The large spikes to the middle of the graph are modems transmitting back to the headend. The graph is from 5mhz to 42mhz (docsis specified return path) and reads from left to right. As you can see the lower the frequency (more towards the left) the more noisy it gets, which is normal to a point. However looking at the overall noise floor it looks high, that node probably wouldn't pass a DQM. Of course these are just my observations looking at a still picture Hard to say for sure without looking right at the analyzer.