Noise reduction in current spectrum collected using SPI Interface

Some questions if I may: 1. How many analog channels are you recording? 2. What microcontroller are you using? 3. What physical variable are you measuring? (temperature / humidity / something else?) 4. What sample rate (approximately) are you currently using? It would help if you could share a schematic and / or your current source code. I have experience with STM32, PIC and AVR microcontrollers, but not with - e.g. - Texas instruments or LPC microcontrollers. It is difficult to suggest a method of noise reduction without knowing more about the variable being measured and the environment the device will be operating in. And it is difficult to make an accurate bid until I have more information. In the meantime, please note that this bid is PROVISIONAL. I may need to adjust the price and / or timeframe. I am based in Ireland. Please note the timezone difference with India. P.S. If this is a college project or assignment then please don't waste my time. I will not facilitate plagiarism.

I understand your requirement as "to read the ADC data periodically or on interrupt based, and apply filtering/signal processing on the results" to get desired output. I have lot of experience in embedded system development including ADC & SPI. If you provide more details about your requirement, then I can give a detailed proposal.