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.