Atec Agilent-8563E - Manual (Page 70)

ESG Family Signal Generators Performance Tests
10. Power Level Accuracy
Calibration Guide 4-21
10. Power Level Accuracy
A power meter is used to verify performance over the +13 to –15 dBm range. The absolute
power level measured at –10 dBm is used as a reference for all lower level measurements.
For power levels below
−
15 dBm, a vector signal analyzer is used to make relative power
measurements. A low noise amplifier (LNA) and step attenuator are connected in series to
control the absolute power level input to the signal analyzer. For power level settings
≥
–60 dBm, the step attenuator is set to approximately cancel the gain of the LNA. Below
–60 dBm, the step attenuator is set to 0 dB, which keeps the signal level well above the
signal analyzer’s noise floor.
Relative measurements are accomplished by setting the DUT amplitude. For example:
Set the DUT to a specific frequency, and an amplitude of –10 dBm. For the purpose of this
example, assume the power meter measures –10.1 dBm at these settings. The signal
analyzer does a peak search, sets the reference level, and sets the marker to delta mode
(0 dB). The DUT amplitude then changes to –20 dBm, and the signal analyzer makes a
relative power measurement (assume it to be –10.15 dB). The absolute power measured is
–10.1 dBm + (–10.15 dB), or –20.25 dBm.
To determine power level accuracy below –60 dBm, the signal analyzer makes the 0 dB
marker delta measurement with the amplitude set to –60 dBm, and all lower level
measurements are made relative to this reference. The previously measured error for the
–60 dBm setting is then accounted for in the measurement.
For frequencies above 2 GHz, an HP/Agilent 8563E signal analyzer is used to downconvert
the frequency to 321.4 MHz.
Recommended Equipment
• HP/Agilent 438A Power Meter
• HP/Agilent 8482A Power Sensor
• HP/Agilent 89441A Vector Signal Analyzer
• HP/Agilent 8563E Option 001 Signal Analyzer
• HP/Agilent 8491A/B Option 006 Attenuator (6 dB)
• HP/Agilent 8495G Programmable Step Attenuator (0 to 70 dB)
• HP/Agilent 11713A Step Attenuator Driver
See page 1-4 for Details on the following:
• Low Frequency Noise Amplifier (LNA)
• High Frequency Low Noise Amplifier (LNA)