rwirelesscom (version 1.4.3)

eyediagram: Eye Diagram

Description

Receives a vector x of real or complex points and plots the Re or Im part of x in the form of an "eyediagram." The symbol period is indicated by the input Ns (samples per symbol) and horizontal sweep Np indicates the the number of symbol periods to plot along the horizontal access. The eyediagram is useful for evaluating inter-symbol interference associated with the in-phase or quadrature part of a modulated signal.

Usage

eyediagram(x, Ns = 1, Np = 3, No = 1, iq = "r", pch = 19, cex = 0.1, ...)

Arguments

x

- vector of real or complex points

Ns

- number of samples per symbol period

Np

- number of symbol periods to plot along the horizontal axis

No

- offset (n points) alignment of the eyediagram along the horizontal asis

iq

- parameter indicates whether to plot the in-phase Re(x) (iq="r" default) or quadrature Im(x) (iq="q")

pch

- Graphical parameter pch (plotting character) set to 19 by default ("point")

cex

- Graphical parameter cex magnificaiton of plotting symbols relative to 1 default set to 0.1.

...

- graphical environment parameters are input to eyediagram

See Also

Other rwirelesscom functions: f16pskdemod; f16pskmod; f16qamdemod; f16qammod; f64qamdemod; f64qammod; f8pskdemod; f8pskmod; fNo; fbpskdemod; fbpskmod; fqpskdemod; iqdensityplot; iqscatterplot; stemplot

Examples

# Step 1: generate random set of bits
M=4
Nsymbols=10000
Nbits=log2(M)*Nsymbols
bits <- sample(0:1,Nbits, replace=TRUE)

# Step 2: Generate a BPSK modulated signal including raised cosine
#  pulse shaping sampled at 64 samples per symbol period and roll-off
#  factor of 0.5.
Ns=64
B=0.5
hx=seq(-4*Ns,4*Ns,by=1)
h=rcosine(hx,B,Ns)
s <- fqpskmod(bits,Ns,h)

# Step 3: Plot the transmitted waveform with the eyediagram function.
#    Remove the initial 1000 and tail points for a cleaner diagram, i.e.
#    without startup and tail artifacts
Np=3
No=27

# real part (in-phase)
eyediagram(s[1000:60000],Ns,Np,No,iq="r",xlab="Ts",ylab="I")
# imaginary part (quadrature)
eyediagram(s[1000:60000],Ns,Np,No,iq="q",xlab="Ts",ylab="Q")