MATLAB Functions in Communications - 1

1) taylorwin

Taylor window

Syntax:

w = taylorwin(L)
w = taylorwin(L,nbar)
w = taylorwin(L,nbar,sll)

calculates the amplitude coefficients for the antenna elements by applying a Taylor taper. L is the no. of antenna elements, nbar is the no. of side lobes, sll is the side lobe level in dB (-ive value).

Description: 

Taylor windows are similar to Chebyshev windows. While a Chebyshev window has the narrowest possible mainlobe for a specified sidelobe level, a Taylor window allows you to make tradeoffs between the mainlobe width (HPBW) and sidelobe level. Taylor window coefficients are not normalized. Taylor windows are typically used in radar applications, such as weighting synthetic aperature radar images and antenna design.

2) awgn

Add white Gaussian noise to signal

Syntax:

y = awgn(x,snr)

Description:

Additive white Gaussian noise (AWGN) is a channel model in which the only impairment to communication is a linear addition of wideband or white noise with a constant spectral density and a Gaussian distribution of amplitude. The command adds white Gaussian noise to the vector signal x. The scalar snr specifies the signal-to-noise ratio per sample, in dB. If x is complex, awgn adds complex noise. This syntax assumes that the power of x is 0 dBW.

For Details:

http://www.mathworks.com/help/toolbox/signal/taylorwin.html
http://www.mathworks.com/help/toolbox/comm/ref/awgn.html