Velleman PCSU1000 DSO - Manual (Page 9)

Contents 8
© 2005 ... Velleman
Time parameters
Duty Cycle
The ratio (expressed as a percentage) of the average positive pulse width to the average period of the
signal. The time intervals are determined at middle reference level.
Duty Cycle = (Positive Pulse Width)/Period x 100%
Positive Width
Average positive pulse width in the waveform.
The time intervals are determined at middle reference level.
The middle reference is the middle point between the high and low levels.
Negative Width
Average negative pulse width in the waveform.
The time intervals are determined at middle reference level.
Rise Time
Time for a signal's rising edge to go from the low reference level to the high reference level.
The low reference level is 10% and high reference level is 90% of the pulse amplitude.
Fall Time
Time for a signal's falling edge to go from the high reference level to the low reference level.
The low reference level is 10% and high reference level is 90% of the pulse amplitude.
Period
The time interval between two consecutive crossings on the same slope of the signal at the middle
reference level.
Frequency
The inverse of the Period of the signal.
Phase
Phase angle in degrees between CH1 and CH2.
For phase measurement the frequency of CH1 must be equal to the frequency of CH2.
Phase measurement is time consuming process. In slow PCs this reduces the display update rate.