MPSK Modulator Baseband
Modulate using Mary phase shift keying
Libraries:
Communications Toolbox /
Modulation /
Digital Baseband Modulation /
PM
Communications Toolbox HDL Support /
Modulation /
PM
Description
The MPSK Modulator Baseband block modulates an input signal using Mary phase shift keying (PSK) and returns a complex baseband output. The modulation order, M, which is equivalent to the number of points in the signal constellation, is determined by the Mary number parameter. The block accepts scalar or column vector input signals.
Examples
Ports
Input
Output
Parameters
Block Characteristics
Data Types 

Multidimensional Signals 

VariableSize Signals 

^{a} ufix(1) at the input if ''input type'' is set to ''bit''. ufix(ceil(log2(M))) at input if ''input type'' is set to ''integer'' for Mary modulation. ^{b} Fixedpoint outputs must be signed. 
Algorithms
For binaryencoding, the output baseband signal maps input bits or integers to complex symbols according to:
$${s}_{n}(t)=\mathrm{exp}\left(j\pi \left(\frac{2n+1}{M}\right)\right);\text{\hspace{1em}}n\in \{0,1,\dots ,M1\}.$$
When the input is configured for bits, groups of log_{2}(M) bits represent the complex symbols for the configured symbol mapping. The mapping can be binary encoded, Gray encoded, or custom encoded.
Gray coding has the advantage that only one bit changes between adjacent constellation points, which results in better bit error rate performance. This table shows the mapping between the input and output symbols for 8PSK modulation with Gray coding.
Input  Output 

0  0 (000) 
1  1 (001) 
2  3 (011) 
3  2 (010) 
4  6 (110) 
5  7 (111) 
6  5 (101) 
7  4 (100) 
This constellation diagram shows the corresponding symbols and their binary values.
References
[1] Proakis, John G. Digital Communications. 4th ed. New York: McGraw Hill, 2001.
Extended Capabilities
Version History
Introduced before R2006a