Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 376 / 813

Channel Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.214 E-6
Purpose of a receiver power calibration
A receiver power calibration ensures that the power readings at a specified input port of the analyzer
agree with the source power level calibrated at an arbitrary reference plane. Typically, the reference
plane is at the input of the receiver so that the calibration eliminates frequency response errors in the
calibrated receiver.
A receiver power calibration generally improves the accuracy of power (wave quantity) measurements.
Calibration procedure and calibration sweep
The receiver power calibration is based on a wave with known power.
•
No external connection is needed for a receiver power calibration on the reference receiver
(wave quantity a
n
with Port n used as a source). Besides, the reference receiver is
automatically calibrated together with any source power calibration of an analyzer port.
•
Calibration of a received wave b
n
involves an external test setup. The received wave to
calibrate can be generated by the analyzer or an external generator.
The receiver power calibration involves a single calibration sweep. The calibration sweep is performed
with current channel settings but with a maximum IF bandwidth of 1 kHz. Smaller IF bandwidths are
maintained during the calibration sweep; larger bandwidths are restored after the sweep.
The analyzer measures the power at each sweep point, compares the result with the nominal power of
the source, and compiles a correction table.
An acoustic signal indicates the end of the calibration sweep. At the same time, a message next to the
calibrated source indicates the status of the receiver power calibration. After a change of the sweep
points or sweep range, the analyzer interpolates or extrapolates the calibration data.
The Receiver Power Cal dialog provides the following control elements:
•
Wave Quantity to Calibrate provides two pull-down lists to select one of the transmitted waves
a
n
or one of the received waves b
n
for the calibration. Each power calibration only applies to the
selected wave quantity in the active measurement.
•
Receiver Power Correction Off can be selected/deselected as soon as power calibration data
have been acquired for the active wave quantity. If the box is checked, the calibration data is
kept in memory but not applied to the wave quantity. The
Power Correction Off softkey disables
the power correction for all receivers and sources.
•
Used Source contains all analyzer ports or external generators which can which can be used as
a source for the calibrated wave quantity. The list contains all analyzer ports Port 1 to Port n .