C-SCOPE CS1220XD Instructions Manual page 7

Function Switch (3)
This rotary switch selects the Pre-programmed modes Meter Audio Disc and Meter Disc
or the Manual Control modes GD1 and GD2.
When set to either METER DISC or METER AUDIO DISC, the levels of Discrimination
or Rejection are identical (Discrimination can be defined as the ability to give a different
type of signal for ferrous junk or worthless objects than the signal given by a non-ferrous
object). Both these Discriminate Modes are set at such a level, so that depth penetration to
coins etc. is good, and discrimination against most iron and silver foil is achieved. A
precise level of discrimination is selected to give maximum rejection, without affecting
sensitivity to coins etc. Pull tabs, large silver foil, or large iron will not be rejected,
because the levels of discrimination required to reject these also reduce the depth
penetration to certain non-ferrous metals and thin section objects.
It is very unlikely that a valuable object will be rejected with the CS1220XD's AUDIO or
METER DISCRIMINATION modes.
Meter Audio Disc Mode
In this mode, the Meter (8) will display rejected targets by the needle moving to the left of
central. Positive targets, i.e. those likely to be worthwhile digging for, are indicated by no
needle movement or a deflection to the right of centre.
The Audio signal will also vary in pitch providing further analysis of the target. An
increase in pitch (high tone) is a good object and a decrease in pitch (low tone) is a bad
object.
In summary Meter Audio Disc is target analysis using both Meter and Audio signals.
Meter Disc Mode
In this mode the Meter (8) will display rejected targets by the needle moving left of centre
and good targets by not moving or moving to the right of centre.
The audio signal will be at a fixed pitch whatever the target composition, only the
loudness will vary depending on signal strength.
In summary Meter Disc is target analysis using the Meter for metal content and loudness
to indicate target size or depth.
The Manual Control Modes, GD1 and GD2
In the Manual Control Modes the detector utilises one of two circuits. One is for
optimisation against unwanted Ground signals and one is for Discriminating against
unwanted targets.
Ground G
The ground signals are due to the natural mineral deposits or contamination e.g. carbon or
slag left from industrial processes. The circuit to ignore the ground signals is preset during
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