
The you can compute mean and standard deviation (or any other maths) on the trend plots, not just waveforms! That produces another numeric measurement parameter output. That in turn can be put into another trend plot! Magnificent. Then I can do a mean on that, with an indicator bar. So I get three displays of my relative standard deviation measurement: a number, a trend plot, and a graphical bar indicating the average of the trend, sort of like a meter movement.
Sweet!
There is more than one way to set this up as well. It has this amazing "web math" editor that is like LabView. It lets you graphically pipe waveforms, parameters, etc. to measurements, math operations, and trend plots, then pipe those to more, then output the results to measurement parameter displays or math trace displays. That way, you can compute operations on a virtual trend plot, without having to use a visible trace, which are limited to only 8, I believe.
In short, the LeCroy is the best data analysis-oriented scope in the under $20000 class.
The only drawback to the LeCroy is waveform update rate. It simply can't come close to the Tek 4000, which also pales compared to the Agilent (note: Tek DPO7000 is in another class altogether, with up to
250000 wfms/s vs. 100000 for Agilent, but only with 25k samples!). Fortunately for my 10Hz laser pulses, this limitation of the LeCroy won't be an issue.The LeCroy also has these cool "track" plots which are different from trend plots. Tracks are plots of the history of a measurement, time correlated with the waveform being measured. So this can effectively demodulate a PWM waveform, for ex., and plot the pulse width as a function of time, correlated with the actual PWM waveform. Likewise for other modulation schemes.
There are of course many other features in all of these instruments that I haven't yet touched upon.
For general electronic design&troubleshooting, I will be turning first to my Agilents. For tricky measurements with complicated math and multiple stages of computation as well as trend plots, the LeCroy is simply magical.
I don't think I'll be buying any more Teks unless there is something that just can't be done with any other instrument. Unlikely.
I will have a look at Yokogawa next time I'm in the market though.
LeCroy is developed and made in USA, BTW.