I need to design a sine wave synthesizer for six channels. Each channel must have a different frequency and be an exact multiple of1Hz. Frequency ranges are from 100Hz to 1Khz.
I will do this by filtering out the harmonics of a square wave with an MAX294 switched capacitor filter:
Before I look into programing the dividers and timers into an FPGA to synthesize these 12 frequencies from a single reference frequency I am looking for off the shelf logic that can do this in just a few chips. What can you suggest?
The sine waves will be used to drive LEDs that illuminate optrodes. It is expected there will be a small amount of light crosstalking into the other channels. The crosstalk will be eliminated by FFT on the output of the photodiode's TIA. Maximum suppression of crosstalk will happen when the channel frequencies are a multiple of 1/T where T is the length of time the transform is done over. T can be 100 ms, 200 ms, 500 ms or 1 s.