Development of high sensitivity amplifier for VLF receiver application

In this paper, the development of amplifier based on AD744 monolithic Op-Amp is proposed for VLF receiver application. Due to the wide usage of very low frequency (VLF) wave for research on natural phenomena, a VLF receiver application particularly with high sensitivity is absolutely required. The proposed VLF amplifier which is intended to produce high sensitivity for the frequency range of 10–30kHz is designed to have an output connectable to the soundcard of personal computer for further data processing. After achieving the optimum design, the hardware realization is then implemented on a printed circuit board (PCB). From the measurement result, it shows that the sensitivity is almost linear for the input signal lower than −12dBm and becoming quadratic for the input signal higher than −12dBm.