Design and simulation of digital lock-in amplifier based on the DSP Builder

In the design of gas detection system, in order to eliminate 1/f noise and other strong noises, the solution is usually to adopt a modulated light source and a phase-locked detection system. Therefore, for detecting harmonics signal after gas absorption, we has designed and simulated the digital lock-in amplifier with DSP Builder on the basis of the principle of the lock-in amplifier. Through checking out the existing problem with the initial design using the DSP Builder, we modify the design and finally obtain the optimal parameters. Simulation results show that the designed digital lock-in amplifier can remove the noises by applying the correlation detection approach.