In order to realize consistency of acquisition channels of array receivers for Induced

polarization, it’s necessary to design a special calibration source . The induced polarization-similar

source based on US2.0 communications protocol was designed and implemented. This design is based

on the theoretical foundation of DDFS and uses field-programmable gate array to design core of DDFS,

with the generation of model sounding data. The induced polarization-simulated source can be

adjusted between 1uV and 1V with the step of 0.038V. The output of frequency is 1Hz, 0.25Hz,

0.125Hz, 0.0625Hz, while the error is 1.8 × 10-5 Hz. It has been applied in the main electromagnetic

probe system.