T.O. 33B-1-1
5-77
Figure 5-76. Impedance Plane Display of a Pitch/Catch Impulse Method.
5.4.6.2.1
The pitch/catch impulse probe is directionally sensitive such that both active tips must be over the same condition of
bond for unambiguous signal interpretation. For example, Figure 5-77 shows the proper way to align the active tips for
precise mapping of unbonds.
Figure 5-77. Pitch/Catch Probe Positions for Mapping Unbonds.
5.4.6.2.2
Some pitch/catch instruments permit the operator to select the frequency, while in others the frequency is fixed.
Typically, selectable frequencies range from 2.5 to 70 kHz; the frequency providing the largest received signal, due to
