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 

Tuesday, November 3, 2015

2015 Aerospace Testing Seminar -

Presented my paper on "Evaluating Receiver EMC Safety Margins Using the Through-Antenna Radiated Emissions Test Method" at the Aerospace Testing Seminar in LA last week.

Thanks to my friend Mike Todd from Orbital ATK for taking my photo!


Giving my presentation at the ATS seminar.  It doesn't look like it, but there were almost 150 attendees in the meeting room! 


Wednesday, March 25, 2015

What I learned at the 2015 IEEE EMC Symposium - How High Power Electromagnetic Effects Can Change Our Lives! 


I had the pleasure of attending the 2015 IEEE EMC Symposium in Santa Clara last week.  I have to say that it was one of the better symposia I have been to – loaded with thought-provoking and informative speakers.  But the keynote speech was especially interesting.

It was so interesting, that I thought I would blog about it!

The keynote speech was delivered by Dr. Thomas H. Lee of Stanford University.   Dr. Lee’s style is very down to earth, with amusing engineering ‘sayings’ and remarks.   Even so, he chose a very serious subject to speak about – the vulnerability of our digital world to high power electromagnetic effects. .

Dr. Lee explained that our planet now contains as many cell phones as humans.   Amusingly, he also mentioned that there are 10 times the number of transistors made each year than ants on Earth! (yes, ants. - others have estimated even higher).  We all know that our economy and in many ways our lives are dependent on the internet, and we are becoming more and more connected every year.

But history has shown that we may be vulnerable!

Coronal mass ejections (CMEs), or massive bursts of gas and magnetic fields from our Sun, have been observed as far back as 1859. That CME – also known as the Carrington event – induced one of the largest geomagnetic storms on record.  Aurora could be seen as far south as Hawaii!  Telegraph systems all over Europe and North America failed, and even gave telegraph operators electric shocks. (Ouch!)  Telegraphs operators could continue to receive and send messages despite having disconnected their power supplies.

Another strong CME was detected in 1989. It caused a transformer failure on one of the main power transmission lines in Quebec.   Six million people lost power for nine hours or more. It cost Quebec $2 billion to repair and upgrade their system! 

In 2012, a Carrington-Level Event barely missed Earth.

Whew! 

Dr. Lee also spoke about the July 9, 1962 “Starfish Prime” high altitude nuclear test near Johnson island in the Pacific. It was a ~1.5MT detonation at an altitude of about 250 miles.   This test caused an Electromagnetic Pulse (EMP) that was far larger than expected, and drove monitoring instrumentation off the scale. The EMP knocked out about 300 streetlights, set off numerous burglar alarms, and damaged a microwave link 900 miles away in Hawaii!  Many folks in Hawaii were able to see the blast, possibly because the event was advertised in the newspaper!  Since it was high-altitude, the blast also formed radiation belts around the earth.  These man-made radiation belts eventually crippled 1/3 of all low earth orbit (LEO) satellites that were in orbit at the time.

Needless to say, CME and EMP events could have a devastating effect on our connected society. In addition to the internet and cellular infrastructure, the ever expanding Smart Grid and the machine to machine connectivity of the Internet of Things are all potentially vulnerable.

As EMI engineers we are on the front line.

Many of us EMI engineers have designed circuits to be lightning or EMP resistant.  Fortunately, there’s a technical committee (TC) within the IEEE EMC Society that specializes in High Power Electromagnetics. (TC5 – Chaired by Dr. William Radasky).   Because of Dr. Lee’s interesting speech, I made time to sit in on the TC5 meeting. 

TC5 is not only concerned with CME’s and EMP but is also the IEEE’s technical committee concerned with other high power phenomena, such as Lightning, Intentional EMI (IEMI) and Electrostatic Discharge.

I learned that there are six working groups presently in process of looking into existing lightning standards.   There has been work by the power systems council Cigre stating that levels in present lightning standards may be as much as 10x too low!   That includes our technical standards for commercial aircraft!!

I also learned that Intentional EMI (IEMI) is a ‘hot topic’. For those of you not familiar with it, it’s defined as “Intentional malicious generation of electromagnetic energy introducing noise or signals into electric and electronic systems, thus disrupting, confusing or damaging these systems for terrorist or criminal purposes”.  That’s right, the bad guys are using EMI against us! 

There were 6 presentations about IEMI at this 2015 symposium, all of which were well attended by more than 40 people.  Dr. Radasky spoke of one case where a security video camera was intentionally interfered with by criminals.  When radiated, the image froze – which if you think about it, that’s the worst thing that could happen.   One of the outcomes of TC5 was the publication of IEEE 1642, the “Recommended Practice for Protecting Publicly Accessible Computer Systems from Intentional Electromagnetic Interference (IEMI).


