NF FRA51602, Instruction Manual

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5.8 Automatic high density sweep
5
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30
FRA 51602
[VARIATION] : This is the parameter change threshold. If the amount of change relative to the
measurement at the previous frequency exceeds the value set here, it is judged
to be a sudden change and the automatic high density sweep is performed.
The parameter setting ranges and other such information is described in " 3.5.3 Sweep dialog ".
■ Example of automatic high density sweep setting
Typical examples of measurements for which the automatic high density sweep function is convenient are
measurements of the resonance characteristics of piezoelectric resonators and crystal resonators. In such
measurements, the phase θ changes suddenly near the resonance frequency. Accordingly, automatic high
density measurement only in the vicinity of the resonance frequency is possible if the monitoring
parameter [TYPE] is set to phase
θ
. Because phase is being monitored, the monitoring channel can be set
to either CH1 or CH2 and the operation is the same.
The change threshold value [VARIATION] can be initially set to about 10° and adjusted as necessary.
Setting this to a small value produces high density results, but the measurement time is long.
■ Monitoring parameters and reference channel
When the monitoring parameter [TYPE] is dBR or
θ
, the operation is the same whether the reference
channel is set to CH1 or CH2, because the quantity is determined by the measurement data between the
two channels.
When the monitoring parameter [TYPE] is R , a , or b , the measurement data (amplitude value, Vrms) of
the channel that is set as the reference channel is monitored. Even if the analysis mode setting (
【
Graph
】
–
[ANALYSIS MODE]
) is CH1/CH2 or CH2/CH1, the amplitude (Vrms) is monitored rather than the
gain (ratio).
■ Cautions concerning automatic high density sweep measurements
Setting
[VARIATION]
to a smaller value than is necessary will increase the number of frequency points.
If the maximum number of measurement points for this instrument (20,001) is exceeded, the error
message "-3072" is displayed and the sweep measurement is ended at that time. Please take note of this,
because the measurement ends without reaching either the upper measurement frequency limit or the
lower measurement frequency limit. For more information on the error message, refer to "
7.1 Error
messages
".