CNR vs SNR – What’s the difference?
CNR, CN Ratio, stands for Carrier to Noise Ratio and is measured AFTER modulation. It is a measure of the received carrier strength relative to the strength of the received noise.
SNR, SN Ratio, stands for Signal to Noise Ratio and is measured BEFORE modulation. It is a measure of signal strength relative to background noise.
CNR vs SNR, what are they actually used for and how do they work?
CNR
The CN ratio can be said to be the proportion of how much “raw signal” you have vs how much noise there is. The CN ratio is very easy to get as all you have to do is to find a carrier and measure its strength. Alternatively, you can measure the strength of adjacent frequencies to get the noise level without the carrier wave.
The CN ratio is important as it gives you raw measurements of how well things are going to travel over a wire. It is measured in dB, and the higher it is, the better!
SNR
The SN ratio is the more important measurement of digital signals and is derived by tuning the signal and determining how much of it is “total rubbish”. SNR tells you how much more usable signal you have than non-usable signal.
The key with SNR is that it’s strong at the antenna and won’t get weaker once it arrives at the television.
What can cause bad CN and SN ratios?
CNR drops the further away from the towers you are, or if the signal is in some way, shape, or form blocked.
SNR also drops in the same way but is also affected by electromagnetic interference.
What’s a CNR generator?
A CNR generator is a device that measures the power level across frequence bands. It generates a CN ratio based on the average power across the band. They are mostly used by design, system and test engineers in the field of cellular, military and satellite communications and offer an efficient and cost-effective method of obtaining an increasingly higher yield. This is enabled through the means of automated testing which gives better results thanks to repeatable and accurate settings of the carrier to noise generator.
