RF_Pulse shapes and their corresponding Fourier Transforms.

• Author: Aditya Kumar
• Date: October 26th, 2015.

The following figures show the various RF pulse shapes available in bruker and their corresponding fourier transforms to gain an insight into the the process of slice selection. (The code for the first figure is shown.Please note the packages used.)

library(fftw)
library(waved)

## 
## Attaching package: 'waved'
## 
## The following object is masked from 'package:base':
## 
##     scale

gauss512 = read.table('D:/AK2_Phd/data/17p6_data/20151007/RawData/20151011_150604_surface_coil_1_2/Linear0_brukercombiner/3_gauss512_A30/spnam0', skip=15, sep=',')
gauss512$phase <- gauss512$V2*pi/180
gauss512$complex <- complex(real = gauss512$V1*cos(gauss512$phase), imaginary = gauss512$V1*sin(gauss512$phase))
gauss512$ft <- fftshift(FFT(gauss512$complex))
gauss512$ft_abs <- abs(gauss512$ft)
len <- length(gauss512$ft_abs)
par(mfrow = c(1,3))

plot(gauss512$V1*cos(gauss512$phase), main = expression(paste("Gauss 512 - Real Part,Rcos",phi)), xlab="Datapoints", ylab="pulse strength",type = "l")

plot(gauss512$V1*cos(gauss512$phase), main = expression(paste("Gauss 512 - Imag Part, Rsin",phi)), xlab='Datapoints', ylab='pulse strength',type = 'l')

plot(gauss512$ft_abs[(len/2-24):(len/2+24)], main = expression(paste("Gauss 512 - FFT (abs)")),xlab='Datapoints', ylab='Power',type = 'l')