Boonton 4530 Peak Power Meter Service Manual - Manual (Page 20)

BOONTON ELECTRONICS a WIRELESS TELECOM GROUP COMPANY
20
OR
Send “CAL1:INT:ZERO” to the Meas4530, and wait for the zeroing process to complete.
u. Send “$CAL:DAC [DtoA1]; $CAL:ATTEN [attenuator_step]” to the UUT, where the first
[attenuator_step] is 70. This sets the calibrator’s oscillator to the full scale power level (approximately
+20dBm) with the step attenuator set for 70dB attenuation, for an output of –50dBm.
v. Set the 2520’s RF output to the current step’s calibrator output level (-50dBm for the first step), and
turn “ON”
w. After waiting for the reading to settle, [Set Ref].
x. [Select UUT] and record the full scale error for the 70dB attenuator step (–50dBm output power).
The Attenuator Step Correction Coefficient is the inverse of this ratio, or the value in dBr negated.
y. Send “$CAL:COEF:[attenuator_step] [correction_factor]” to the UUT where [attenuator_step] is the
current attenuation setting from step “u” (70 to 0 in 10dB steps), and [correction_factor] is (-1.0 *
Reading_in_dBr). This stores the correction coefficient for the current attenuator step. Record this
correction factor below.
z. Repeat steps (u) through (y), and fill in the following chart for each attenuator step:
Atten Step Output Lev Corr Factor
70 dB -50 dBm________ dB (performed first time through the preceding steps)
60 dB -40 dBm________ dB
50 dB -30 dBm________ dB
40 dB -20 dBm________ dB
30 dB -10 dBm________ dB
20 dB 0 dBm________ dB (should be 0.000 +/- 0.010)
10 dB 10 dBm________ dB
0 dB 20 dBm________ dB
Note: All correction factors should be less than 1dB.
aa. Set the 2520’s RF output to –60dBm & “OFF”, then [select 2520].
bb. Send “$CAL:SAVE” to the UUT. This saves the new D-to-A and attenuator coefficients to the UUT’s
calbration memory. If this step is omitted, the calibration will be lost when the instrument is restarted.
7. Calibration Verification
This verification procedure should always be performed immediately after completion of calibrator
calibration, and it can also be performed independently. The test setup and terminology is identical to that
described above in 50MHz Calibrator Calibration.
a. If not already hooked up, connect the instruments as shown above and cycle the AC power on the
UUT.
b. Verify bus communications, and allow all equipment to warm up for at least 10 minutes. All calibrator
outputs should be off.
c. Wait at least one minute to allow the power sensor to cool from recent service at or above 0dBm.
d. Set the 2520’s RF output to -60dBm & “OFF”, then [select 2520].