# 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? – Marcus Müller Jun 10 '18 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. – debugging XD Jun 10 '18 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. – Marcus Müller Jun 10 '18 at 10:40