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CPFSK Modulator Baseband

Modulate using continuous phase frequency shift keying method

Library

CPM, in Digital Baseband sublibrary of Modulation

  • CPFSK Modulator Baseband block

Description

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. TheM-ary numberparameter,M, represents the size of the input alphabet.Mmust have the form 2Kfor some positive integerK.

This block supports multi-hModulation index. SeeCPM Modulator Basebandfor details.

Integer-Valued Signals and Binary-Valued Signals

When you set theInput typeparameter toInteger, the block accepts odd integers between -(M-1) and M-1.

When you set theInput typeparameter toBit, the block accepts groupings ofKbits. Each grouping is called a binaryword. The input vector length must be an integer multiple ofK.

In binary input mode, the block maps each binary word to an integer between 0 and M-1, using a mapping scheme that depends on whether you set theSymbol set orderingparameter toBinaryorGray. The block then maps the integerkto the intermediate value 2k-(M-1) and proceeds as if it operates in the integer input mode. For more information, seeInteger-Valued Signals and Binary-Valued Signals.

This block accepts a scalar-valued or column vector input signal. If you setInput typetoBit,然后输入信号也可以vector of lengthK.

Single-Rate Processing

In single-rate 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 setInput typetoInteger, the input can be a column vector, the length of which is the number of input symbols.

  • When you setInput typetoBit, the input must be a column vector with a width that is an integer multiple ofK, the number of bits per symbol.

The output width equals the product of the number of input symbols and theSamples per symbolparameter value.

Multirate Processing

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 setInput typetoInteger, the input must be a scalar.

  • When you setInput typetoBit, the input width must equal the number of bits per symbol.

The output sample time equals the symbol period divided by theSamples per symbolparameter value.

Parameters

M-ary number

The size of the alphabet.

Input type

Indicates whether the input consists of integers or groups of bits.

Symbol set ordering

Determines how the block maps each group of input bits to a corresponding integer. This field is active only whenInput typeis set toBit.

Modulation index

Specify the modulation index {hi}. The default is0.5. The value of this property must be a real, nonnegative scalar or column vector.

This block supports multi-hModulation index. SeeCPM Modulator Basebandfor details.

Phase offset (rad)

The initial phase of the output waveform, measured in radians.

Samples per symbol

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 non-binary schemes, as defined by the pulse shapes, this value must be greater than 1.

For more information, seeUpsample Signals and Rate Changes.

Rate options

Select the rate processing option for the block.

  • Enforce single-rate 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 theSamples per symbolparameter 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 theSamples per symbolparameter value.

Output data type

Select the data type of the output signal. The output data type can besingleordouble.

Supported Data Types

Port Supported Data Types

Input

  • Double-precision floating point

  • Boolean (WhenInput typeset toBit)

  • 8-, 16-, and 32-bit signed integers (WhenInput typeset toInteger)

Output

  • Double-precision floating point

  • Single-precision floating point

References

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

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Introduced before R2006a

Communications Toolbox Documentation

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