# Doppler radar. Signal to noise ratio

I'm trying to figure out how a continuous wave Doppler radar works. When moving towards the radar, the Doppler frequency should increase, and when moving away from the radar, the frequency should decrease. I am using a microwave module at a frequency of 24 GHz. At "output I" I see a change in frequency depending on the speed of movement, but regardless of the direction of movement I will see the same frequency. The frequency varies only depending on the speed of movement. If I understand correctly, the movement in the direction from the radar is in the region of negative frequencies? If I want to split the direction of motion, then I should shift the signal to the right by multiplying the original signal by sin and cos?

I’m also interested in how to reduce the signal-to-noise ratio? Now I did it this way: I know that the movement speeds I need are in the range of 0.2-6m/s, which corresponds to a frequency of 32-966Hz. I broke down this range using bandpass filters 0-100, 100-200, 200-300, etc. The signal-to-noise ratio obtained in each range is better than when using the entire range of 32-966Hz. Are there any other solutions to improve the signal-to-noise ratio?

• "At 'output I' I see..." Output I of what? Different authors (or products) will use different terminologies. Please edit your question to cite your sources, or, if you're using a physical product, to tell us what the product is. Including a relevant and small quote of your source may be wise. Feb 17 at 17:05