matlab modem.oqpskmod

I wanted to use the following (in MATLAB R2007a)

        h = modem.oqpskmod

but MATLAB complains that modem is not defined as follows:

??? Undefined function or variable 'modem'.

Error in ==> p开发者_运维问答rogram at 34
h = modem.oqpskmod

Is there anything i will have to include, import,... in order to be able to use modem.oqpskmod? thanks!

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Modem objects were first introduced in Version 4.0 (R2007b) of the Communications Toolbox, and they are now a class in the newer versions (with oqpskmod being a method of that class, hence the syntax modem.oqpskmod). Since you are using MATLAB Version 7.4 (R2007a), I'm guessing you are also using Version 3.5 of the Communications Toolbox (the version just before modem objects were introduced). This would explain why MATLAB is saying that modem is undefined.

You can check which version of the Communications Toolbox you are using with the VER function. Just type ver at the command prompt to see a list of the versions of all the installed toolboxes.