Communications Blockset

Descrambler

Descramble the input signal

Library

Sequence Operations, in Basic Comm Functions

Description

The Descrambler block descrambles the scalar input signal. The Descrambler block is the inverse of the Scrambler block. If you use the Scrambler block in the transmitter, then you should use the Descrambler block in the receiver.

Below is a schematic of the descrambler. All adders perform addition modulo N, where N is the Calculation base parameter. The input values must be integers between 0 and N-1.

At each time step, the input causes the contents of the registers to shift sequentially. Each switch in the descrambler is on or off as defined by the Scramble polynomial parameter. To make the Descrambler block reverse the operation of the Scrambler block, use the same Scramble polynomial parameters in both blocks. The Initial states can be different in the two blocks, considering the transmitting and receiving filter delay. See the reference page for the Scrambler block for more information about these parameters.

Dialog Box

Calculation base

The calculation base N. The input and output of this block are integers in the range [0, N-1].

Scramble polynomial

A polynomial that defines the connections in the scrambler.

Initial states

The states of the scrambler's registers when the simulation starts.

Pair Block

Scrambler

Derepeat

Differential Decoder