TY  - JOUR
T1  - Fabrication of a Portable ULF Signal Receiver for Monitoring Electromagnetic Earthquake Precursors
AU - , A.A. Adetoyinbo AU - , O.I. Popoola AU - , O.S. Hammed AU - , A.A. Adeniran 
JO  - Online Journal of Earth Sciences
VL  - 2
IS  - 4
SP  - 113
EP  - 117
PY  - 2008
DA  - 2001/08/19
SN  - 1991-7708
DO  - ojesci.2008.113.117
UR  - https://makhillpublications.co/view-article.php?doi=ojesci.2008.113.117
KW  - Fabrication
KW  -portable ULF signal reciever
KW  -monitoring
KW  -electromagnetic
AB  - A portable Ultra Low Frequency (ULF) signal receiver, which can be made available in Physics laboratory was designed and fabricated for detection and identification of seismo electromagnetic signals that can be considered as precursory phenomena of earthquakes. The receiver circuit has four major sections that function as sophisticated signal processing and amplifier and powered by +5 to -5 V regulated source. A low pass  filter  circuit, in which a Butterworth filter was  the gate of the circuit, was employed to receive Ultra-Low Frequency  (ULF)  signals   of   desired   frequency.   The  frequencies of interest are  those  ranging  from  0.001-45 Hz. The desired frequencies then passed through a series of filters to remove transient noise, Electromagnetic Interferences (EMI) and 50 or 60 Hz frequency caused by commercial power, which could cluster the desired signal on the oscilloscope.
ER  -