NF FRA5087, Instruction Manual

Page: 80 / 194

4.2 Delaying measurement start
FRA5087
4-6
4.2 Delaying measurement start
When the oscillator frequency changes in the frequency sweep mode, the measurement data may,
in general, have errors due to transient response if the SUT (system under test) involves any
response time delay components. The measurement start time is set with some delay time period
for the FRA5087 frequency response characteristics measurement, so that the transient error can
be suppressed at the minimum level. You can set the delay time period at an arbitrary value
according to the time constant of the SUT.
Among others, note that sufficient period of time delay needs to be secured for measuring
accurately the SUTs that involve high order elements (e.g., filters with steep frequency
characteristics, high Q resonance circuits with crystal oscillators, etc.), since they have a long
period of time delay.
Use the menu [Measure][BASIC FUNCTION][DELAY TIME] to set the period of time delay.
The period of time delay can be set with respect to either the number of cycles of analysis
frequency (unit: cycle) or the time period (unit: second).
OSC frequency = f1 f2
Measurement time range
for the time delay
= 0.
Measurement time
range for the proper
amount of time delay.
time
OSC output
waveform
SUT response
waveform
Fig. 4-4 Response waveform requiring measurement start time delay