Modulate using differentially encoded minimum shift keying method
CPM, in Digital Baseband sublibrary of Modulation
The MSK Modulator Baseband block modulates using the differentially encoded minimum shift keying method. The output is a baseband representation of the modulated signal.
This block accepts a scalarvalued or column vector input signal. For a column vector input signal, the width of the output equals the product of the number of symbols and the value for the Samples per symbol parameter.
Differentially encoded minimum shift keying modulation uses pulse shaping to smooth the phase transitions of the modulated signal. The function q(t) is the phase response obtained from the frequency pulse, g(t), through this relation:
The specified frequency pulse shape corresponds to this rectangular pulse shape expression, g(t).
Pulse Shape  Expression 

Rectangular 
L_{main} is the main lobe pulse duration in symbol intervals.
The duration of the pulse, LT, is the pulse length in symbol intervals.
When you set the Input type parameter to
Integer
, then the block accepts values of 1 and
1.
When you set the Input type parameter to
Bit
, then the block accepts values of 0 and 1.
For information about the data types each block port supports, see the Supported Data Types table on this page.
In singlerate processing mode, the input and output signals have the same port sample time. The block implicitly implements the rate change by making a size change at the output when compared to the input. In this mode, the input to the block can be multiple symbols.
When you set Input type to
Integer
, the input can be a column vector,
the length of which is the number of input symbols.
When you set Input type to
Bit
, the input width must be an integer
multiple of K, the number of bits per symbol.
The output width equals the product of the number of input symbols and the Samples per symbol parameter value.
In multirate processing mode, the input and output signals have different port sample times. In this mode, the input to the block must be one symbol.
When you set Input type to
Integer
, the input must be a scalar.
When you set Input type to
Bit
, the input width must equal the number of
bits per symbol.
The output sample time equals the symbol period divided by the Samples per symbol parameter value.
Indicates whether the input consists of bipolar or binary values.
The initial phase of the output waveform, measured in radians.
The number of output samples that the block produces for each integer or binary word in the input, which must be a positive integer. For all nonbinary schemes, as defined by the pulse shapes, this value must be greater than 1.
For more information, see Upsample Signals and Rate Changes in Communications Toolbox™User's Guide.
Select the rate processing option for the block.
Enforce singlerate processing
—
When you select this option, the input and output signals have the
same port sample time. The block implements the rate change by making
a size change at the output when compared to the input. The output
width equals the product of the number of symbols and the Samples
per symbol parameter value.
Allow multirate processing
—
When you select this option, the input and output signals have different
port sample times. The output sample time equals the symbol period
divided by the Samples per symbol parameter value.
Specify the block output data type as double
and
single
. By default, the block sets this to
double
.
Port  Supported Data Types 

Input 

Output 

[1] Anderson, John B., Tor Aulin, and CarlErik Sundberg, Digital Phase Modulation, New York, Plenum Press, 1986.