Abstract: Biomedical signals are of small amplitude and low frequency so that it is easily disturbed by the external environment, leading to superimpose a lot of noise. For the sake of increasing the accuracy of measurements, a pre-amplifier with good performance in order to extract biological signals effectively is proposed. The pre-amplifier is cascaded by instrumentation amplifier and variable gain amplifier so that it can achieve a signal amplification of 1000 times, and can achieve good performance. The simulation results indicate that the pre-amplifier has low equivalent input reference noise of 1.584 2 μV and low consumption of 2.92 μW under the operation voltage of 1 V, it is applicable in the field of biomedical signal acquisition.

Key words: low noise;low power consumption;biomedical signal;pre-amplifier