N2807A PrecisionProbe Advanced Kit

PrecisionProbe solves measurement challenges by allowing you to:

• Measure input impedance and response of any probe and the loss of any cable
• Quickly correct for probe and cable loss (without extra instruments such as VNA or TDR)
• Correct probing issues such as phase non-linearity, magnitude non-flatness, and see the effect of probe loading
• Quickly gain insight into the impedance/capacitance that defines your connection The Keysight Technologies, Inc. PrecisionProbe Advanced Kit (N2807A) includes award winning PrecisionProbe software as well as external hardware and accessories that allow you to characterize and correct your measurement system quickly and accurately to 63 GHz.

Background – PrecisionProbe

Probes and cables have inherent loss and variation. The loss at times can be substantial, or merely different enough from the nominal to cause variation in measurements. To compensate for the inherent loss, oscilloscope vendors use probe correction via DSP. The vendor uses a “golden” model and base, all compensation/correction on the single model. While this strategy solves some of the loss and variability, it also still means that if a probe’s characteristics have changed/drifted or were not close to the model to begin with, the compensation is no longer correct for the probe. There are also myriad probe heads to attach to probe amplifiers for maximum accuracy when every combination must be measured. The end result is that you can get unwanted inaccuracies or probe to probe variability.

The software quickly (less than five minutes in most cases) and accurately characterizes the desired element in the system without adding more equipment.

• Characterizes probe input impedance
• Properly Creates Custom Probe Transfer Function = VOut / VIn or VOut/VInc = VOut/VSrc
• Removes unwanted cable loss

Now every probe and cable in the system can have the exact same response probe to probe or cable to cable, without the inaccuraies that using one model can produce. Custom probes can now be properly characterized and unwanted responses can be removed. Not only does PrecisionProbe characterize the cables, it allows for immediate use on the same instrument. When combining PrecisionProbe with the 90000 Q-Series, 90000 X-Series, and 90000A Series oscilloscopes, one can characterize their measuring system and be using it within five minutes without adding more complicated, expensive equipment. PrecisionProbe saves time and money while increasing accuracy. When combining InfiniiMax probes with switches between the amplifier and the probe head, PrecisionProbe allows for full correction and automation of each probe’s path. Full automation is then available to allow for quick swapping of the inputs.

Vout/Vin Correction

Vout/Vin characterizes the output of the probe as a function of the input at the probe tips. Defining the response this way allows you to evaluate the probe’s accuracy in reproducing the actual signal present in your system with the probe attached. This correction is known as Vout/Vin, which is what you’d see with a real band limited probe that has finite input impedance. PrecisionProbe corrects the “Vout/Vin” response to be flat with frequency and phase to your defined bandwidth limit. It does not correct the loading effects of the probe. It should be noted that Keysight’s probe frequency response corrections are typically defined using Vout/Vin.

Vout/Vsource Correction

The second way to correct probes is an estimate known as Vout/Vsource, this method corrects the probe as “what would be there if the probe were not present.” There are oscilloscope and probe manufacturers that design their probes and DSP correction software to display what the waveform “would have been” in the absence of the probe. One drawback of defining the probe’s response in this manner is that if the probe’s loading causes your circuit to lose some timing or amplitude margin, you probably want to know that when you make a measurement. Vout/Vsource compensation will hide these effects from you. PrecisionProbe also gives you the freedom to choose this method of correction, which can be effective if probing at the transmitter.

S21 Insertion Loss Correction

PrecisionCable can be used to remove insertion loss caused by cables or fixtures. Previously the only way to do this analysis was to characterize the cable using simulation, TDR, or a VNA. All of these methods can be accurate and can yield the desired results. You would then take the newly created s-parameter file to the oscilloscope and use the de-embedding software to remove the insertion loss of the fixture or cable. While this method works, it requires extra equipment and effort. PrecisionCable allows for this characterization to be done inside of the same oscilloscope that the measurements will be taken. Characterizing the cables and fixtures takes less than five minutes in many cases which saves significant time

Using PrecisionProbe provides the highest level of accuracy without requiring additional equipment. PrecisionProbe will help with accuracy in the following ways:

• Characterize the impedance of your probe
• Remove probe to probe variation
• Remove insertion loss caused by cables
• Correct custom probes
• Correct for browser variability caused by span and length variation
• Correct for solutions such as switch matrices

The N2807A PrecisionProbe Advanced Kit provides the same award winning software and features as the original PrecisionProbe (N2809A). While the original PrecisionProbe was limited to a maximum of 33 GHz characterization bandwidth, PrecisionProbe Advanced extends this functionality out to 63 GHz by including Keysight’s N2806A Calibration Pulse Generator.