Specifications

8-5 GATING Gating is a time filter that allows for removing unwanted time-domain
responses by gating the desired response. We can view the isolated
response in both time domain—and in the frequency domain—using
the FREQUENCY WITH TIME GATE selection (Figure 8-17).
There are four different gate shapes available: MINIMUM,
NOMINAL, WIDE, and MAXIMUM (Figure 8-18). The MS462XX
defaults to the NOMINAL gate. To specify a different shape simply
enter the Gate menu and select the desired gating shape. The
MINIMUM has the sharpest roll off and some frequency domain
ripple, while MAXIMUM has the least roll off and best residual ripple.
Figures 8-19 through 8-22, on the next page, show gating shapes.
The combinations of gate/window shapes will be restricted. For the
MINIMUM gate shape, the LOW and MIN SIDELOBE window shape
will not be allowed. For the NOMINAL gate shape, the MIN
SIDELOBE window will not be allowed. If the user has set the
window shape to MIN or LOW SIDELOBE and changes the-gate
shape to MINIMUM, the window will be reset to NOMINAL. If the
user has set the window to MIN SIDELOBE and changes the gate
shape to NOMINAL, the window will be reset to LOW SIDELOBE.
Gate shapes will be adjusted in a similar manner.
TIME GATING
DOMAIN
MS462XX OM 8-13
GATE
DISTANCE
GATE APPLIED
GATING
Figure 8-17. Gating
Figure 8-18. Gating Soft-Key Menus
LOWPASS TIME
DOMAIN SETUP
MARKER RANGE
WINDOW SHAPE
XXXXXXXXXXXX
GATE SETUP
D.C. TERM
XXXXXXX
XXXXXXXXXXX
RETURN
LOWPASS TIME
DOMAIN SETUP
START
XXX.XXX ps
STOP
XXX.XXX ps
CENTER
XXX.XXX ps
RESPONSE
IMPULSE/STEP
MORE
WINDOW/GATE
SHAPE
RECTANGULAR
NOMINAL
LOW SIDELOBE
MIN SIDELOBE
HELP ON/OFF
RETURN