Table Of Contents

MT Generate PAM System Parameters (map) (G Dataflow)

Last Modified: January 9, 2017

Calculates parameters for use with either MT Modulate PAM or MT Demodulate PAM. The node accepts an array of symbol values that explicitly specifies the positions of the symbol map with symbols that are evenly distributed between -1 and 1.

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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.

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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 values

An array of symbol values with an index-based order that corresponds to the symbol map. The length of the symbol values array must be a positive power of 2, and the entries must be unique and in the range 0 to M-1, where M is the length of the symbol values array.

This node expects an array of integers for the symbol values parameter. The integers 0 through (M-1) must all be included only once in the symbol values array, where M is the M-ary number of the modulation. The binary representation (LSB first convention) of the integers represents the bit pattern that is mapped to the corresponding symbol location in the symbol values array. The symbol locations are evenly spaced between (-1 + 0i) and (1 + 0i), inclusive, along the real axis (I axis).

For example, for 4-PAM, if you specify symbol values as [2 3 0 1], the generated PAM symbol map is [(0.333 + 0i), (1 + 0i), (-1 + 0i), (-0.333 + 0i)].

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Note  

An entry at index n is mapped to the PAM symbol map at location 2n/(M - 1)- 1, where M is the size of the PAM constellation. For example, if you specify a symbol values array with entries [0, 1, 2, 3], the symbol-to-symbol pairing is symbol 0 level -1, symbol 1 level -1/3, symbol 2 level 1/3, symbol 3 level 1.

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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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PAM system parameters

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

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samples per symbol

Number of samples per symbol in the modulated output complex waveform. For error-free operation, the samples per symbol must be an even number.

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symbol map

An ordered array that maps each symbol to its desired level. The number of PAM levels in the array is 2 N , where N is the number of bits per symbol. The vector length for the symbols farthest from the origin is 1.

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bits per symbol

Number of bits represented by each symbol. This value is equal to Log 2 (M), where M is the order of the modulation (for example, for 16-PAM, M = 16).

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error out

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

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported


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