Rohde & Schwarz 1145.1010.04/05/06, Руководство по эксплуатации

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Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.64 E-6
in the sweep range between any set of positive start and stop values. The sweep points must
be equidistant. No assumption is made about the measurement point at zero frequency (DC
value). The time domain result is complex with a generally undetermined phase depending on
the delay of the signal.
•
Low pass mode : The measurement results are continued towards f = 0 (DC value) and
mirrored at the frequency origin so that the effective sweep range (and thus the response
resolution) is more than doubled. Together with the DC value, the condition of equidistant
sweep points implies that the frequency grid must be harmonic. Due to the symmetry of the
trace in the frequency domain, the time domain result is harmonic.
The band pass and low pass modes are compared below.
Transform type Band pass Low pass
Advantages Easiest to use: works with any set of
equidistant sweep points
Higher response resolution (doubled)
Includes information about DC value
Real result
Impulse and step response
Restrictions No step response
Undetermined phase Needs harmonic grid
Use for... Scalar measurements where the
phase is not needed
DUTs that don't operate down to f = 0
(e.g. pass band or high pass filters)
Scalar measurements where the sign is of
interest
DUTs with known DC value
Remote control: CALCulate<Ch/Tr>:TRANsform:TIME[:TYPE]
Impulse and Step Response
In low pass mode, the analyzer can calculate two different types of responses:
•
The impulse response corresponds to the response of a DUT that is stimulated with a short
pulse.
•
The step response corresponds to the response of a DUT that is stimulated with a voltage
waveform that transitions from zero to unity.
The two alternative responses are mathematically equivalent; the step response can be obtained by
integrating the impulse response:
Integrate
impulse
response
Obtain
step
response
The step response is recommended for impedance measurements and for the analysis of
discontinuities (especially inductive and capacitive discontinuities). The impulse response has an
unambiguous magnitude and is therefore recommended for most other applications.
Remote control: CALCulate<Ch/Tr>:TRANsform:TIME:STIMulus