258 Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
15 Measurements
 
• “Delay" on page 261
• “Phase" on page 262
• “X at Min Y" on page 264
• “X at Max Y" on page 264
Period
Period is the time period of the complete waveform cycle. The time is measured 
between the middle threshold points of two consecutive, like-polarity edges. A 
middle threshold crossing must also travel through the lower and upper threshold 
levels which eliminates runt pulses. The X cursors show what portion of the 
waveform is being measured. The Y cursor shows the middle threshold point.
Frequency
Frequency is defined as 1/Period. Period is defined as the time between the 
middle threshold crossings of two consecutive, like-polarity edges. A middle 
threshold crossing must also travel through the lower and upper threshold levels 
which eliminates runt pulses. The X cursors show what portion of the waveform is 
being measured. The Y cursor shows the middle threshold point.
See Also • “To isolate an event for frequency measurement" on page 258
To isolate an event for frequency measurement
The following figure shows how to use Zoom mode to isolate an event for a 
frequency measurement.
You may need to change the measurement window setting so that the 
measurement is made in the lower, Zoom window. See “Measurement 
Window" on page 272.
If the waveform is clipped, it may not be possible to make the measurement.