Operator`s manual

19 Signametrics
2.10 Time Measurements
2.10.1 Threshold DAC (SMU2064)
 The Threshold DAC is used for selecting a detection level, providing optimal frequency and time
measurements even at extreme duty cycle values.
Accuracy ± (% of setting + volts)
Selected VAC
range [1]
Threshold range (DC
level)
Threshold
DAC
resolution
Highest allowed input
Vp-p
Typical one year setting
uncertainty
240 mV -1.0 V to +1.0 V 0.5 mV 1.900 V 0.2% + 4 mV
2.4 V -10.0 V to +10.0 V 5.0 mV 19.00 V 0.2% + 40 mV
24 V -100.0 V to 100.0 V 50 mV 190.0 V 0.2% + 0.4 V
240 V -400 V to 400 V 500 V 850.0 V 0.2% + 4 V
[1] This table should be used in conjunction with the AC volts section above.
2.10.2 Frequency and Period Measurements
 Input Impedance 1 M with < 300 pF for voltage, 0.15 to 10 for current.
 Ranging Auto-Ranging (default) or Range-Lock
 Maximum acquisition time while in Auto-Ranging mode 7s
 Acquisition Time in Range Locked mode 35ms to 2s
Frequency One Year accuracy (% of
reading + Hz)
Resolution (Hz) Minimum amplitued (VRMS)
1Hz – 130Hz 0.025% + 0.0015Hz 1 mHz
130Hz – 640Hz 0.025% + 0.02Hz 6.5 mHz
640Hz – 2.5kHz 0.03% + 0.075Hz 25 mHz
2.5kHz – 40kHz 0.03% + 1.2Hz 0.4 Hz
30mV or 5% of range, whichever is
greater
40kHz – 200kHz 0.05% + 7Hz 2.5 Hz
200kHz – 300kHz 0.07% + 5Hz 1.5 Hz
25% of range
2.10.3 Duty Cycle Measurement
Frequency Range 2 Hz to 100 Hz 100 Hz to 1 kHz 1 kHz to 10 kHz 10 kHz to 100 kHz
Resolution 0.02% 0.2% 2% 20%
Typical Uncertainty is
±0.03% of reading ±
adder shown
0.03% 0.3% 3% 20%
Full scale reading 100.00 % 100.00 % 100.00 % 100.00 %
2.10.4 Pulse Width
± (% of reading + sec)
Polarity Frequency range Resolution Width range Typical
Uncertainty
Positive or negative pulse
widths
2 Hz to 100 kHz
1 s 2 s to 1 s 0.01 +/- 4 s
2.10.5 Totalizer (SMU2064)
 Selectable edge polarity: Positive or negative edge transition
 Maximum count: 10,000,000,000
 Allowed rate: 0.2 to 45,000 events per second
 Threshold: Set Threshold DAC
 Accuracy: ±2 counts