We are currently looking into spectrum analysis to find the resonant frequency of a wire.

The frequency range we are targeting is 1 kHz to 3 kHz so I will be using a sample rate of about 11025 Hz.

Since we are chasing 0.001Hz resolution I will have an array length of approximately 11.025e6 elements.

I estimate that about 22000 million cycles of the DFT loop (not calculated how many machine cycles in each loop) will be required which I estimate to be too much for many MCU's to perform in the required time frame of 1 minute. In an ideal world we would take a new sample every 1 or 2 minutes.

Does anyone know of a DSP that would do the task with such a large array length?