Mobile Apps Support Communications Test, Data Acquisition
Mobile devices are becoming serious engineering tools as apps emerge that handle design and test functions in communications and related applications areas. Indeed, you can choose from among hundreds of engineering apps at the Android market or iTunes store. Many of these are reference works and calculators. You no longer need access to a shelf of books or even your desktop computer to look something up, and you can forgo the stand-alone engineering calculator that you need for portability and to overcome the limitations of the calculator that comes with Windows.
The IEEE, for example, offers a wireless dictionary app, and The Engineers’ Club provides a calculator that helps you design with waveguides. To help you keep in touch, the Audio Engineering Society has an app that brings you news of its conventions and conferences as well as podcasts summarizing the AES Journal. You also can search for products or jobs. NXP allows you to search for and buy any of its more than 10,000 standard parts using your Android. Also for Android, Dice offers an engineering job-search app. And Agilent Technologies has a power-supply catalog for iOS devices.
Agilent offers a number of calculators for iOS as well:
- Printed Circuit Board (PCB) Trace Impedance Calculator computes the characteristic impedance and sizes of typical PCB trace geometries. Users select a PCB geometry and enter values for relative dielectric constant, known dimensions of the structure, and impedance; they then press the button next to the unknown parameter to calculate the result.
- MicroWave Calculator consists of a directivity error calculator, a mismatch error limit calculator, and a ratio-to-dB calculator. A spokesperson calls the app the 21st century’s version of the old reflectometer slide rule calculator.
- Engineering Calculator is an interactive application that allows users to input the required data, and results are shown in the form of graphs, tables, animations, or other meaningful representation. It solves basic electrical engineering equations.
In addition, Agilent offers a Tips and Tricks App for its 2000/3000 X-Series Oscilloscopes, which supplements manuals and quick-start guides and provides tips on oscilloscope basics for beginners along with more detailed tips and tricks for advanced users.
But the apps show most promise for increasing productivity in engineering when they enable mobile devices to play an active role in design and test functions.
The Device Is the Instrument
In limited cases, the device itself can become the instrument. For example, Speedy Spectrum Analyzer can turn an Android phone into an audio spectrum analyzer (Figure 1). Of course, smartphone manufacturers don’t tend to publish response curves for their devices’ analog front ends, so unless you care to determine them yourself (accounting for factors such as temperature variations and battery level), you’ll need an alternative solution unless your requirements for accuracy and repeatability are modest.
Figure 1 A Above Middle C Plus Some Harmonics Rendered on an Android Phone
As an alternative, vendors offer modules that, combined with an app, turn your mobile device into an instrument without the I/O limitations of the device itself. For example, Redfish Instruments’ iDVM is a module that wirelessly links to an Apple device to form a wireless multimeter. And Oscium’s WiPry-Spectrum turns your iOS device into a 2.4-GHz ISM band spectrum analyzer (Figure 2) that can pry into your Wi-Fi environment to detect and avoid noisy channels. Oscium also offers a dynamic power meter, a power-meter/spectrum-analyzer combination, and a mixed-signal oscilloscope for iOS devices.
Figure 2 2.4-GHz WiPry-Spectrum Spectrum Analyzer App and Module for iOS Devices
Courtesy of Oscium
App Helps Test the Network
It is fitting, perhaps, that one app targets test of the wireless network infrastructure that mobile devices rely on. In October of last year, JDSU announced an Android smartphone app that helps wireless carriers conduct LTE network analysis using JDSU’s drive-test system, a flexible, customizable, and scalable system for the optimization of wireless networks and data services. The app integrates with the system to simplify LTE RF service verification and troubleshooting while reducing network management costs.
The app allows engineers to perform real-life tests; in the field, they can collect, record, play back, and transfer data from network trouble spots to an operations center for analysis and resolution. The app automates the collection of data reflecting performance of voice calls, file-transfer uploads, file-transfer downloads, and browsing. Data is geolocated using the phone’s global positioning system.
Serving Design and Test
Apps can help you evaluate your designs as well as serve in test applications. One example is Xilinx’s Pocket Power Estimator (PPE) app (Figure 3) for iPhones and iPads, which assists engineers in estimating the power consumption of designs based on Xiliinx 7 Series 28-nm FPGAs. In fact, a key advantage of the 7 Series parts is their capability to deliver maximum performance at minimal power.
Figure 3 PPE App for Estimating 7 Series FPGA Power Consumption
Courtesy of Xilinx
Xilinx says its 7 Series FPGAs require about 50% lower total power, on average, than earlier-generation 40-nm devices, thanks in part to the HPL (high-performance/low-power) process technology offered by its foundry partner TSMC. The power savings break down, on average, to 65% lower worst-case static power, 25% lower dynamic power, 30% lower I/O power, and 60% lower transceiver power.
But customers want more specific figures on the power consumption specs of their own designs, based, for example, on the SerDes transceivers, DSP blocks, memory blocks, and logic gates they want to incorporate into their designs. The PPE app takes into account these aspects of total power consumption to enable designers to easily obtain a high-level estimate of power usage by functional block and how it compares to other Xilinx or competing devices.
A Xilinx spokesperson says the app began as a tool that field application engineers and sales engineers could use to start a conversation with customers and provide some meaningful metrics about power consumption without having to fire up their laptops. Customers were intrigued by the app, and Xilinx decided to make it available to them. For more complex and detailed power analyses, designers would use the ISE® Design Suite’s XPower Estimator (XPE) and the XPower Analyzer (XPA) tools running on a workstation.
The PPE includes reference examples that designers can use as starting points to customize to their own specs. The first release of the app incorporates design examples for the wired and wireless communications markets while future releases will have additional market-segment examples and support other smartphone platforms.
