Abstract: We propose a design of applying delta-sigma modulation technique into digital output sensor’s signal detection circuit. A two-order 12-bit delta-sigma modulator is built by using adder, pre-amplifier, loop filter, ADC chip, DAC chip and feedback amplifier, so as to realize the detection of high-precision digital output sensor signals for temperature changes. Through theoretical analysis and transfer function derivation, we clarify that the signal detection circuit can suppress the quantization noise of the ADC chip and the non-ideal characteristics of the preamplifier. It also can reduce the background noise level of the circuit and obtain much higher resolution than the ADC and DAC chip in the delta-sigma modulation feedback loop. The simulation results show that the proposed design can directly convert the analog signal to be measured into high-quality digital signal output, and is expected to have a good application prospect in the field of sensor signal detection.

Key words: Delta-sigma modulation, Digital output sensor, Signal detection, Simulink simulation