VNA Concepts and Features
R&S
®
ZNL/ZNLE
210
User Manual 1178.5966.02 ─ 07
Figure 8-1: S11 trace in dB Mag format: sweep type Lin Freq (top) and Log Freq (bottom)
Conversion of Complex to Real Quantities
Among the measured quantities the R&S
ZNL/ZNLE supports, only "Stability" factors
and "Power Sensor" results are real. All other measured quantities are complex.
Power sensor measurements require option R&S
FPL1-K9. This option is not available
for the R&S
ZNLE.
The following table shows how "real" response values are calculated from complex
measurement values z = x + j y (where x, y, z are functions of the sweep variable). The
formulas also hold for real measurement values (y = 0).
Trace Format
Description
Formula
"dB Mag"
Magnitude of z in dB
dB Mag(z) = 20 * log|z| dB
"Phase"
Phase of z
φ (z) = arctan (y/x)
"SWR"
(Voltage) Standing Wave Ratio
SWR = (1 + |z|) / (1 – |z|)
"Lin Mag"
Magnitude of z, unconverted
|z| = sqrt ( x
2
+ y
2
)
"Real"
Real part of z
Re(z) = x
"Imag"
Imaginary part of z
Im(z) = y
"Delay"
Group delay, neg. derivative of the
phase response
– d φ (z) / dΩ (Ω = 2
π
* f)
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