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Press the NEXT SECTION blue softkey until the display reads "Set up to measure fast
edge amplitude". Then follow these steps to calibrate edge amplitude:.
1. Connect the Calibrator Mainframe's CHAN 1 connector to the HP 3458A input,
using the N to BNC cable and the BNC(f) to Double Banana.
2. Set the HP 3458A to DCV, NPLC = .01, LEVEL 1, TRIG LEVEL, and the DELAY
to .0002 for measuring the upper part of the wave form (i.e. topline), and the
DELAY to .0007 for measuring the lower part of the wave form (i.e. baseline).
Manually lock the HP 3458A to the range that gives the most resolution for the
baseline measurements. Use this same range for the corresponding baseline
measurements at each step. Note that in the EDGE function, the topline is very near
0 V, and the baseline is a negative voltage.
3. For each calibration step, take samples for at least two seconds, using the HP 3458A
MATH functions to enter the average or mean value. See "Setup for Scope
Calibrator Edge and Wave Generator Measurements" for more details.
The "true amplitude" of the wave form is the difference between the topline and baseline
measurements, correcting for the load resistance error. To make this correction, multiply
the readings by (0.5 * (50 + Rload)/Rload), where Rload = actual feedthrough
termination resistance.
3-16. Leveled Sine Wave Amplitude Calibration
This procedure uses the following equipment:
HP 437A Power Meter or equivalent
HP 8481D Power Sensor
HP 8482A Power Sensor
N (female) to BNC (female) adapter
N to BNC cable supplied with the Scope Calibrator
Select the NEXT SECTION blue softkey until the display reads "Set up to measure
leveled sine amplitude". Then follow these steps to calibrate Leveled Sine Wave
amplitude.
1. Connect the N to BNC cable to the Calibrator Mainframe's CHAN 1 connector.
Connect the other end of the N to BNC cable to the 50
then to the 5790A INPUT 2 using the BNC(f) to Double Banana adapter. Refer to
Figure 3-3 for the proper equipment connections.
2. Set the 5790A to AUTORANGE, digital filter mode to FAST, restart fine, and Hi
Res on.
3. Press the GO ON blue softkey.
4. Press to activate operating mode on the Calibrator Mainframe.
5. Allow the 5790A rms reading to stabilize. Multiply the 5790A reading by (0.5 * (50
+ Rload) / Rload), where Rload = the actual feedthrough termination resistance, to
correct for the resistance error. Enter the corrected rms reading via the Calibrator
Mainframe front panel keypad, then press ENTER.
Calibration and Verification
Leveled Sine Wave Amplitude Calibration
feedthrough termination
3
3-13
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