Just over three months ago, LeCroy introduced its LabMaster 10 Zi as the world’s fastest real-real time oscilloscope, with 60-GHz bandwidth using digital bandwidth interleaving and four-channel operation at 36 GHz (see “Scope Sports 60-GHz Real-Time Bandwidth And Four Channels”). That instrument remains an impressive achievement, but it no longer can claim the speed title.
For the time being, that honor now goes to Agilent Technologies’ 90000 Q-Series (see a video here). These oscilloscopes boast a maximum two-channel bandwidth of 63 GHz (–3-dB point) and a four-channel bandwidth of 33 GHz (Fig. 1). The 90000 Q-Series includes 10 four-channel models ranging from 20 GHz to 63 GHz.
What does a bandwidth of 62.8 GHz mean in practical terms? For one thing, it enables capture of the third harmonic on 28-, 32-, and 40-Gbit/s digital signals. The scopes also can directly digitize M-band signals from 60 to 100 GHz. They perform analysis of IEEE 802.3ba 40/100/400-GbE and Optical Internetworking Forum CIE 3.0 signals as well.
Users can measure up to four differential channels in a single acquisition to examine crosstalk issues. The scopes will directly measure voltage swings larger than 1 V when you want to make high-bandwidth and general-purpose measurements with the same instrument. It also allows measurement of rise times as fast as 7 ps and data rates to 120 Gbits/s.
In terms of banner specs other than the bandwidth, the scopes offer sampling rates of either 80 or 160 Gsamples/s. Memory depths start at 20 Mpoints for DSOs and are as high as 2 Gpoints. The noise floor is an impressive 4.4 mV at 50 mV/division and at the full 63-GHz bandwidth. The specified jitter-measurement floor is 75 fs.
Spurred primarily by the need for higher bandwidths to characterize and test next-generation optical communications systems, Agilent’s design team has leveraged technology developed for its earlier 90000 X-Series scopes. The Q-Series instruments use an indium-phosphide (InP) chipset instead of silicon germanium, preferring InP’s breakdown voltage versus frequency curve.
“We think InP still has a lot of legs in terms of future bandwidth jumps,” says Brig Asay, Agilent’s product manager for its high-performance scopes (see “Software Compensates For Probes, Cables,”). InP pre-amplifiers also offer flat frequency response and can handle high speeds and voltages.
Agilent’s new RealEdge technology comprises a combination of new architectures, next-generation microcircuits, and the aforementioned InP technology. RealEdge is what lies behind the instruments’ industry-low noise and jitter-measurement floor.
Within the scope’s chassis are either two acquisition boards, each with two 16-GHz channels and one 33-GHz channel, or four acquisition boards, each of which carries one 33-GHz channel. The four-channel models also offer a redesigned backplane board and a large, 15.1-in. display.
This kind of performance would not be possible without some key ancillary technologies. Most important is Agilent’s InfiniiMax III 30-GHz probing system, which includes probe amplifiers, heads, and adapters. The company’s InfiniiView analysis software enables scope users to analyze data using a separate PC or laptop instead of co-opting scope resources. And, Agilent’s N2807A PrecisionProbe Advanced software automatically characterizes probes and cabling to correct for impedance problems, extending the probing system out to the scope’s full 63-GHz bandwidth.
The 90000 Q-Series scopes do come with a hefty price tag. The lowest-end model, the DSOX92004Q, with two- and four-channel bandwidths of 20 GHz, goes for $191,000. The top-of-the-line DSAX96204Q, with full 63-GHz two-channel bandwidth, commands $436,000. But if you have a pressing need to digitize to 63 GHz, your alternatives are non-existent. Scopes begin shipping in July.