This RLC meter design uses direct digital synthesis (DDS) techniques to generate the test waveform and digital signal processing (DSP) methods to condition the resulting voltage and current signals. Three test frequencies are implemented (100Hz, 1kHz, 10kHz) and both parallel and series circuit models are evaluated, automatic selection of both frequency and circuit model is available. Basic accuracy is better than 1%. Its handy user interface and graphic LCD make it easy to operate and read.
The prototype system is built using Microchip’s 16bit 28pin development board. It use Microchip’s USB PICKITII programmer to programming flash memory. Firmware code was written in C and compiled using the competition version of C30, developed in MPLAB v7.50. Coefficients for DSP filtering were created using Momentum Data Systems dsPIC FD Lite. The analog anti aliasing filters were designed with Microchip’s Filter Lab v2.0.
© Miguel Rusch
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