How to set up a user defined bit sequence generator in OptiSystem. In this video we have a look at the bit sequence generator block in which the user can define the bit sequence that the block will output. This tutorial will cover the setup of the block as well as how to modify the block’s parameters.

About The Component

The user defined bit sequence block can be found under the folder path default/ transmitters library/ and bit sequence generator.

The user defined bit sequence generator can be used to generate a bit sequence that is user defined. The bit sequence generator can be connected to a binary sequence visualizer so that the output bit sequence can be seen. Double clicking the block shows the main properties. Double clicking beside bit rate we can change the bit rate of the block to base it on other parameters or to make it get it’s value from a function. Pressing Evaluate we can see what bit rate is currently defined as.  If we want to change the value of the bit rate defined for the entire project we can double click on our work space and the global parameters window will pop up. In the global parameters window the bit rate for the project as well as other global parameters may be changed. Now returning to the bit sequence generator and pressing evaluate script we can see that the bit rate has been updated. Before we test out the bit sequence generator, I am going to change the number of leading and trailing zeros so we can easily observe the output. Calculating the project and checking the visualizer, we can see that the bit sequence displayed is as expected. Going back into the bit sequence generator you can see that the bit sequence currently entered can be changed to whatever you wish it to be. We can also change the bit sequence definition to use a bit sequence that comes from a file. To do this change the bit sequence definition box from explicit sequence to file and then search for the data file that contains the bit sequence. On my screen you can see the file that contains the bit sequence. Upon calculating the project, we can see the bit sequence shown in the visualizer is the same bit sequence from the file. Going back to the bit sequence generator we can also change the bit sequence definition to be dependent on non-zero bits. To define which bits should be non-zero, we must enter the bit location of each non zero bit and separate each by a space. Running the program and clicking on the visualizer we can see the output sequence is as expected. One last thing we can do is is make the bit sequence repeat. Currently it is set to repeat every sequence length. The sequence length is defined by the global parameters and is currently set to 1024. As a demonstration I will change the repeat interval to repeat every 20 bits and test it out. Now we can Calculate the project and check the sequence out on the visualizer. As you can see the sequence starts to repeat after 20 bits as we expected.