Paper
6 July 2000 Multifrequency EM image system
Qing Zhang, Xuemin Chen, Xuhan Jiang, C. Richard Liu
Author Affiliations +
Abstract
A digital, multi-frequency EM image system is developed based on the induction principle for subsurface imaging near a sewage pipe. This system, which features a broadband operation, can transmit sinusoidal in a frequency range of 1.25 KHz to 10 KHz. A micro controller is used for all controls and computations for both the transmitter and receiver circuits. Synchronous sampling is used for digitization in order to compute the phase as well as the amplitude of the receiving signal. The system operates in the frequency domain and both the phase and amplitude information can be computed through a DSP algorithm. Test results indicate that the multi-frequency EM sensor is superior in both the missing manhole detection and general subsurface conductivity imaging to the conventional single- frequency sensors. For loop antennas with a spacing of 0.5 m, the system has phase resolution about 1 degree(s) and amplitude resolution about 0.5 percent.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Qing Zhang, Xuemin Chen, Xuhan Jiang, and C. Richard Liu "Multifrequency EM image system", Proc. SPIE 4129, Subsurface Sensing Technologies and Applications II, (6 July 2000); https://doi.org/10.1117/12.390632
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Sensors

Receivers

Antennas

Digital signal processing

Fourier transforms

Signal detection

Transmitters

Back to Top