My impression is that’s it’s a good thing we have such a great deal of interest and activity on issues that could affect our very lives!   It’s a great time to be an EMI engineer!

Tuesday, February 10, 2015

                                       

Tuesday, January 13, 2015

What to do just before you go for EMI testing….

The Pre-Test Setup – often forgotten but so important!

In many cases, companies don’t have an in-house EMI test lab and have to travel for hours to find an open lab that meets their needs.  Some larger companies have in-house labs, but they are often swamped and may be difficult to schedule.  At the end of the day, lab time is costly and it’s important that you make your time in the EMI lab count!   

After months of design, assembly and integration, deadlines approach. Your ‘green-light’ product development schedule is a distant memory and as an engineer, it’s all you can do to get the hardware working, schedule a lab, and ….go!

But…. STOP!  As an EMI lab manger I’ve seen it all too often - Incredible as it may seem, electronic systems are often fully integrated for the first time when they are set up for EMI!  Sometimes days are wasted unboxing hardware, trying to install cables and connectors, and getting the system working while in the lab. And sometimes, it doesn’t go well. 

Set it up before you go! 

Before leaving for the lab, remove your entire system from the engineering development bench and set it up as you would in an EMI lab. 

One company I worked for had an unused EMI test chamber that was mostly used for storage when I arrived. That was an opportunity for me to establish a pre-test setup process, which saved countless headaches when I ultimately reached the outside lab.  Here are some of the highlights:

Place your hardware on a test bench – just as if it was in a lab. 

For MIL-STD and Aerospace EMI tests, that usually means a conductive bench.   That may be the first time that all hardware is ‘tied-together’ to a common ground.  This not only helps resolving issues like unforeseen ground loops, but will give you an opportunity to check your hardware bonding. Remember that MIL-STD and Aerospace EMI tests usually require bonding to the conductive bench to simulate the actual application, so if there are special fixtures needed to bond your hardware to a vehicle frame, now’s the time to use them and try them out.  This is the time to get out that 4-probe ‘Bonding’ milliOhm meter to make sure that the hardware meets the bonding requirements.   Measure from each box to the conductive surface, then across each critical interface. This will keep you from being surprised by an errant paint job or missing/ill-fitting hardware. Commercial companies will want to set up the equipment on an equipment cart similar in size to one provided by the lab.  (Find and …) Install all peripherals and loopback connectors, making sure there’s room on the cart. 

Connect each test cable as it will be connected in the lab. 

Again, MIL-STD and Aerospace companies will want to check connector to box and cable shield to connector bonding. Know the lab’s bench size and layout, and make sure that the cables can be run along the front of the bench as required in the test procedure.  Commercial companies will want to connect all interface cables leading to peripherals or loopbacks. Don’t guess that the lab will have a particular cable – even if it’s common.  It’s good to bring all cables with you! 

Simulate each interface cable’s path through the chamber wall.  

For MIL-STD and Aerospace tests, I always recommend using filter pin connectors or fully shielded cables when penetrating a chamber wall.   Use both if you can get away with it.   To make the transition to a lab easier, it’s best to establish a ‘standard’ cable penetration panel and use it in your pre-test setup. Ground the cable shields (usually through the penetration panel) to the common bench top ground, providing a path for the shunt capacitors in the filter connectors.  It’s better to know that an interface will have issues with shunt capacitance before you set up for the final test! 

LISN’s/LSC’s/ISN’s etc… 

Be aware that power inputs will be attached to Line Impedance Stabilization Networks (or LISN’s) when under test. I was lucky when I inherited the unused lab – it had a nice set of LISN’s already in it. Put them in place in your power lines to make sure that your system will power up properly. 

A Caution to Space Companies:  
You probably already know that flying heavy series inductors isn’t very cost effective from a launch standpoint.  A LISN can have 50uH of series inductance. Installing a 50 uH LISN in series with each power lead can destabilize a switching power supply – and can lead to disastrous results! Be sure your power system can handle the LISN inductance before you power on. 

Power up and operate your system – after it’s set up.  

Software and functional testing are often the biggest problem when you first arrive at the lab, and finding problems before you go is often the biggest potential time saver!  Go through the functional test just like it’s planned in the test procedure.  I have all too often heard the words that “it was supposed to operate that way….” right after the equipment was powered on. Don’t guess – try it.  Remember that some EMI scans can take a long time.  Take equipment heating and duty cycles into consideration.  Also, EMI tests will want to have everything running at the same time, with fast cycle times.  This reduces susceptibility/immunity cycle times and allows for better observation of emissions.  Hopefully, properly designed EMI test software has been created by this time in the design cycle! In any case, run the box before you go!

Pack it and Ship it! 

