Concepts and features
R&S
®
ZNA
115User Manual 1178.6462.02 ─ 29
Both "Imb Start Power" and "Imb Stop Power" must be in the range between
-150 dBm and 100 dBm. The analyzer generates a balanced signal with configura-
ble frequency and power, however, the amplitude of one signal component or the
relative phase of the two components is varied according to this range.
●
"Phase Imbalance"
This sweep mode is available in True differential mode only.
Both "Imb Start Phase" and "Imb Stop Phase" must be in the range between -180°
dBm and 180°. The analyzer generates a balanced signal with configurable fre-
quency and power, however, the relative phase of the two components is varied
according to this range.
The selected sweep range applies to all source and receive ports of the analyzer.
In arbitrary mode (with option R&S ZNA-K4), you can define port-specific frequencies
and powers; see Chapter 5.12.2.2, "Port Settings dialog", on page 668.
4.1.4.4 Wait time control
Equipped with several sources and receivers, and operating in various sweep and
measurement modes, the synchronization of a VNA's sub-modules is essential to
ensure reliable and reproducible results. To ensure proper synchronization and repro-
ducible measurements, with sources and receivers in settled states, the R&S ZNA FW
applies different algorithms to calculate the required wait times in a channel.
Although these wait time algorithms are designed for certain measurement tasks, they
are still general and try to balance the conflicting targets of measurement precision and
speed. Depending on the measurements to be performed, there can be some room for
optimization, especially if for your application speed is more important than accuracy,
or vice versa. The wait time control feature of the R&S ZNA allows you to shift the bal-
ance towards your primary target, and to observe the detrimental effects on the secon-
dary one.
Wait time control algorithms
The task of calculating "suitable" wait times has to consider many aspects and their
dependencies. The overall time the VNA requires to prepare for the next measurement
depends on:
●
The current and target HW settings (frequency, power, filters etc.)
●
The current and target HW usage (generators/synthesizers, step attenuators, inter-
nal switches etc.)
●
Channel and sweep state (certain channel/sweeep events require extra prepara-
tion time)
Because the wait times also depend on the accuracy that is required for a particular
measurement, the FW distinguishes between three wait time control algorithms:
1. Mono-frequent: Calculates wait times that are suitable for mono-frequent mea-
surements.
Basic concepts
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