The term coded refers to the presence of error correction coding scheme involving the use of redundant bits and expanded bandwidth.

When the output is quantized for more than two levels, soft decision is made.

The basic ways to increase the throughput of the system is to increase the EIRP, by reducing the system losses, providing channel bandwidth, and efficient allocation of CR.

The bandwidth efficiency R/W increases as M increases in case of MPSK modulation.

The relationship between symbol transmission rate and data rate R is given by Rs= R/log2M.

The rate of code is given as k/n and its inverse n/k gives the redundancy of the code.

For an uncoded system, if the channel is power limited MFSK is selected and if it is bandwidth limited MPSK is selected.

In space division multiplexing, spot beam antennas are used to separate radio signals by pointing in different directions.

Any digital communication system will become more bandwidth efficient as its WTb product decreases.

In MFSK, the denominator increases faster as the numerator when M increases. Thus R/W decreases with increase in M.