Version:

Last Modified: February 7, 2018

Maps an incoming bit stream to complex-valued PSK symbols.

Use this node in conjunction with
MT Matched Filter,
MT Align to Ideal Symbols,
MT Decimate Oversampled Waveform, and
MT Calculate BER to perform waveform analysis on the modulated waveform.
**Note**

The mapping of symbols to bits depends on the number of bits per symbol, which equals
${\mathrm{log}}_{2}\left(M\right)$ with *M* representing the size of the modulation scheme. For example, in a 256-QAM system, 500 QAM symbols are mapped to
$\left(500\right)\times {\mathrm{log}}_{2}\left(256\right)=4000\text{\hspace{0.17em}}\text{\hspace{0.17em}}message\text{\hspace{0.17em}}\text{\hspace{0.17em}}\text{\hspace{0.17em}}bits$.

The incoming bit stream to be mapped to symbols.

An ordered array that maps each Boolean symbol to its desired coordinates in the complex plane. The number of PSK states in the array must be 2^{ N }, where *N* is the number of bits per symbol.

Type of PSK modulation.

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

normal | Sets the modulation type to regular PSK. |

shifted | Rotates the constellation by $\pi $/M each symbol. |

offset | Sets the modulation type to offset quadrature phase-shift keying (OQPSK). This modulation scheme is a form of phase-shift keying in which four different phase angles are used. This scheme is sometimes referred to as staggered quadrature phase-shift keying (SQPSK). For offset PSK, the ideal symbol timing for Q is offset by 1/2 of a symbol period from the ideal symbol timing for I. |

**Default: ****normal**

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an **error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

**Default: **No error

A value that indicates how the PSK modulation represents symbols.

Differential operation is used to implement PSK formats such as differential quadrature PSK (DQPSK) and $\pi $/4-DQPSK.

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

disable | Symbols are represented as constellation points. |

enable | Symbols are represented as the transitions between constellation points. |

**Default: ****disable**

A Boolean that determines whether stored state information is cleared on each call to this node.

When the **input bit stream** is not comprised of an integer number of symbols, the carryover bits are buffered.

TRUE | Clears the buffered data, checks the input parameters on a first call, and reflects any change in the input parameter values during subsequent iterations. |

FALSE | Adds the buffered data to the beginning of data from next iteration, in continuous operations. |

**Default: **TRUE

An array of complex-valued PSK symbols with a one-to-one mapping to the **input bit stream** based on the specified PSK **symbol map**.

When you configure **PSK type** to **shifted**, the mapped symbols are additionally multiplied by the complex phasor, as shown by the following equation:

${e}^{jm\frac{\pi}{M}},m=\text{\hspace{0.17em}}\mathrm{0...}M-\text{\hspace{0.17em}}1,\text{\hspace{0.17em}}j=\text{\hspace{0.17em}}\sqrt{1}$

where *M* specifies the *M*-ary PSK format. This multiplication ensures that the generated PSK oversampled waveform never transitions through the origin after pulse shaping.

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

**error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application