Operator`s manual

Figure 4-10. AC coupled timing measurements with Threshold DAC.
In Figure 4-10, the DMM is set to 3.3 ACV range, while the input is a 10% duty-cycle wave with 5 V peak-to-
peak. Due to AC coupling, the input at the comparator is –0.5 V to + 4.5 V. The Median Value is +2.0 V,
which would be the optimal Threshold value.
Figure 4-11. Comparator and Threshold DAC Settings
4.12.2 Frequency and Period Measurements
Signametrics 36
Both V or ACI functions are selected. These check boxes are
used . Freq. measures from 1 Hz to 300 kHz. When activated, the
le.
nd.
ting t , a
he SM2042 and SM2044. See “Threshold DAC”, “AC Median Value”, and “Peak-to-Peak”
m surements for further details.
Freq. and Per check boxes are only visible when AC
to make frequency or period measurements
control panel alternately updates the amplitude reading followed by the frequency reading. The reading rate is
slower than indicated when frequency is activated. In the Windows control panel, period (Per) is also selectab
Once the frequency range is acquired, Frequency and Period have a maximum measurement time of about 1 seco
It could take up to five measurements before the correct frequency range is auto-selected. This process is automatic.
Once within range, the next frequency measurement is made at the last selected range.
Both Frequency and Period measurement performance can be improved by properly set he Threshold DAC
novel feature of t
ea