To improve stability of the signal source and perform sweeping detection, as well as extract abundance and reliable signal, the direct digital synthesis technology was employed to design the generator of source which formes a sweeping frequencies sine wave output from 1 MHz to 20 MHz. The planar spiral coil was connected as an amplitude modulation circuit. The same coil was made use of differential architecture for signal detection and extraction. The MC1595 was utilized to compose a phase detector, in which difference of phases varies with change of frequencies. A low pass filter was designed to filter the carry waves of the sweeping source. Thereby the system obtained abundance data and its stability was improved. Further, the spatial resolution of the system was enhanced. All of the above is in favor of using software in magnetic focused conductivity tomography system to reconstruct the image of conductivity within human body.
