R&S 1332.4500K22, User Manual

Page: 247 / 1709

Concepts and features
R&S
®
ZNA
247 User Manual 1178.6462.02 ─ 20
Compared to conventional measurement methods, the mixer delay measurement
offers several additional advantages:
●
A network analyzer with standard functionality is sufficient.
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Easy calibration using a calibration mixer.
●
PUOSM calibration (for high gain DUTs)
●
See also "Two-tone generation and combination" on page 238.
●
Option R&S ZNA-K9 requires Direct generator/receiver access and the Frequency
conversion measurements option R&S ZNA-K4.
A 4-port R&S ZNA or a 2-port R&S ZNA with Internal 2nd source and 2nd LO genera-
tor for 2-port R&S ZNA is recommended, because of the second internal source. A
dedicated cable set for this measurement is provided with accessory R&S ZNAxx-Z9.
Group Delay Calculation w/o LO Access
The group delay τ
g
of a circuit is defined as the negative derivative of its phase
response. Hence, for two tones with phases Φ1 and Φ2 and a frequency difference
("aperture") Δf:
ΔΦ in and ΔΦ out are the phase differences of the two tones at the input and output of the
DUT, respectively.
The phase difference of the source signal ΔΦ in and the aperture Δf are known quanti-
ties. ΔΦ out depends on the DUT and can be measured. As a phase difference, ΔΦ out is
stable against variations of the LO frequency, because those will affect both signals in
the same way. This means that the mixer delay measurement does not require any
synchronization between the analyzer and the LO signal, even if the LO shows a
noticeable frequency drift.
4.7.4 Phase coherent source control
R&S ZNA-K6
With option R&S ZNA-K6, a R&S ZNA with two or more sources can generate signals
with defined phase. Typical application examples are measurements on balanced
DUTs or the supply of antenna arrays which are designed for a well-defined radiation
pattern.
●
For a two-port R&S ZNA, hardware option R&S ZNA-B52 is required. See Chap-
ter 4.7.22, "Internal 2nd source and 2nd LO generator for 2-port R&S ZNA" ,
on page 274.
●
With option R&S ZNA-K4, phase coherent signals can be generated at arbitrary
amplitudes and frequencies.
Optional extensions and accessories