# Plot Background Noise

I am a total newbie in signal processing. I have been trying to plot on simulink a time/frequency domain noise in PLC (Powerline Communication) that matches a real-world research "Time Frequency Analysis of Noise Generated by Electrical Loads in PLC", however, I failed to plot such noise.

Generally speaking about my aim, I am trying to collect appliances’ noise that causes bit errors in PLC by comparing the original bit sequence with the received bit sequence. So, I need to simulate each appliance noise individually like the article mentioned above. Unfortunately, I couldn’t find any data source where I could download appliances’ noise, so I am creating my own simulation to collect my appliances’ bit-errors data. I have been able to simulate PLC using FSK modulation/demodulation with 1000 bits per second as a binary sample rate for my bit-sequence. For the FSK modulation, I have 7500 Hz as a carrier frequency for the bit-sequence to the AC channel that has 50 Hz/220 V as the typical AC source voltage, but now I am stuck on the phase of creating Appliances’ noise which has to matches real-world noise.

If anyone knows how to plot on Simulink as I don't know how to plot such signals:

• In frequency domain: background noise as high as 55dB for the measurement frequency range with the power contained up to 4MHz
• In time domain: Raise up to 45dB above the background noise floor for most of the AC cycle duration

As far as the article shows, it should look like this.

I need to plot a huge dataset, so if anyone could help me understand how to plot such noise, I will be able to plot the rest.

• I don't understand your question: You have three plots. They do look like they are what you need. (aside from the third plot, whose x-Axis label and y-Axis label make no sense together). Can you explain your signal processing problem in more detail? What's wrong? Jun 10, 2018 at 10:09
• @MarcusMüller I need to create a noise plot with a certain PSD (power spectral density) for each appliance as some powerline appliances induce a certain range of change in dB. I really don't understand that much in Signal Processing, that's why I needed help here. Jun 10, 2018 at 10:37
• Yes, but you're not asking a question that we can answer. I mean, your tool has some plotting functions; so, use them! We know nothing about the kind of data you have, so we really can't help you with the amount of info you're giving us. Jun 10, 2018 at 10:40