General

Channels : 8
Frequency Range : 0.001Hz to 8kHz
Filters : Anti-alias, powerline notch and telluric.
Size : 41 x 20 x 33 cm (41 x 20 x 45 cm for GDP-16)
Weight : 16 kg (20 kg for GDP-16)
Temperature Range : -40 to +60 degrees celsius
Time Base : Oven-controlled crystal oscillator.
Automatic SP buckout, gain setting and calibration.

Analog

Input : True differential for common-mode rejection.
Input Impedance : 10 Mohms at DC
Minimum detectable signal : 0.03 microvolt
Maximum input voltage : +/- 32 volt
Phase Accuracy : +/- 0.1 milliradian

Filter Section

Four-pole Bessel anti-alias filter.
Quadruple-notch, specified by user (e.g. 50/150/250/450 Hz, 50/150/60/180 Hz, 60/180/300/450 Hz, etc.)
Digital telluric filter.

Analog to Digital Converter

Resolution : 16 bits +/- 1/2 LSB
Conversion time : 17 microseconds
Continuous self calibration.
One A/D per channel.

Digital

Microprocessor : 386SX with math coprocessor. (80C186 with math coprocessor for GDP-16)
Memory : 4 MB ROM.
Two RS-232 serial and one parallel port.