When it comes to debugging a design that combines high-speed serial signals with RF, a mixed domain oscilloscope (MDO) is more than the sum of its parts. You can quickly switch between time and frequency domains to track down the root cause of problems in a particular design.
One of the things we often hear from engineers is: “All that sounds great, but I wouldn’t use a built-in spectrum analyzer everyday, so why should I pay for functionality I don’t need.” When we hear this or something similar come up, two points come to mind that I thought would be helpful to discuss further in this post.
First, it may be true that you’re not using a spectrum analyzer on a daily basis today. But there’s a good chance you will be in the near future. This is because of the integration of wireless into everything, well not everything but just about…wireless is built-into phones, laptops, cars, even watches have wireless. In fact by 2026, experts predict there will be eight mobile devices per person on Earth. So if you think wireless is everywhere today, get ready for the future.
The next point is more involved, but the bottom line is clear – MDOs are a great value. Straight up oscilloscope vs. oscilloscope, Tektronix MDO4000s and MDO3000s cost about the same as equivalent scopes from other major test and measurement vendors such a Keysight (formerly Agilent) and their InfiniiVision series. To break it down further, this means you’re getting a highly capable spectrum analyzer for free. Hard to argue with free.
When you go to the Keysight website, it directs engineers looking for a mid-range scope to Basic and X-Series Signal Analyzers. If you want RF, you’ll also need to consider all the additional costs you’ll incur on top of Agilent’s 3000 and 4000 X-Series DSO and MSO scopes.
The table below shows how the scopes stack up by the numbers. Note that although the MDO4000 starts at $9,500, this comparison is based on the 500 MHz model.
| Tektronix MDO4054B-3 Mixed Domain Oscilloscope | Agilent/Keysight MSOX4054 Oscilloscope, N9320B BSA Spectrum Analyzer |
Oscilloscope | MDO4054B-3, $17,400
| MSOX4054, $17,066
|
Spectrum Analyzer | (Built-in FREE)
| N9320B BSA, $ 8,468
|
Price | $17,400 | $25,534 |
Here’s how the MDO3000 stacks up to the Agilent 3000 X-Series DSO and MSO Series.
| Tektronix MDO3012 Mixed Domain Oscilloscope + MDO3SA option | Agilent MSOX3012A Oscilloscope, N9320B BSA Spectrum Analyzer |
Oscilloscope | MDO3012 + MDO3MSO upgrade (16 digital channels), $4,850
| MSOX3012A, $4,554
|
Spectrum Analyzer | Add MDOSA option FREE until 9.26.2014 (valued at $2,500)
| N9320B BSA, $ 8,468
|
Price | $7,350 | $13,022 |
Beyond lower cost of entry, a great benefit to MDOs is ease of use for RF. I can’t tell you how nice it is to have multiple instruments in one, not to mention the extra bench space. For more details on some of the benefits of the integration of instruments, check out the “Fundamentals of a Mixed Domain Oscilloscope” application note.
Since publishing the above blog, Tektronix is currently offering a free upgrade to 3/6 GHz spectrum analyzers and a free bundle of software applications on mixed-domain oscilloscopes. Check out the details here and save away!