Modulate using continuous phase frequency shift keying method
CPM, in Digital Baseband sublibrary of Modulation
The CPFSK Modulator Baseband block modulates a signal using the continuous phase frequency shift keying method. The output is a baseband representation of the modulated signal. The Mary number parameter, M, represents the size of the input alphabet. M must have the form 2^{K} for some positive integer K.
This block supports multih Modulation index. See CPM Modulator Baseband for details.
When you set the Input type parameter to Integer
,
the block accepts odd integers between (M1) and M1.
When you set the Input type parameter to Bit
,
the block accepts groupings of K bits. Each grouping
is called a binary word. The input vector length
must be an integer multiple of K.
In binary input mode, the block maps each binary word to an
integer between 0 and M1, using a mapping scheme that depends on
whether you set the Symbol set ordering parameter
to Binary
or Gray
.
The block then maps the integer k to the intermediate
value 2k(M1) and proceeds as if it operates in the integer input
mode. For more information, see IntegerValued Signals and BinaryValued Signals in Communications System Toolbox™ User's
Guide.
This block accepts a scalarvalued or column vector input signal.
If you set Input type to Bit
,
then the input signal can also be a vector of length K.
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 must be a column vector with a width that is 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.
The size of the alphabet.
Indicates whether the input consists of integers or groups of bits.
Determines how the block maps each group of input bits to a
corresponding integer. This field is active only when Input
type is set to Bit
.
Specify the modulation index {h_{i}}. The
default is 0.5
. The value of this property must
be a real, nonnegative scalar or column vector.
This block supports multih Modulation index. See CPM Modulator Baseband for details.
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 System ToolboxUser'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.
Note:
The option 
Select the data type of the output signal. The output data type
can be single
or double
.
Port  Supported Data Types 

Input 

Output 

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