From 12:00 PM - 8:00 PM CST on Thursday, October 18, ni.com will be undergoing system upgrades that may result in temporary service interruption.

We appreciate your patience as we improve our online experience.

From 12:00 PM - 8:00 PM CST on Thursday, October 18, ni.com will be undergoing system upgrades that may result in temporary service interruption.

We appreciate your patience as we improve our online experience.

Last Modified: January 9, 2017

Calculates parameters for use with either MT Modulate FSK or MT Demodulate FSK. This node accepts an input array of **symbol values** that explicitly specifies the positions of the symbol map.

Array of symbol values with an order that corresponds to the symbol map. The number of FSK levels specified in the array must be 2^{ N }, where *N* is the number of bits per symbol.

This parameter expects an array of integers. The integers 0 to (*M*-1), inclusive, must all be included only once in the **symbol values** array, where *M* is the *M*-ary number of the modulation. The symbol locations (FSK frequencies) are evenly spaced between -*FSK* Deviation and +*FSK* Deviation, inclusive, with the binary representation (LSB first convention) of the integers that populate the **symbol values** array that corresponds to the placement of the *M*-ary bits on the I/Q constellation.

For example, for 4-FSK, if you specify **FSK deviation** as 150k and **symbol values** as [0 1 3 2], then:

- 00 (symbol value 0) corresponds to -150k
- 01 (symbol value 1) corresponds to -50k
- 11 (symbol value 3) corresponds to 50k
- 10 (symbol value 2) corresponds to 150k

Therefore the generated FSK symbol map reads [-150k -50k 150k 50k]. Similarly, if you specify the **symbol values** array as [0 1 2 3], the generated FSK symbol map reads [-150k -50k 50k 150k].

Maximum FSK frequency deviation. At baseband frequencies, deviations for individual symbols are evenly spaced in the interval [-*f* _{ d }, *f* _{ d }], where *f* _{ d } represents the frequency deviation.

**Default: **150,000

Continuity of phase transitions between symbols.

Name | Description |
---|---|

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**

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

**Default: **no error

Parameter values defining the FSK system. Wire this cluster to the corresponding **system parameters** cluster of MT Modulate FSK or MT Demodulate FSK.

Number of samples per symbol in the modulated output complex waveform. For error-free operation, the **samples per symbol** must be an even number. Applying Carson's rule for FSK modulation, the 98% FSK bandwidth is given by the following formula:

0.5 × (1 + *r*) × *symbol rate* + *peak frequency deviation*

where 0 ≤ *r* ≤ 1 is the filter parameter.

To satisfy the Nyquist criterion, use the following guideline.

*samples per symbol* = 2 × ceil(1.5 × *bandwidth/symbol rate*) to obtain 3× oversampling.

Ordered array that maps each Boolean symbol to its desired deviation frequency. The number of FSK levels in the array must be 2^{ N }, where *N* is the number of bits per symbol.

Continuity of phase transitions between symbols.

Name | Description |
---|---|

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**

Number of bits represented by each symbol. This value is equal to Log_{ 2 }(*M*), where *M* is the order of the modulation. Example: For 16-FSK, *M* = 16.

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: Not supported