60
Chapter 4 Calibration Procedures
Performance Verification Tests
4
Special Note:
Amplitude and Flatness Verification Procedures
Measurements made during the AC Amplitude (high-impedance)
Verification procedure (see page 63) are used as reference measurements
in the flatness verification procedures (beginning on page 64). Additional
reference measurements and calculated references are used in the
flatness verification procedures. Photo-copy and use the table on page 61
to record these reference measurements and perform the calculations.
The flatness verification procedures use both a DMM and a Power Meter
to make the measurements. To correct the difference between the DMM
and Power Meter measurements, the Power Meter reference
measurement level is adjusted to set the 0.00 dB level to the DMM
measurement made at 1 kHz. The flatness error of the DMM at 100 KHz
is used to set the required 0.00 dB reference.
The instrument internally corrects the difference between the high-Z
input of the DMM and the 50 Ω input of the Power Meter when setting
the output level.
The reference measurements must also be converted from Vrms (made
by the DMM) to dBm (made by the Power Meter).
The equation used for the conversion from Vrms (High-Z) to dBm
(at 50 Ω) is as follows:
Power (dBm) = 10 log(5.0 * V
rms
2
)
Flatness measurements for the –10 db, –20d B, and –30 dB attenuator
ranges are verified as a part of the 0 dB verification procedure. No
separate verification procedure is given for these ranges.
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