Concepts and Features
R&S
®
ZNC
94
User Manual 1173.9557.02 ─ 13
Preconditions for Auto Length, effect on measured quantities and exceptions
"Auto Length" is enabled if the measured quantity contains the necessary phase infor-
mation as a function of frequency, and if the interpretation of the results is unambiguous:
●
A frequency sweep must be active.
●
The measured quantity must be an S-parameter, ratio, wave quantity, a converted
impedance or a converted admittance.
The effect of "Auto Length" on S-parameters, wave quantities and ratios is to eliminate
a linear phase response as described above. The magnitude of the measured quantity
is not affected. Converted admittances or impedances are calculated from the corre-
sponding "Auto Length" corrected S-parameters. Y-parameters, Z-parameters and sta-
bility factors are not derived from a single S-parameter, therefore "Auto Length" is disa-
bled.
Auto Length for logical ports
The "Auto Length" function can be used for balanced port configurations as well. If the
active test port is a logical port, then the same length offset must be assigned to both
physical ports that are combined to form the logical port. If different length offsets have
been assigned to the physical ports before, they are both corrected by the same amount.
3.6.1.4
Auto Length and Loss
The "Auto Length and Loss" function ("CHANNEL > OFFSET EMBED > One Way Loss
> Auto Length and Loss") determines all offset parameters such that the residual group
delay of the active trace (defined as the negative derivative of the phase response) is
minimized and the measured loss is minimized as far as possible across the entire sweep
range.
"Auto Length and Loss" involves a two-step procedure:
●
An "Auto Length" correction modifies the phase of the measured quantity, minimizing
the residual group delay. The magnitude of the measured quantity is not affected.
●
The "Auto Loss" correction modifies the magnitude of the measured quantity, leaving
the (auto length-corrected) phase unchanged.
Preconditions for Auto Length and Loss, effect on measured quantities and excep-
tions
"Auto Length and Loss" is enabled if the measured quantity contains the necessary phase
information as a function of the frequency, and if the interpretation of the results is unam-
biguous:
●
A frequency sweep must be active.
●
The measured quantity must be an S-parameter, ratio, wave quantity, a converted
impedance or a converted admittance.
The effect of "Auto Length and Loss" on S-parameters, wave quantities and ratios is to
eliminate a linear phase response and account for a loss as described above. Converted
admittances or impedances are calculated from the corresponding "Auto Length and
Loss" corrected S-parameters. Y-parameters, Z-parameters and stability factors are not
derived from a single S-parameter, therefore "Auto Length and Loss" is disabled.
Offset Parameters and Embedding
