Communications Blockset    
Phase Noise

Apply receiver phase noise to a complex baseband signal

Library

RF Impairments

Description

The Phase Noise block appies phase noise to a complex, baseband signal. The block applies the phase noise as follows:

  1. Generates additive white Gaussian noise (AWGN) and filters it with a digital filter.
  2. Adds the resulting noise to the angle component of the input signal.

You can view the block's implementation of phase noise by right-clicking on the block and selecting Look under mask from the pop-up menu. This displays the following figure:

You can view the construction of the Noise Source subsystem by double-clicking it.

The effects of changing the block's parameters are illustrated by the following scatter plots of a signal modulated by 16-ary quadrature amplitude modulation (QAM). The usual 16-ary QAM constellation without distortion is shown in the first scatter plot:

The following figure shows a scatter plot of an output signal, modulated by 16-ary QAM, from the Phase Noise block with Phase noise level (dBc/Hz) set to -70 and Frequency offset (Hz) set to 100:

This plot is generated by the model described in Scatter Plot Examples," with the following parameter settings for the Rectangular QAM Modulator Baseband block:

Dialog Box

Phase noise level (dBc/Hz)
Scalar specifying the phase noise level.
Frequency offset (Hz)
Scalar specifying the frequency offset in Hertz.
Initial seed
Nonnegative integer specifying the initial seed for the random number generator the block uses to generate noise.

See Also

Phase/Frequency Offset


  Phase-Locked Loop PM Demodulator Baseband