my question is about using Simulink. I was working on a project at school on Simulink and I used the Discrete Time VCO for QAM implementation on the school's computer. However, when I ran the same .mdl file from my computer, it showed a bad link on the VCO block. This VCO block was from the communication blockset of the Simulink library and I do not have this block in my Simulink library. Also, my version of MATLAB does not have the Communications Toolbox; my question is, if I purchase the Communications Toolbox from the mathworks website, will the communication blockset appear in my Simulink Library or can I upgrade the simulink and use this blockset instead of purchasing the toolbox for MATLAB? I mean do the toolboxes and blocksets work in harmony to run simulations? Thanks for your help.