GW Instek GDM-398 - Manual (Page 36)

MEASUREMENT OPERATION
34
2. Set the rotary switch to Hz%; frequency measurement is set to (Hz) as default,
otherwise press the Hz% button (GDM-360/397/398) or the yellow button
(GDM-461) to select Hz measurement mode.
3. Connect the test leads to the DUT.
The measured value shows on the display.
4. If you need to measure the duty cycle, press the Hz % button (GDM-
360/397/398) or the yellow button (GDM-461) to select % measurement mode
Note
 Input Amplitude: (DC offset is zero)
 GDM-360/397/398: When 10Hz ~ 10MHz: 200mV ≤a ≤ 30Vrms
 GDM-461:When 10Hz ~ 10MHz: 300mV ≤a ≤ 30Vrms
When ≈10MHz ~ 40MHz: 400mV ≤ a ≤ 30Vrms
When ≥ 40MHz: unspecified
 For GDM-461: When measuring Audio frequency, if the input voltage is more
than 15volts the meter will simulate the sound at the same frequency.
 When frequency measurement has been completed, disconnect the connection
between the testing leads and the circuit under test, and remove the testing leads
away from the input terminals of the Meter.