SFERIC-EM is used to record naturally occurring transient electromagnetic energy for estimation of the impedance tensor and/or magnetic field tipper over the bandwidth 8 Hz to 32 kHz. Large transient amplitude coupled with time localized recording ensures the highest possible SNR in the raw data. Essentially unbiased estimation of the impedance tensor and magnetic field tipper is obtained with EMpulse Geophysics’ proprietary Adaptive Polarization Stacking (APS) algorithm.

Technical
Channel Count: 8
A-D Resolution: 16 bit
Maximum Throughput: 1 MHz
Instrument Bandwidth: 8 Hz to 32 kHz
Analog Signal Flow:
- Switch selectable high input impedance buffer.
- AC coupled differential amplifier with shelf response, 3 levels, 6 dB steps.
- Active Twin-T notch filters, 1, 3, 5, 7 and 9’th harmonic of 50/60 Hz.
- Signal Mixer, three bands, 21 settings, 6 dB steps.
- Anti-alias filter, Butterworth type, 30 kHz corner.
- Differential output.
Power Consumption: 14 W
Power Supply: Nickel-Metal Hydride Battery Packs.
Case: High Impact ABS.
Weight: 12 kg
Acquisition Control and Data Storage: Military Spec. ruggedized laptop.

GRG-2 Field Feedback Induction Coil Magnetometer
Length: 99 cm
Diameter: 6 cm
Weight: 4 kg
Power consumption: 20 mA at ± 9 V DC
Bandwidth: 8 Hz - 40 kHz
Noise Floor: 2x10 at 2 kHz
Stability of Response: .015 percent /°C