info

The thermal noise object simulates the effects of receiver thermal noise on a complex baseband signal. Measuring the receiver thermal noise floor enables you to assess the minimum recoverable signal level of a receiver. Use the info object function to return the receiver thermal noise floor for the configured comm.ThermalNoise object.

Create a thermal noise object.

noise = comm.ThermalNoise( ...
    NoiseTemperature=290, ...
    ReferenceLoad=50, ...
    SampleRate=5e6)

noise = 
  comm.ThermalNoise with properties:

         NoiseMethod: 'Noise temperature'
    NoiseTemperature: 290
       ReferenceLoad: 50
          SampleRate: 5000000

Check the thermal noise object information.

info(noise)

ans = struct with fields:
    NoiseFloor: -119.9958

Apply thermal noise to a multichannel signal and confirm that each channel has the same noise floor as returned by the info object function.

Create a comm.ThermalNoise object.

tn = comm.ThermalNoise

tn = 
  comm.ThermalNoise with properties:

         NoiseMethod: 'Noise temperature'
    NoiseTemperature: 290
       ReferenceLoad: 1
          SampleRate: 1

Apply thermal noise to a multichannel signal and compute the signal variance for each channel.

x = tn(zeros(100000,3,'like',1i)); 
10*log10(var(x))

ans = 1×3

 -203.9973 -203.9684 -203.9802

Use the info object function to return the receiver thermal noise floor.

info(tn)

ans = struct with fields:
    NoiseFloor: -203.9752