Sunday, May 22, 2016

Evaluation of the Signal Hound BB60C Real Time Spectrum Analyzer with SPIKEtm version 3.1.0 EMC Precompliance Software Module

"Sometimes you just know that you are going to like a piece of test equipment before you even see it."

Courtesy: Signal Hound
When my coworkers told me about Signal Hound a few years ago, I had to smile at the name.   A little net-digging told me that Test Equipment Plus (TEP, in Washington State) was making a highly portable, affordable and full-featured spectrum analyzer that uses your laptop as its user I/O - an analyzer that can fit in your laptop bag!

As an EMC Consultant, I was interested.

TEP created the first series of Signal Hound analyzers in 2010 and started doing business under the Signal Hound name in 2014. Since then, they have created a line of spectrum analyzers, including the economical USB-SA44B (less than $1000), the 12 GHz SA124B (at $2000) and the super-fast real time BB60C ($2879).   They also are making a number of tracking and vector signal generators plus numerous accessories designed to be used in tandem with the analyzers. 
I stopped by their booth at the 2015 IEEE International Microwave Symposium in Phoenix, and had to tell them that I really liked the idea of having a spectrum analyzer right in my bag. What a benefit that would be for an EMI-Consultant and his clients!  No more shipping test equipment, test equipment rentals or relying on a dusty old spec-an that a client may have ‘acquired’ decades ago.

So when Signal Hound’s CEO (Bruce Devine) asked me to evaluate their new EMC Precompliance software tool a couple of months ago I jumped at the chance.   Would I?   Of course!

After asking for a favor from my friends at Compliance Testing Labs in Mesa Arizona, I was able to operate the BB60C with the new EMC Precompliance module in the Spike 3.1.0 software in a ‘real lab’.

Unboxing and First Impressions –

The BB60C comes in a box not much larger than the unit itself.  Unboxing it was easy.  I liked the size and weight of the BB60C – just right for portability and heavy enough to feel like a quality product.

I was a little surprised that the unit did not have any way to protect against ESD during packaging and unboxing.   It was wrapped in what appears to be regular non-conductive plastic wrap with no connector caps.   EMC engineers know a thing or two about ESD, so it may be a good plan for Signal Hound to install static dissipative connector caps or use a static dissipative bag as part of the packaging.  The good news is that unit worked great once I got it set up.

Everything Out of the Box

Installation and Setup –
As is the case with most technical folks, I often think of reading the user’s manual as the ‘optional last resort’.  While the user’s manual states that I need a quad core i-Series processor to run the software, my older ASUS laptop has an Intel i5-2450M dual core machine that does not have ‘official’ USB 3.0 hardware.

Fortunately, I was able to resolve this with the help of AJ at Signal Hound. At the end of the day, I had to install the SPIKE software on my wife’s ‘newer’ Lenovo AMD A6-310 machine (a side benefit being that the Lenovo could not be used for internet shopping for a few days as I was evaluating the unit!).

One thing that I ran into while trying to set up the BB60C on my older ASUS was the length of the USB cables.   The BB60C needs both a USB 3.0 port and a USB 2.0 port, the latter presumably for power.  Oddly, my ASUS laptop has a single USB 3.0 port on the left side and all of its USB 2.0 ports on the right side. So, when the USB 3.0 connector was plugged in, the T cable to the USB 2.0 connector was not long enough to reach the USB 2.0 ports on the right side. I had to scrounge for a USB extension cable to connect the USB 2.0 port.  It didn’t matter anyway, because the ASUS was too old.

When I switched to my wife’s Lenovo I had no problems, since it has USB 3.0 and 2.0 ports on the same side. Installation was a breeze.  It was really easy to follow the installation DVD’s instructions and I had a running setup in 15 minutes.

BB60C with SPIKE 3.1.0 Software set up at Compliance Labs in Mesa, AZ

Operation –
Once I got everything working with the Spike 3.1.0 software installed, I felt that the unit was super simple to operate.   I only had to refer to the user’s manual when I needed to install antenna factors and path losses.  