I’ve seen companies with very complex setups install their equipment on a test bench in their development labs – and then ship the entire bench (including EUT, Cables & all) to the lab!  What a great idea! 

So unless you’re that company, take good photos, label everything, carefully place all your equipment in boxes and ship.   The same folks that were a part of the pretest setup should be at the lab when the equipment arrives! 

One advantage I had when using this approach is that I used the old EMI chamber (and its bench) to ‘store’ the test cables, loads and other miscellaneous bits and pieces when I received them.  I was able to slowly build up the test setup until the day the high value hardware arrived.  


Take it from someone that’s seen it. If you do nothing else, do this. 

Friday, October 31, 2014

Thinking about an EMI precompliance lab?


Maybe it’s the economy or just random chance, but it seems like many of the companies I’ve talked to recently are looking at creating some sort of in-house precompliance test capability.   It’s a good idea to save precious time and money before testing ‘for score’ at an outside lab and it certainly makes sense for companies who have to go far and wide to find an independent lab to run their tests.

Many folks tell ‘horror’ stories of company’s having to stay at an outside lab for weeks, just trying to troubleshoot failures!  Often, these labs are out of town and have limited schedule openings.  But what sort of pre-compliance capability should a company buy?  

Pick the right tests 

It can safely be said that most EMI problems are found during radiated emissions (RE) testing.   That’s usually true for both commercial (FCC/CE and MIL-STD/Aerospace testing).   But that’s not always the case – and it’s not necessarily the only test that should be a focus for precompliance.
For instance, high-rel equipment that needs ‘five-nines’operating reliability can’t be bothered by transients like EFT or ESD. (See methods EN61000-4-4 and EN61000-4-2).   ESD is especially insidious, since it is often ‘blamed’ for several transient susceptibilities without real data to support the claims.  A simple ESD gun and bench can be a cost effective way to verify your designs.

Also, having the equipment to perform power line conducted emissions is often only a few dollars more than a radiated emissions setup – and can really help your power supply designers feel better about the product before it goes out for formal test.

Look at your company’s test results from the last several design cycles.   Make a judgment of which methods cause the most troubleshooting times.   RE is usually picked as a minimum for a precompliance lab, since solving the RE problem can often systemically resolve other failures – but don’t limit yourself to it!

Set a Budget 

As a former department manager, I have been on the other side of the fence, where super smart engineers came to me asking for the company’s (limited!) resources.  Your managers are going to expect a positive return on investment (ROI) – and you need to make a super clear argument so they can pitch it to the top brass come budget-setting season.  Here are a few tips:


  • This one’s kind of obvious: Count up the total days spent at an outside lab troubleshooting a problem. Multiply that by the per day lab rate.  If your outside lab charges $2500/day and you spent 10 days troubleshooting at that lab last year, there’s $25,000 of your company’s precious dollars going out the window. Add any per diem employees may have charged.  Generally, a company will want to recoup in internal CAPEX expenditure in 5 years. That’s going to give you a VERY SOUND argument for spending at least $2500 x 5 or $12,500. Scale up or down as appropriate – and be sure to take new product design projections into account.  If the company wants to expand into a new market and generate 5x the design since last year, that’s a good multiplier.
  • Far less obvious but more important are opportunity costs and the development of intellectual property. Time to market and meeting schedule are often paramount. I knew a company that had a design slogan:  ‘build a little – test a little’.  It really worked.  Having an internal capability of verifying designs that may be reused among many different products/programs at an engineering level reaps huge rewards.   It increases the company IP. At the end of the day, having solid EMI design guidance can spell the difference in the marketplace.  If a company looks at EMI and one of those ‘black magic tests’ that has to be ‘suffered through’ instead of being proactive, it prognosticates its own failure.
  •  Compare EMI to other environments – I still have a hard time comprehending how much many companies focus on Thermal, Vibe, HALT/HASS or other environments, yet are reluctant to spend any capital on EMI.  Often upper management looks at EMI as a single test and asks the question: How much does an EMI lab cost?  I’m here to tell you that I’ve spent over a million dollars on an in-house well-equipped EMI lab.   Twice.   BUT, as we are going to explore in the future, it’s not nearly as costly to develop a precompliance setup that’s targeted to the right tests – for much less than the fleet of $100k/ea thermal chambers that seem to line many engineering labs.

Equipment Selection

In future posts, we’ll examine the kind of equipment you should buy. Do you buy new or used? What may you already have in your inventory? Spectrum analyzers/receivers, antennas, test chambers, troubleshooting equipment – are all part of the equation.   Stay tuned for much more on this subject… 


Wednesday, October 1, 2014

Southwest EMI will be on the air soon - with a new Blog covering EMI and related issues in the Desert Southwest.     Get ready!!!!