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M-FSK Demodulator Baseband - Demodulate FSK-modulated data

Library

FM, in Digital Baseband sublibrary of Modulation

Description

The M-FSK Demodulator Baseband block demodulates a signal that was modulated using the M-ary frequency shift keying method. The input is a baseband representation of the modulated signal. The input and output for this block are discrete-time signals. The input can be either a scalar or a frame-based column vector of type single or double.

The M-ary number parameter, M, is the number of frequencies in the modulated signal. The Frequency separation parameter is the distance, in Hz, between successive frequencies of the modulated signal.

The M-FSK Demodulator Baseband block implements a non-coherent energy detector. To obtain the same BER performance as that of coherent FSK demodulation, use the CPFSK Demodulator Baseband block.

Binary or Integer Outputs

If the Output type parameter is set to Integer, then the block outputs integers between 0 and M-1.

If the Output type parameter is set to Bit and the M-ary number parameter has the form 2^K for some positive integer K, then the block outputs binary representations of integers between 0 and M-1. It outputs a group of K bits, called a binary word, for each symbol.

For boolean typed integer outputs, the M-ary number parameter must be 2. For Bit type outputs, the outputs must be of type boolean or double.

In binary output mode, the Symbol set ordering parameter indicates how the block maps an integer to a corresponding group of K output bits. See the reference pages for theM-FSK Modulator Baseband andM-PSK Modulator Baseband blocks for details.

Whether the output is an integer or a binary representation of an integer, the block maps the highest frequency to the integer 0 and maps the lowest frequency to the integer M-1. In baseband simulation, the lowest frequency is the negative frequency with the largest absolute value.

Dialog Box

M-ary number: The number of frequencies in the modulated signal.
Output type: Determines whether the output consists of integers or groups of bits. If this parameter is set to Bit, then the M-ary number parameter must be 2^K for some positive integer K.
Symbol set ordering: Determines how the block maps each integer to a group of output bits.
Frequency separation (Hz): The distance between successive frequencies in the modulated signal.
Samples per symbol: The number of input samples that represent each modulated symbol.
Output data type: The output type of the block can be specified here as boolean, int8, uint8, int16, uint16, int32, uint32, or double. By default, the block sets this to double.

Pair Block

M-FSK Modulator Baseband