Manual No. OM5000
Jan X/04 Ver 1.40
50
Also, refer to Section 6.4.3.4 and Figure 26 regarding the proper selection of the first half-
cycled T-Gate sync on the IF echo.
After setting the START/STOP switches, return the VIDEO to the proper polarity, the GAIN
control, if desired, to AGC and the SYNC SWEEP control to IF.
6.4.4 Blocking Actual IF Echo
- Sometimes, during delay line or immersion transducer
gaging, it may be desirable to select either the first back surface echo or a multiple and treat it
as an "artificial IF echo". This is accomplished by setting the IP-Gate beyond the true IF echo
and any subsequent echos until the sweep syncs on the desired echo. To utilize this special
technique requires that the artificial IF echo possesses an adequate amplitude to create a
reliable sync.
6.4.5 HI RES/NORM Switch
- The NovaScope allows the selection of either normal or
exceptionally high resolving power, via the left sidepanel HI RES/NORM switch for only those
interface gating applications (using a delay line or immersion transducer) where
plastic
thickness is being gaged between the interface echo and the first back surface echo.
This
switch should be set in the NORM (normal) position for all "standard" type transducers.
It can optionally be set to the HI RES (high resolution) position only for immersion and delay
line transducers that are exceptionally high in frequency and exceptionally well damped - for
thickness gaging very thin
plastic
materials by means of the interface-to-first back surface
echo approach. A modification is available to adapt this ultra-high resolution switching ability
to metals. Contact NDT Systems, Inc. regarding such applications and transducers.