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Receives a sequence of data bits, performs FSK modulation, and returns the modulated complex baseband waveform in the output complex waveform parameter.

Note  

If you use the finite impulse response pulse-shaping filters in modulation nodes, it may lead to the apparent loss of bits caused by filter delay. Refer to Filter Delay in the Details for more information about this effect. Set the flush buffers? parameter to TRUE to offset the effects of filter delay in single-shot operations or in the last iteration of continuous operations.

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input bit stream

The sequence of information bits to be modulated.

Note  

For FSK systems with more than 1 bit per symbol, such as 4-FSK, the symbols are converted to bits in least significant bit (LSB) first order. For example, if the detected symbols are 2,1,... the generated bits are 0,1,1,0...

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FSK system parameters

Parameter values defining the FSK system. Wire the FSK system parameters cluster returned from MT Generate FSK System Parameters (M) or MT Generate FSK System Parameters (map) to this cluster. Do not alter the values.

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samples per symbol

An even number of samples dedicated to each symbol. Multiply this value by the symbol rate to determine the sample rate.

Note  

The demodulation and detector nodes use timing recovery, which is optimized for four or more samples per symbol.

Default: 16

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symbol map

An ordered array that maps each Boolean symbol to its desired deviation frequency. The number of FSK levels in the array is 2 N , where N is the number of bits per symbol.

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symbol phase continuity

Continuity of phase transitions between symbols.

continuous

Continuous phase transitions between symbols.

discontinuous

Discontinuous phase transitions between symbols, that is, discontinuous phase FSK (DPFSK).

With discontinuous phase-FSK (DPFSK), modulation consists of selecting the appropriate sinusoid based on the input data. Thus, when switching between symbols, there is a discontinuity in the FSK signal phase. To emulate a hardware-based DPFSK source, this node maintains the phase of each independent sinusoid versus time. Thus, the DPFSK modulator acts like a hardware-based (multiple switched tone generator) FSK modulator.

Default: continuous

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symbol rate

The desired symbol rate, in hertz (Hz).

Default: 1.0

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pulse shaping filter coefficients

An ordered array containing the desired pulse-shaping coefficients. Wire the pulse shaping filter coefficients parameter of MT Generate Filter Coefficients to this parameter. When generating the filter coefficients, ensure that the value of the pulse shaping samples per symbol parameter of MT Generate Filter Coefficients is equal to the value of the samples per symbol element of the FSK system parameters cluster which is passed to this node.

Note  

When you configure reset? to TRUE, there is a transient response of half the filter length at the start of the modulated signal, and the returned output data is shortened by approximately half the filter length. When you configure reset? to FALSE, the node uses data from the previous iteration to eliminate the transient.

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error in

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

Default: no error

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reset?

A Boolean that determines whether the node continues modulating using the previous iteration states. The node resets on the first call and when you configure reset? to TRUE. You must configure reset? to TRUE the first time this node is called and whenever you want to restart the modulator.

Default: TRUE

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flush buffers?

A Boolean that determines whether samples are forced out from the modulated waveform that are affected by the FIR pulse-shaping filter delay. Set this parameter to TRUE during single-shot operations and during the last iteration of continuous operations.

TRUE Destroys the internal states of the algorithms such that you cannot perform continuous processing on the signal during subsequent iterations. If flush buffers? is set to TRUE, you must set reset? to TRUE on the subsequent iteration.
FALSE Stores the internal states of the algorithms so that you can perform continuous processing on the signal during subsequent iterations.

Default: FALSE

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output complex waveform

The modulated complex baseband waveform data.

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t0

Time of the first value in the Y array.

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dt

Time interval between data values in the Y array.

Default: 1.0

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Y

The complex-valued signal-only baseband modulated waveform. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively.

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symbols out

The array of mapped symbols before pulse shaping is applied. The real portion corresponds to the carrier frequency offset of the mapped symbol, and the imaginary portion is zero.

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error out

Error information. The node produces this output according to standard error behavior.