Minimum-Shift Keying (MSK)

As discussed in class, MSK is full response, continuous phase modulation with modulation index $h=\frac{1}{2}$, using rectangular pulse-shaping.

1. Draw and accurately label a block diagram for a MSK transmitter which indicates clearly how the transmitted signal is generated from the sequence of input bits.
2. Sketch the baseband equivalent (magnitude and phase) MSK signal for the input sequence $\{1,-1,1,1,-1,-1\}$.
3. Draw a block diagram of the receiver which minimizes the probability of error if a coherent phase reference is available. Compute the probability of error achievable with this receiver.
4. Is it possible to use a non-coherent receiver with MSK, i.e., a receiver which does not require knowledge of the phase of the received signal? If your answer is no, explain why not. If your answer is yes, draw a block diagram of the non-coherent detector.
5. Gaussian Minimum Shift Keying (GMSK) employs a Gaussian pulse for filtering the input sequence. Draw a block diagram of the transmitter for GMSK which shows clearly where the Gaussian filter is located.
6. Explain the influence of this filter on system parameters such as bandwidth and error rate and discuss how the receiver must be modified to reflect the influence of the Gaussian filter.