| Abstract [eng] |
Lock-in amplifier – is an amplifier that can measure and extract faint signals from noisy environments or large signals over a wide dynamic range. High resolution is achieved due to its main principle – homodyne detection. Device under test is modulated at a known reference frequency via optical, electrical, or other type of signal. Its response is detected and transmitted as an electrical signal to one of lock-in amplifiers inputs where it is mixed with a reference signal. Mixed signal is filtered using a low-pass filter and the resulting value is a DC component which is directly proportional to the measured signal amplitude. The aim of this work is to design an FPGA-Based High Frequency Lock-in Detection System for Nonlinear Optical Microscopy. In this work a simulation of a lock-in amplifier was created and tested. The simulated design, by using VHDL hardware description language, was implemented, synthesized, and tested with a hardware description language simulation environment. Synthesized design was uploaded to DE0-Nano (Altera Cyclone IV EP4CE22F17C6N FPGA) development board and tested, by measuring its timing values and data output. Data output rates of up to 5MHz were achieved. |