Here are a few things I checked when I first fired up Spike’s EMC module:

  •  Scan speed – the BB60C is fast!  Really fast.  It’s a real time spectrum analyzer after all.   The entire (software-default) sweep from 9 kHz to 1 GHz was less than a second – including any software calculations! 
  • Noise floor – the system has the sensitivity to easily see the FCC/CE class B noise floor, especially if it’s corrected for a 3-meter test distance. It has a rated DANL of -154 dBm/Hz at 10 MHz.
  • Multiple Scan capability – the software allows multi scan and single scan capability with both peak hold and clear write.   Very nice for emissions troubleshooting.
  • Overload - The unit provides an indication of overload if signals are too high.   That’s very important and something I was looking for.
  • Detectors – The unit has the capability to scan in peak and average mode, and allows simultaneous measurements using peak, average and Quasi-peak detection at a single frequency with a very nice bar graph presentation.
  • Bandwidths – in addition to the standard 1,3,10 ‘flat-top’ and -6 dB bandwidth settings, the unit has the 9 kHz, 120 kHz -6dB bandwidth settings necessary for FCC and CE mark testing.
  • Data Presentation - The log-frequency x 10 dB uV/div graph is perfect. I really like the presentation and its auto scaling. No muss, no fuss, just the graph you want.
  • Markers – A necessary ‘nice-to-have’.


First Scan Using the Default Range Table

Did I mention that the BB60C was fast?   Brian Daniel, my good buddy from Orbital ATK, brought over a Signal Hound SA124 that he purchased a couple of years ago to compare with this unit.   It was a night and day difference, since the BB60C is a Real-Time spectrum analyzer with a 27 MHz instantaneous front end bandwidth. 

EMC Software Module Operation - The EMC software module is controlled by the Range Table Control Panel, which gives you ten sweep ranges that can each have their own frequency range, bandwidth, detector and dwell time settings.  It also allows you to set a threshold amplitude value to automatically transfer emissions greater than a certain amplitude limit to a ‘spur table’ (more on that in a minute).  

This is VERY reminiscent of something that I call a sweep plan – which I like to see in a well-written test procedure. All of the scan variables are given and set in one table.

Once set up, the scan is shown on the log-frequency x 10 dB uV/div ‘Frequency Scan Display’.   Since the scans can be run fast and constantly, low duty cycle and short duration emissions are easily captured. If an emission over the set limit is detected, it’s frequency and amplitude are sent to the Spur Table.

The spur table gives you the frequencies and amplitudes of signals above the limit set in the range table. These can be exported to a csv file, or more importantly each signal can be sent directly to the Bar Meter function.  I’ve seen this kind of display on other EMI receivers, and it super-useful for troubleshooting individual emissions.   The Bar Meter shows both the real-time and maximum emissions readings using all three available detectors, including a digitally-derived Quasi-peak detector that automatically changes its charge time constant based on the emission frequency (per CISPR 16.1 & ANSI C63.2). 

Courtesy: Signal Hound

Cool Bar Graph Display

Once you make Bar Meter measurements, you can send your data to a “Meter List”, which will give you a listing of the emissions measurements taken using all three detectors.  The Meter List is also exportable as a csv.

One of the nice things about the EMC precompliance software is that its totally modular.  You can set up a Range Table and scan all day if you want to. Once you think you have a passing configuration, you can go ahead print the scan data, or you can measure each emission using the bar graph and then export it using the Meter List.  There are a lot of options depending on your need and troubleshooting methodology.

A good view of the SPIKE EMC Precompliance Software with a noisy comb generator and the chamber door open

One thing that can use some more work is the output.   Using the print function basically gives you a screen shot.   I’d like to see more of a test datasheet, with a header, date/time and notes field. But is that really important for precompliance software?

The Comb Generator in the Chamber

More on the BB60C
By the way, the BB60C can do a whole bunch more in other parts of the software.  Here are just a few:
  •     Session recording
  •        Waterfall and 3-D Persistence displays in Real time mode (see Figure below)
  •        Zero Span
  •        Scalar Network analyzer mode using a tracking generator
  •     Digital Demod & Modulation Analysis
  •     Audio Receiver
  •     I/Q captures
  •     Channel Power

courtesy: Signal Hound
Text Box: Courtesy: Signal Hound Users Manual
Incredible for less than $3k!

Final Thoughts
Throughout the evaluation, I had absolutely no issue with the software hanging up or lagging.  All measurements I took seemed very reasonable.   The EMC module is well written and easy to learn.  Honestly I wish I had more time in the lab to play with the unit!
I’m really looking forward to seeing the final version of the EMC Module.  I have to say that I would buy this unit today! 

 - Glen