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Figure 3 Agilent’s Infiniium 9000 series scopes offerbandwidths of 600 MHz to 4 GHz. Each model comesin a 9-in.-deep package and has a 15-in. LCD.their needs. The scopes come with a selectionof debugging, protocol-triggeringand -decoding, jitter-analysis, andcompliance applications. Agilent offersprotocol-triggering and -decoding supportfor 12 protocols, including I 2 C, SPI,RS-232/UART, CAN, LIN, FlexRay,JTAG (Joint Test Action Group), USB(Universal Serial Bus), PCIe (PeripheralComponent Interconnect Express),MIPI D-PHY (digital physical layer),SATA (serial advanced-technology attachment),and 8b/10b.According to Woodward, Agilent isthe only vendor to support both traditionalhardware triggering and software-basedtriggering, which the companycalls InfiniiScan. Hardware-basedtriggering enables a wide range of predefinedtrigger conditions from whichusers can select. The hardware triggeringembraces analog, digital, and protocoltriggers to catch even the rarestof events. “Software-based triggeringenables the user to graphically definea trigger,” Woodward says. “The scopethen compares each acquisition to thetrigger specification and displays onlythe acquisitions that match the triggerspecification.” You can also cascadehardware and software triggers to createmultistage triggers.Digital or logic triggering is helpfulin systems for which you wantto verify performance across manydata points but have few concernsabout signal integrity, according toChris Loberg, senior technical-marketingmanager atTektronix. “The digitaltrigger can speedup verification withouttying up time worryingabout analogsignalcharacteristicsthat may not be importantdue to alower clock speedor logic type,” hesays. Analog eventbasedtriggering iscritical, however,for performing signal-integritychecksor for drilling deeperinto signal performanceduringdebugging. Whenyou combine analogtriggering with ahigh waveform-displayrate, such as theone that Tektronix’sDPX (digital-phosphortechnology)provides, the debugging capability improvesdramatically, Loberg adds.Woodward echoes Driver’s emphasison the importance of flexible probingoptions. “Scopes need to connectto target systems,” he says, and customersmust choose the right probes and beable to later add probes. Agilent’s Infiniiumscopes work with a range of singleended,differential, high-voltage, andcurrent probes. “We’ve developed thisprobing arsenal over a numberof years by working withkey customers and helpingthem solve their probingchallenges,” he explains.“During just the last year,Agilent introduced morethan 27 probes.”Figure 2 Windowsbasedoscilloscopes,such as LeCroy’s 2-GHz WaveRunner (left), can accommodateserial-data packages that support ARINC 429, MIPI, I 2 C, SPI,UART, RS-232, CAN, LIN, FlexRay, and AudioBus interfaces.LeCroy’s new measurement-and-graphing package (right) displaysthe left- and right-channel data from a digital-audio sourcethat has undergone conversion into corresponding analog valuesand plotting over time to represent the converted analog-audiowaveform. The example is from a Pink Floyd audio track andrepresents about a half-second of audio.USABILITY IS KEYTektronix addresses the1- to 4-GHz scope marketwith scopes such as itsDPO7000 series (Figure 4)and its MSO (mixed-signaloscilloscope)4000 series.“One thing that commonlyhappens is users tend to focusin on one banner specor feature rather than thefull breadth of factors, includingvalue, performance,usability, probing solutions, and vendorexpertise,” says Loberg. Usability is a keyfactor. “When deciding to invest in thislevel of scope, the usability of the instrumentis critical. For example, many oftoday’s modern scopes in this range featureserial decoding that quickly speedsup an engineer’s ability to understandthe exact traffic being sent on commonserial buses,” he adds.Ting at Yokogawa agrees. “User interfaceis very important not only for engineers’productivity, but also for theirmental health. An intuitive interface,menu tree, and optimized keystrokesfor each operation all make for an improveduser experience.” He notes thatusability often depends on familiarity.Each vendor implements user-interfacemethods unique to its instruments.Yokogawa oscilloscopes, for example, allemploy a jog shuttle, which comprisesan inner dial with detents and an outerdial with a spring-loaded ring. “Userswho are familiar with our interfaceare reluctant to change to other vendors[and vice versa],” Ting says.Woodward at Agilent attributes theusability features of its Infiniium scopesto the company’s continual refinementof the instruments, which it bases oninput from a large installed base. In responseto Agilent’s queries about us-34 EDN | SEPTEMBER 9, 2010