6-2
IM 253710-01E
Explanation
The observation time represents the time span of one screen. How the observation time
is determined depends on the measurement mode.
Observation time
Sampling rate
During the normal measurement mode
The selectable range is from 10
µ
s to 1 ks* (in 1-2-4 steps).
The sampling rate changes depending on the observation time. The sampling rate is
used to acquire the data to the acquisition memory. For details regarding the
observation time, sampling rate, and record length, see Appendix 1.
*
1 ks denotes 1000 s (16 minutes 40 seconds).
During the harmonic measurement mode
The observation time for the harmonic measurement mode is automatically
determined from the sampling rate that is determined from the fundamental frequency
of the PLL source (see section 6.4) and the record length (see section 1.3). The
observation time is not displayed. The observation times when the record length is
not divided (see section 6.4) are shown below.
• When the record length is 100 k-words : Approx. 0.5 to 1.6 s
• When the record length is 1 M-word : Approx. 4.9 to 16.3 s
• When the record length is 4 M-word : Approx. 19.5 to 65.1 s
For details regarding the observation time, sampling rate, and record length, see
Appendix 1.
Note
•
During the normal measurement mode, the observation time can be changed even when the
data acquisition is stopped. The new observation time takes effect when the data acquisition
is started.
Observation time that has been changed
Observation time of the displayed data
•
When the time base (see section 6.3) is set to external clock, the record length of data is
acquired by sampling at the rate of the external clock. In this case, the observation time is
not displayed.
•
For the harmonic measurement mode, the sampling rate depends on an external signal
referred to as the PLL source (signal under measurement or external clock signal) and
therefore, the observation time cannot be set uniformly as in the normal measurement mode.
In the harmonic measurement mode, the time it takes to store the record length of sampled
data in the acquisition memory is the time displayed on one screen.
6.1 Setting the Observation Time