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MT Convolutional Encoder (Rate) (G Dataflow)

Last Modified: January 9, 2017

Generates an encoded bit stream based on a code rate that you select. The code rate is equal to the ratio of the data word length to the code word length. This node allows you to choose a code rate of 1/2, 1/3, 1/4, 2/3, or 3/4, using the rate parameter. Use MT Convolutional Encoder (Generator Matrix) to set a custom value as the code rate.

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input bit stream

Bit sequence representing the data bits to encode. Use the bits generated by MT Generate Bits to produce this bit stream or wire a custom data bit stream to this parameter.

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rate

The convolutional code rate, which is a ratio of k/n, where k is the input data word length and n is the output code word length.

Name Description
1/2

Supports constraint lengths of 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17

1/3

Supports constraint lengths of 3,4,5,6,7,8,9,10,11,12,13,14

1/4

Supports constraint lengths of 3,4,5,6,7,8,9,10,11,12,13,14

2/3

Supports constraint lengths of 2,3,4,5,6

3/4

Supports constraint lengths of 2,3,4

Default: 1/2

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constraint length

The maximum number of encoded bits that can be affected by a single input bit. This value represents (1 + maximal memory order), where maximal memory order refers to the length of the longest shift register chain in the convolutional encoder.

Default: 3

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initial state

The encoder initialization state for the k(K-1) shift registers, where k is the input data word length and K specifies the constraint length. On the first call to this node, and thereafter when you configure reset? to TRUE, the encoder state is reset to this value on each call to this node. When you configure reset? to FALSE, the final state from the previous iteration is used in subsequent calls to this node and LabVIEW ignores the initial state parameter.

Default: 0

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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 internal state of the encoder is cleared.

TRUE Clears any buffered bits from previous iterations. Also initializes the encoder to start from the initial state parameter that you specify.
FALSE Continues encoding from the previous iteration. Any buffered bits from the previous iteration are added to the beginning of the input bit stream prior to encoding.

Default: TRUE

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output bit stream

Convolutional-encoded code word returned by this node. Wire this parameter to MT Convolutional Decode to recover the input data stream.

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final state

The value for the k(K-1) shift registers as the right-aligned (least significant) k(K-1) bits when this node completes execution, where K is the constraint length and k is the data word length in bits.

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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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