Testing today's consumer electronics means spending a lot of time up front validating the design. The proliferation of standards in consumer electronics has made interoperability better but testing more challenging. Test and instrumentation vendors are creating tools to test compliance and interoperability against specifications, helping designers cope with complex interfaces such as high-speed serial interconnects and higher-level protocols.
Some specifications are tailored expressly to consumer electronics devices. The Mobile Industry Processor Interface (MIPI) Alliance (www.mipi.org) has created several specifications focused on the interconnect between functional blocks in a mobile device. The Camera Serial Interface (CSI-2) is a low pin count, high-speed serial interface between the camera silicon and the device processor. Similarly, the Display Serial Interface (DSI) connects the LCD display to the processor. Each specification defines a D-PHY with signaling characteristics and protocols supporting data rates as high as 1 Gbps.
Jean Manuel Dassonville, product manager for digital wireless test products at Agilent Technologies, states that, ‚ÄúInterfaces like the MIPI D-PHY variants are difficult to analyze with a general-purpose signal analyzer.‚Äù Instead of just looking at signals, packet-based analysis is needed. Additionally, both stimulus (pattern generation) and analysis (decoding traffic) are helpful to designers.
Agilent has taken the approach of putting the specifics of stimulus and analysis into probe units, allowing a logic analyzer mainframe to support various functions. For MIPI D-PHY testing, Agilent offers the N4851A Digital Acquisition Probe (Figure 1) and the N4861A 800 Mbps Stimulus Probe, both of which connect to a 16800 or 16900 logic analyzer. Other probe solutions include the N4850 and N4860 for DigRF v3, an interface between the RF and baseband blocks. Designers can mix and match probes to suit their testing needs.
LeCroy has gone after a similar problem for more familiar standards: Ethernet, USB, PCI Express, Serial ATA (SATA), and Ultra-Wideband (UWB). The company‚Äôs QualiPHY automated serial data compliance test framework offers guided test setup and automated measurement capability for high-speed serial interface compliance testing using an oscilloscope outfitted with an acquisition platform and software.
For example, the LeCroy SDA 11000 Serial Data Analyzer with the QualiPHY UWB package (Figure 2) can measure UWB signals in all six band groups, with software performing modulation analysis, such as quadrature phase shift keying and dual carrier modulation, constellation display, in-phase and quadrature versus time display, and magnitude phase versus tone display. Similarly, the SDA 11000 with the QualiPHY SATA package can handle Gen 2 SATA testing.
Protocol testing is becoming much more sophisticated as well. Ixia has a suite of offerings for IP test automation. From the basics of IPv6 through higher levels of triple play infrastructure, Ixia‚Äôs tools use deep packet inspection and real-world traffic emulation to provide the robust testing needed (see Figure 3). The IxLoad platform handles a variety of protocols over thousands of endpoints combining voice, video, and data traffic.
As interfaces in consumer electronics devices and networks have become more sophisticated, testing platforms have responded with better solutions. Trying to home brew testing products for these complex interfaces simply isn‚Äôt necessary with the variety of solutions available today.