This program is written using Microsoft C and the National GPIB Drivers. It shows how to get a crossing level either in the positive direction or negative direction using a Tektronix TDS oscilloscope.
User inputs are: Level the level is in Digitizing levels where the waveform crosses in the vertical direction. 0 center screen 25 levels/div.
The crossing direction: PCROSS or NCROSS, PCROSS is when the waveform goes through the crossing level in the positive direction or from bottom to top.
NCROSS is when the waveform goes through the crossing level in the negative direction or from top to bottom. The user also inputs the direction of the search, where searching from left to right is a positive search and searching from right to left is a negative search