Mobile Apps for DAQ
While apps like the waveguide calculator and spectrum analyzer as well as the JDSU and Xilinx apps focus heavily on communications applications, data acquisition, too, is getting attention in the apps space. Redfish Instruments’ multimeter app can serve as a datalogger, for example, and big companies are getting into the business as well.
Agilent Technologies is one such company, and Neil Forcier, an applications engineer with Agilent’s system products division, recounted the use of mobile devices in DAQ applications in a feature article in June.1 He wrote, “Smart devices offer a portable and interactive way to access information and data wirelessly from almost anywhere. They access information and data through Ethernet using a provider’s cellular network or a Wi-Fi connection. As smart devices continue to become a bigger part of our digital and wireless lives, they will find their way into the test and measurement industry,” he concluded.
In a recent phone interview, Forcier said Agilent’s 34972A DAQ app (Figure 4) grew out of a grass-roots effort. He said he began programming in iOS as a hobby but realized the operating system had network sockets and should be able to communicate with an LXI instrument like the 34972A. He said his initial efforts led to other grass-roots efforts among Agilent engineers interested in using smart devices to control instruments. He said getting the app released took about as much time as designing the app because Agilent had not established standards for software based on Apple’s mobile device platform.
Figure 4 iPhone App for the 34972A Data Acquisition System
Courtesy of Agilent Technologies
The 34972A DAQ app provides a means to control and monitor Agilent’s 34972A DAQ switch unit with a 34901A 20-channel multiplexer module and/or with a 34902A 16-channel multiplexer module. It supports four main features for controlling and monitoring a 34972A:
- Setting up and monitoring measurements on a 34901A or 34902A module.
- Creating and running scans using a single module or multiple modules.
- Controlling scans that were started using the app or externally by another means such as the 34972A’s front panel or web interface.
- Retrieving measurement data from memory.
Forcier said the 34972A was a good target for a mobile app because it can run on its own—it need not be continuously connected to a host computer. With wireless devices, he said, you don’t always have guaranteed connectivity. The mobile device can check in with the DAQ system infrequently to read data or change a setting—for example, when the engineer carrying the mobile device changes planes in an airport.
Right now, Forcier said, “It’s blazingly obvious that iOS and Android are the top platforms” for smartphones and tablets. But things can change quickly in the consumer electronics world. He said he is monitoring HTML5 developments, which may enable the establishment of a web-based platform that is transparent to the operating system, but he suspects that the Apple and Android camps might resist such an effort.
Forcier noted that cloud computing is becoming an important adjunct to mobile apps. The cloud, he said, can be a great intermediary between smart devices and instruments, allowing them to share data. He cited the Dropbox file-sharing service, which could let engineers share spreadsheets containing test data wherever they are located and whether they are using a desktop computer or mobile device.
Navigating Rapid Device Turnover
Another company pursuing a mobile-device strategy with respect to data acquisition is National Instruments. P.J. Tanzillo, senior group manager for product marketing at NI, noted that in the early days of PDAs, NI provided a module that supported portable data acquisition and remote monitoring. The big challenge, he said, is that the mobile device market is changing so quickly it’s difficult to predict what will happen in a year. The early PDAs such as Palm devices are gone, and Hewlett-Packard acquired and is discontinuing the WebOS successor to Palm OS. Just a couple of years ago, he said, BlackBerry would have seemed to be the platform of choice.
But as does Forcier at Agilent, Tanzillo sees Android and iOS as the dominant platforms today, and the company is applying resources to each platform. NI has chosen the iPad as the initial device to host its new Data Dashboard for LabView app (Figure 5), which is rolling out this month.
Figure 5 Data Dashboard for LabView App, Running on an iPad
Courtesy of National Instruments
Tanzillo said that unfortunately reuse between the iOS and Android platforms is low because of consumer expectations and for technical reasons related to the programming tools available for each platform. To make a nice iOS app, you have to use the native iOS user-interface paradigm, which differs from Android. Nevertheless, he said, NI will be targeting both platforms and addressing four potential use cases: data acquisition (and especially wireless data acquisition), remote monitoring and control, reference (documentation replacement), and development augmentation.
This last case, Tanzillo said, gives engineers another screen or another interface to augment their desktop development environment. “From an engineering perspective,” he said, “if you are using LabVIEW or Visual Studio and you want context help on a certain function or block, you can imagine that help popping up on the iPad as opposed to on your [workstation] screen so you don’t lose that screen real estate.” He added that multitouch technology shows promise for facilitating navigation through blocks in a LabVIEW program.
When asked if there had been any resistance within NI to working with mobile devices, Tanzillo said, “We like being on the edge.” NI, he said, is a company that built its technology around the PC when it was emerging, and the company wants to be in the forefront of understanding where technology is heading. He noted that Windows 8, due for release this year, has many tablet-centric features, adding, “When Apple and Microsoft are both throwing their weight behind [tablet technology], you can believe it’s going to be there for a while.”
Mobile devices can’t do everything, though. Tanzillo said that it’s important to distinguish between content creation and content consumption when evaluating a mobile device for a specific application. You might consume content all day on a mobile device, he said, but you’re unlikely to be creating as much. For example, he said, you might edit a PowerPoint presentation on a handheld, but you won’t create one from scratch. The conclusion, he said, is that we are not in the post-PC era—it’s PC++ with mobile devices providing PC augmentation, not replacement.
1. Forcier, Neil, “Controlling LXI Instrumentation With Smart Devices,” EE-Evaluation Engineering, June 2011, pp. 28-33.