Table Of Contents

Binary MLS (G Dataflow)

Version:
    Last Modified: March 15, 2017

    Generates a maximum length sequence (MLS) of ones and zeros using a modulo-2 primitive polynomial of a specific order.

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    reset

    A Boolean that controls the reseeding of the noise sample generator after the first execution of the node. By default, this node maintains the initial internal seed state.

    True Accepts a new seed and begins producing noise samples based on the seed. If the given seed is less than or equal to 0, the node ignores a reset value of True and resumes producing noise samples as a continuation of the previous sequence.
    False Resumes producing noise samples as a continuation of the previous noise sequence. The node ignores new seed inputs while reset is False.

    Default: False

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    polynomial order

    Order of the modulo-2 primitive polynomial.

    If the input value is out of range, this node truncates the polynomial order to [3, 62].

    Default: 31

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    seed

    A number that initializes the noise generator.

    If reset is unwired, this node maintains the internal seed state.

    seed is greater than 0 Generates noise samples based on the given seed value. For multiple calls to the node, the node accepts or rejects new seed inputs based on the given reset value.
    seed is less than or equal to 0 Generates a random seed value and produces noise samples based on that seed value. For multiple calls to the node, if seed remains less than or equal to 0, the node ignores the reset input and produces noise samples as a continuation of the initial noise sequence.

    Default: -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.

    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.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

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    sample rate

    Sample rate in samples per second.

    This input is available only if you configure this node to return a waveform.

    Default: 1000

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    samples

    Number of samples in the signal.

    Default: 1000

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    t0

    Timestamp of the output signal. If this input is unwired, this node uses the current time as the timestamp of the output signal.

    This input is available only if you configure this node to return a waveform.

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    MLS

    The uniformly distributed, pseudorandom pattern.

    This output can return the following data types:

    • Waveform
    • 1D array of unsigned 8-bit integers
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    error out

    Error information.

    The node produces this output 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.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Algorithm for Calculating MLS

    This node uses a modulo-2 primitive polynomial to generate the binary Maximum Length Sequence (MLS). The MLS is periodic with a period of 2n - 1. Each period consists of 2n - 1 ones and 2n - 1 - 1 zeros, where n is the polynomial order. The MLS is spectrally flat, with a near-zero DC term.

    For example, if the polynomial order is 4, this node uses the polynomial g(p) = p4 + p + 1 to generate the MLS with a period of 15 in the following manner:

    where is the modulo-2 addition, and a0, a1, a2 and a3 are the shift registers.

    The following 15-point sequence comprises each period of the generated sequence: 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1. However, the starting point might be different for each sequence.

    The MLS is a type of Pseudo-Random Binary Sequence (PRBS).

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: This product does not support FPGA devices


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