GENGOLD

Scicos Block
fr - eng

Gold sequence generator block

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Gold sequence generator block

Gold sequence generator is a class of pseudorandom generator which has good randomness properties to decrease the multiple access noise found in multi-user DS-CDMA communication systems. It is composed with two Maximal Length Liner Shift Register (MLLSR) sequence generator. Most properties of this registers can be found in [1]. An example of block diagram of Gold sequence generator with 5-length MLLSR is shown in Fig. 1.

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Figure 1: Gold sequence generator

Each clock time, the registers shift all elements to the right. The following general equation gives the output of a Gold generator:

$\begin{eqnarray} c_{n}&=&{\displaystyle \sum_{i=1}^{r}Ca_{i}a_{n-i}+\sum_{i=1}^{r}Cb_{i}b_{n-i}}. \end{eqnarray}$

$a_{n}$ and $b_{n}$ are the outputs of the MLLRS, $Ca_{i}$ and $Cb_{i}$ are the corresponding connection variables and

the length of registers. All terms are binary, meaning that adders are realized with the boolean exclusive-OR operator. In fact, each register needs only two integer value to be processed (one value for states and one value for connections). In that block, all operations -modulo-2 adders, shifts- are realized with the binary operators of C language that ensures fast dynamical computation.

Dialog box

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Vector of Size of outputs
Type 'vec' of size -1. The length of sequences.
Vector of Length of register
Type 'vec' of size -1. The length of register(s).
Vector of Initial condition register 1
Type 'vec' of size -1. The initial state of register(s) 1 in integer value.
Vector of Initial condition register 2
Type 'vec' of size -1. The initial state of register(s) 2 in integer value.
Vector of coefficients register 1
Type 'vec' of size -1. The coefficients of register(s) 1 in integer value.
Vector of coefficients register 2
Type 'vec' of size -1. The coefficients of register(s) 1 in integer value.
Initial Delay
Type 'vec' of size 1. The initial delay in sample.