High Precision Signal Acquisition System for Magnetoresistive Magnetometer

As a new magnetic field measurement technology, magnetoresistive magnetometer has the absolute advantages in weight, power consumption and size, and plays an irreplaceable role in many fields. Because the data acquisition of the magnetoresistive magnetometer rely on ADC, So the paper presents the circuit design of a high-precision signal acquisition system based on sigma-delta ADC for magnetoresistive magnetometer. In this design, FPGA is adopted as the core controller of the system to control the read and write of six AD7710, it also completes receiving, caching, and sending ADC sampling data. The system self-test results show that the noise RMS value of the sampled data is 0.0019 mV when the sampling frequency is selected as 30 Hz, which is better than the typical output RMS noise value of the device.