Implementation of an AXI-compliant lock-in amplifier on the redpitaya open source instrument

This paper describe the implementation of a lock-in amplifier (LIA) which conforms to the AXI standard for on-chip communication. The design and implementation is based on the Zynq field programmable gate array (FPGA) present in the open-source instrument RedPitaya. The designed architecture is a mixed solution between VHDL hardware modules and software modules, running within an ARM CPU. General design criteria are summarized for the all-digital implementation. Simulation results for the performance of some of the designed intellectual property (IP) blocks are also presented to verify its operation.