Fake heads and robot probes: testing smartphones prior to launch

Inside the Silicon Valley lab of UL, where smartphones undergo testing before they go on sale

IDG

IDG

On the shelves of a laboratory near San Francisco sit tanks and tanks of mysterious-looking liquids. Labels identify some as simulations of human heads, while others relate to muscles.

It sounds like the ghoulish headquarters of a mad scientist, but it isn't. It's the Silicon Valley offices of UL, a product testing organisation previously known as Underwriters Laboratory, and these liquids play an important part in smartphone safety.

You might not know UL, but you can probably find its logo on a number of products around your home.

20170418 101250 1 Martyn Williams

Two UL logos are seen on a computer power supply. The company tests products to ensure they meet safety requirements.

Manufacturers contract with the company to run tests and ensure products meet safety and regulatory guidelines. This laboratory is used to test for electromagnetic radiation coming from phones.

Electromagnetic radiation is emitted by all electronic devices. You'll sometimes experience it as interference on a radio or television, and in the context of smartphones, there are legal limits on how much RF (radio frequency) radiation they can emit. The standard is how much a human body can safely absorb.

That standard is based on the specific absorption rate, or SAR, and that's where the liquids come in.

20170413 101400 3 Martyn Williams

Containers of liquid designed to simulate the human body sit on shelves at UL in Fremont, California, on April 13, 2017.

"The liquid is designed to emulate the electric properties of the human body," said Dave Weaver, program manager of the SAR lab. There are different liquids that simulate tissues in muscles and the head.

His lab has four testing stations that each sit above a different mold, some to simulate the head and others to simulate the torso. The liquids are poured into their respective molds and a cellphone is placed underneath, and with a whirr of electric motors, robotic arms spring into action.

20170413 101350 1 Martyn Williams

A robot controlled measuring probe sits in a vat of liquid as part of cellphone RF testing at UL in Fremont, California, on April 13, 2017.

At the end of each arm is a sensitive probe that measures the strength of the RF field at its tip.

"The probe is essentially a very small antenna," Weaver said. "It dips into the liquid and measures the electric field strength in the liquid, and from there we can calculate the dose, how much energy is absorbed by the user."

By using a liquid, the probe can be placed at varying distances from the cellphone under test so the field can be determined near the skin and deeper inside the body.

20170413 101356 2 Martyn Williams

A measuring probe sits in a vat of liquid as part of cellphone RF testing at UL in Fremont, California, on April 13, 2017.

The lab tests a range of products, including smartphones, laptops and wearable devices.

"A watch, for example, could take maybe a day, because there’s not much in it," said Weaver. "A complex cellphone could be several weeks, using multiple systems at a time."

Whereas 15 years ago, a cellphone connected to just two or three frequency bands, today a phone like the iPhone 7 connects to more than 20 LTE bands, a handful of bands for older cellular technologies, two Wi-Fi bands and Bluetooth, so the testing takes a long time.

To generate these signals, a communications tester sits on a nearby shelf. It can imitate every wireless network the phone is likely to come into contact with and prompt the phone to generate signals of different strengths.

20170413 102655 1 Martyn Williams

A piece of measuring equipment used as part of cellphone RF testing at UL in Fremont, California, on April 13, 2017.

The result of all this work, hopefully, is an approval from UL that confirms the product is within SAR guidelines. The results are usually given on the safety and regulatory pages of manuals for the products -- the bits that almost nobody reads. Apple has them grouped on a website.

The SAR limits are set in the U.S. by the Federal Communications Commission and in Europe by European Committee for Electrotechnical Standardization (CENELEC).

This isn't the only testing a phone must undergo before it hits the shelves. It needs to be checked to ensure it's compatible with various cellular technologies and doesn't cause interference to other users. Cellular carriers will often also put handsets through weeks of testing to make sure they work as advertised.

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Martyn Williams

IDG News Service
Show Comments

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?