User`s guide

Characteristics and Specifications 5
Electrical Specifications
U1273A/U1273AX User’s Guide 147
Frequency specifications
Duty cycle and pulse width specifications
Table 5-11 Frequency specifications
Range Resolution Accuracy Minimum input frequency
99.999 Hz 0.001 Hz 0.02% + 5
0.5 Hz
999.99 Hz 0.01 Hz 0.005% + 5
9.9999 kHz 0.0001 kHz 0.005% + 5
99.999 kHz 0.001 kHz 0.005% + 5
999.99 kHz 0.01 kHz 0.005% + 5
>1 MHz 0.1 kHz 0.005% + 5 @ <1 MHz
Notes for frequency specifications:
1 Overload protection: 1000 V; input signal is <20,000,000 V × Hz (product of voltage and frequency).
2 The frequency measurement is susceptible to error when measuring low-voltage and low-frequency signals. Shielding
inputs from external noise pickup is critical for minimizing measurement errors. Turning on the low-pass filter may help
you to filter out the noise and achieve a stable reading.
Table 5-12 Duty cycle and pulse width specifications
Function Mode Range Resolution Accuracy at full scale
Duty cycle
DC coupling 99.99% - 0.3% per kHz + 0.3%
AC coupling 99.99% - 0.3% per kHz + 0.3%
Notes for duty cycle specifications:
1 The accuracy for duty cycle and pulse width measurements is based on a 3 V square wave input to the DC 3 V range. For
AC couplings, the duty cycle range can be measured within the range of 10% to 90% for signal frequencies >20 Hz.
2 The range of the duty cycle is determined by the frequency of the signal:
{10 μs × frequency × 100%} to {[1 – (10 μs × frequency)] × 100%}