TEST & MEASUREMENT FEATURE
quickly between different DC supplies without having to continually readjust the offset compensation voltage.
The RT-ZPR20 power rail probe with integrated ProbeMeter outputs the high-resolution signal details to the RTE and RTO, including ripple, noise, transients and the power distribution network’s exact DC voltage
The spectrum analysis function in R&S oscilloscopes is a powerful tool for identifying unwanted coupled signals in DC power distribution networks. In the example, a coupled 2.4GHz WLAN signal is clearly visible
Solder-in pigtail coaxial cable for high bandwidth contacting
2GHZ BANDWIDTH Finding coupled signals and harmonics on the power rail has been another traditional challenge. With close proximity to clock signals and other types of coupling, power distribution networks are often subjected to high-frequency crosstalk that requires large bandwidths to measure. This lies outside the capabilities of lower-cost 38MHz passive probes with an attenuation factor of 1:1 often used for power integrity measurements. These probes are suitable only for measuring low- frequency ripple signals and would miss higher frequency transients. The RT-ZPR20 has a specified bandwidth of 2GHz and a typical 3dB point near 2.4GHz, which is why, for example, a coupled 2.4GHz WLAN signal will be visible. Power integrity measurements often include troubleshooting at slow timebases and fast oscilloscope sample rates. An oscilloscope must have deep memory to be able to measure for the long periods of time required in this situation. The hardware-accelerated FFT measurements in the R&S RTO and the R&S RTE provide users with a sufficiently fast spectral display to make their work easier.
HIGH INPUT IMPEDANCE The impact of probe loading on DC rails must be minimised to prevent DC values from changing due to probe loading. Power rails typically have impedances around 1mΩ. Connecting to a power rail via the 50Ω path on the oscilloscope, for example, will change the DC value. The R&S RT-ZPR20 probe’s DC input impedance measures 50kΩ to minimise its impact.
SUMMARY Today’s power integrity measurements with decreased rail voltages and smaller tolerances are a challenge to traditional oscilloscopes and probes. But they are no problem for the RT-ZPR20 power rail probe, which was designed specifically for these types of measurements. It is not only low noise with its 1:1 attenuation factor. With its ±60V offset range, 2GHz bandwidth, 50kΩ DC input impedance and integrated DC voltmeter, it offers everything users need to measure today’s DC power distribution networks. The probe can be used with R&S RTE (200MHz to 2GHz) and R&S RTO (600MHz to 6GHz) oscilloscopes.
Rohde & Schwarz
www.rohde-schwarz.com
INSTRUMENTATION | APRIL 2018
33
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
