Sampling signal after root raised cosine

1. Why it is necessary to apply a raised cosine filter before passing the signal onto the channel?
2. Why use root raised cosine?
3. What is the outcome of increasing the roll off factor of a raised cosine filter on overcoming the problem of ISI?
4. What is raised cosine spectrum?

Why it is necessary to apply a raised cosine filter before passing the signal onto the channel?

Raised cosine filters are used for pulse shaping, where the signal is upsampled. Therefore, we also need to specify the upsampling factor.

Why use root raised cosine?

Using 90% power Bandwidth (BW) measurement definition showed that the RRC filtering might improve spectrum efficiency by more than 75%. Furthermore using the matching RRC filters both in the transmitter and receiver provides the improved Bit Error Rate (BER) performance.

What is the outcome of increasing the roll off factor of a raised cosine filter on overcoming the problem of ISI?

Explanation: As the rolloff factor increases, the bandwidth of the filter also increases and the time sidelobe levels decrease in adjacent symbol slots. Thus, it implies that increasing rolloff factor decreases the sensitivity to timing jitter but increases the occupied bandwidth.

What is raised cosine spectrum?

The raised-cosine filter is a filter frequently used for pulse-shaping in digital modulation due to its ability to minimise intersymbol interference (ISI). Its name stems from the fact that the non-zero portion of the frequency spectrum of its simplest form ( ) is a cosine function, 'raised' up to sit above the.