Duty Cycle From Switch Node Voltage - Tektronix Keithley DMM7510 User Manual

Model DMM7510 7½ Digit Multimeter User's Manual
Send the following commands:
-- Reset the instrument to default settings.
reset()
-- Create a local variable to store the number of samples.
numofsamples = 100
-- Set the measure function to digitize voltage to capture the ripple waveform.
dmm.digitize.func = dmm.FUNC_DIGITIZE_VOLTAGE
-- Voltage range must be fixed when using digitize voltage.
dmm.digitize.range = 10
-- Set sample rate to 1 megasample per second to sample a
-- 50 kHz voltage ripple.
dmm.digitize.samplerate = 1e6
-- Set aperture to automatic to get the highest accuracy measurement
-- for the configured sampling rate.
dmm.digitize.aperture = dmm.APERTURE_AUTO
-- Set sample count to the number of samples to capture about 5 ripples.
dmm.digitize.count = numofsamples
-- Set the input impedance to automatic so it selects 10 G for the 10 V range.
dmm.digitize.inputimpedance = dmm.IMPEDANCE_AUTO
-- Set the buffer to align with the number of samples (optional).
defbuffer1.capacity = numofsamples
-- Clear buffer.
defbuffer1.clear()
-- Make sure your signal is connected to the DMM and digitize.
dmm.digitize.read()
-- Print the digitized readings.
if defbuffer1.n > 0 then
print("Ripple Voltage:")
print("Total Count:", defbuffer1.n)
printbuffer(1, defbuffer1.n, defbuffer1)
print("Timestamps:")
printbuffer(1, defbuffer1.n, defbuffer1.relativetimestamps)
else
print("No data collected")
end
print("Test Ended")

Duty cycle from switch node voltage

The switching duty cycle determines the voltage at the output compared to the input voltage, as
shown in the following equation:
DMM7510-900-01 Rev. C / September 2019
Section 10: Capturing and analyzing waveforms
10-7