VNA concepts and features
R&S
®
ZNL/ZNLE
272
User Manual 1178.5966.02 ─ 19
9.5.6
Scalar power calibration
R&S
ZNL only
The purpose of a scalar power calibration is to ensure accurate source power levels
and power readings at a particular position (calibration plane) in the test setup. Scalar
power calibration is different from the system error correction described in
A power calibration is required for accurate measurement of wave quantities or ratios
(see section
on page 190). For best accuracy, choose a cal-
ibration method according to the table below.
Table 9-11: System error correction and power calibration for various measurements
Measurement
System error correction
Scalar power calibration
S-parameter meas. on linear
DUTs
Yes, necessary
Not necessary
Meas. of wave quantities or ratios
on linear or non-linear DUTs
Yes, recommended
a-wave: power (source) neces-
sary
b-wave: meas. receiver necessary
Power sweep, e.g. for compres-
sion point measurement
Yes, necessary
Power (source): necessary
Meas. receiver: not necessary
In general, a power calibration involves two stages:
1.
Source power calibration:
An external power meter is connected to the calibra-
tion plane. The analyzer uses the power meter readings to calibrate its reference
receiver. Subsequently, it modifies its source power so that the calibrated reference
receiver reading corresponds to the desired source power value (flatness calibra-
tion).
Tip:
It is also possible to perform the source (flatness) calibration using the power
meter (without previously calibrating the reference receiver).
Calibration
