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Timing Error

The following binary signal set is used to transmit equally likely messages over an additive white Gaussian noise channel (spectral height $\frac{N_0}{2}$),

\begin{displaymath}
\begin{array}
{cl}
 s_0(t) = & \left\{ 
 \begin{array}
{cl}
...
 ...q t \leq T$}\\  0 & \mbox{else}
 \end{array} \right.\end{array}\end{displaymath}

1.
Draw a block diagram of the optimum receiver which uses only a single correlator.
2.
Compute the probability of error for this receiver.
3.
Assume now that a receiver is used whose bit timing is off by $\tau$ seconds, such that the integration period is from $\tau$ to $T+\tau$. You may assume $\tau \gt$. The resulting receiver is shown below.


\begin{picture}
(100,30)
 
\setlength {\unitlength}{1mm}
 %
 \put(0,10){\vector(...
 ...akebox(30,7){if $R < 1$, say $s_1$}}
 \put(90,10){\vector(1,0){10}}\end{picture}

Compute the conditional probabilities, fR|b=0 and fR|b=1 as a function of the timing error $\tau$.

4.
Compute the probability of error as a function of the timing error $\tau$. How does the timing error affect performance relative to the optimum receiver?


Prof. Bernd-Peter Paris
3/3/1998