Jonathan Newell explores a test system for an automatic emergency call module from Harman, which depends on multiple wireless and cellular technologies.
Best known for its audio and infotainment systems, Harman also supplies high level in-vehicle connectivity systems and has developed a platform for the automotive industry to conform to the imminent pan-European eCall system – which will soon be required on every new vehicle shipped in mainland Europe.
The eCall platform is a potential lifesaver – its prime function being to detect a vehicle impact and automatically call the emergency services, passing on the vehicle’s GPS coordinates and other parametric data, as well as opening a voice channel.
Potentially, the platform can also be used for other functions within the vehicle, such as infotainment, telematics and vehicle monitoring, a complex set of requirements calling on multiple wireless communication technologies, as well as cellular systems.
To test the platform’s capabilities on all these technologies, including WLAN, Bluetooth, GPS and cellular, Harman selected equipment from NOFFZ Technologies and National Instruments (NI), who developed a test bed that could be used with sufficiently fast cycle times to meet the needs of automotive production volumes.
The UTP 9010 from NOFFZ formed the basis for the test bed, enabling a multiple DUT (Device Under Test) configuration. The test system can accommodate 4 DUTs in parallel connected using pins, a moveable block connector and a partially shielded RF antenna.
In this configuration, the test system combines all the requirements for performing end of line tests at the board level including flashing, functional and RF tests.
To do this, a number of PXI and PCI cards are used for audio, voltage and current measurements. These are deployed, together with a signal conditioning unit for routing the measurement signals and test antenna diagnosis functionalities, as well as performing sleep mode current measurements and digital control.
Underlying the test hardware from NOFFZ is the National Instruments Wireless Test System (WTS), using a PXI vector signal transceiver and the latest Intel Quad Core processor for achieving the required test speeds.
The WTS combines a vector signal analyser and a vector signal generator in a single software designed instrument. Having undergone technology improvements since its initial launch in 2012, the WTS has the adaptability and ease of programming capability needed for rapid test development systems such as that used by Harman. The signal processing algorithms used in the WTS reduces test times and optimise measurement results.
At NI Week in Austin earlier this year, National Instrument’s Senior Marketing Manager, Alejandro Buritica demonstrated the simplicity with which the company’s TestStand test management software, which has a library of ready-to-use routines to make it simpler to deploy, was able to be used for writing parallel test sequences for wireless devices. In the demonstration, Buritica programmed tests for a similar bank of DUTs as used in the Harman system.
As Manuel Bogedain of NOFFZ explained, the TestStand based NOFFZ test execution front end is capable of testing four RF DUTs fully in parallel. “The NI WTS is a multi-up, multi-standard RF measurement device which is fully capable of testing all the eCall radios like cellular, Bluetooth, WLAN and GNSS,” he said.
At the NI event, the eCall test platform won the Consumer Electronics Test category in the 2015 Engineering Impact awards and Harman’s Senior Manager of Test Engineering, Ehab Beshay was there to receive it. “This test system reduces test times by as much as 30%, compared to existing single DUT testing meaning fewer test systems required to meet production demands,” said Beshay.