Zonge GDP-32 - Page 141

TIME DOMAIN INDUCED POLARIZATION (TDIP)
Section 9, Page 5 May 2002
Mode
The TDIP Survey Program has three different mode settings:
Synchronous - Synchronous operation assumes that the receiver and transmitter
have identical timing clocks and have been synchronized or phase-locked. (To use
this option, the receiver and transmitter must have the high-accuracy clock that is
standard with the GDP-32
II
.) This data acquisition method provides the best data
quality under varied conditions.
Non-ZERO Tx - This asynchronous mode is available for operators with a GDP-32
II
using a non-ZERO transmitter. This program first finds the frequency of the
transmitter and locks on to the signal. Assuming the transmitter has a stability of one
part in 10
-3
or better, during the data acquisition time this option gathers accurate
TDIP data under low to moderately noisy conditions.
Asynchronous - Used for asynchronous or non-phase-locked mode operation with
a ZERO built transmitter or a transmitter controlled with an XMT-series controller.
The program uses a cross-correlation routine to synchronize with the transmitted
waveform, then stacks and averages waveforms in a synchronous format. This option
gathers accurate TDIP under low to moderately noisy conditions.
Gain Mode
The default mode is "Noisy". This limits the gains to obtain a maximum voltage of 1.0 Volts,
leaving headroom for SP drift and random noise spikes. The other option is "Standard" which
adjusts the gains for a maximum voltage of 2.25 Volts.
Environment Type
The TDIP Survey Program allows for two Environment Types:
Quiet (default)
Noisy - To be used in noisy environments. Uses low-pass filters with the same
value as the RPIP program. The Noisy option strongly affects the first window on the
decay curve due to the extra filtering.