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Last Modified: February 7, 2018

Performs interleaving using a fixed number of branches and a fixed unit delay.

Each branch has different delays associated with it. Hence, the data input of each interleaver branch is delayed by a specific amount (the amount of delay in that branch) before the interleaver returns the data. A convolutional interleaver is twice as efficient as a block interleaver.

The input data to the interleaver.

The number of branches of the convolutional interleaver. Data elements pass through the branches in a cyclic fashion. For example, in an *N* branch convolutional interleaver, data element 0 goes through branch 0, element 1 goes through branch 1, element *N*-1 goes through branch *N*-1, element *N* returns through branch 0, and so on. Each branch incorporates different delays.

**Default: **0

The unit delay value. If this value is defined as *D*, then the number of delays on the *i*th branch is (*i*×*D*). If the total number of branches is *N*, then *i* = 0, 1,…, *N*-1.

**Default: **0

The shift register values when the convolutional interleaver begins operation.

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

The convolutional interleaved data returned by this node.

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.

The following example demonstrates convolutional interleaving and deinterleaving. Let the **data in** be: x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, …

Interleaver Input Interleaver Output

D = unit delay in the path.

Assume for this example that the unit delay = 1, and the initial state shift registers are initialized with values of 0 for both the interleaver and the deinterleaver.

Interleaved Data: x0, 0, 0, 0, x4, x1, 0, 0, x8, x5, x2, 0, x12, x9, …

Deinterleaver Input Deinterleaver Output

Deinterleaved Data: 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, …

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: Not supported

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