In Simulink ,the pn sequence generator(essential blk) in frame based mode s not being accepted by the hdl converter. But the output of the pn sequence generator is given to a serial to parallel converter. What cud b the alternative for this?

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Answer 1

[Bharath Venkataraman]

Please check to see if the inputs are constants. If so, change the sample time on the constant block to be 1 or some such value.

One other thing you can do for your initial question is to get values to the PN sequence genrator serially, and take the output to a tap delay line from which you can get a list of multiple values. To ensure you get non-repeated values, you can use a downsample block right after the tap delay. Putting a uni delay block after the downsample genrates more efficient HDL code.

For a set of 10 values, PN Sequence (serial) -> Tap Delay (10) -> Downsample (10) -> Unit Delay

Answer 2

[Tim McBrayer]

Frame based models are not supported by HDL Coder. You will need to convert your design to a sample based format. Frames can exist outside the portion of design being converted to HDL code, if necessary.

[sin]

so instead of an inbuilt psuedorandom generator, we used a matlab function block. An error msg saying "system objects cannot be supported when the inputs have constant sample time" popped up while trying to convert the simulink to hdl. What does that error mean?

Answer 3

[sin]

Hey thanks for the reply, but if we connect pn sequence to tap delay-> downsample->unit delay as u said all the outputs appear 0. And using matlab function block instead of pnseq block generates error such as" unsupported system objects" or " cannot use system objects when all the inputs have constant sample time". These errors appear during hdl conversion.

Thnaks in Advance

Answer 4

[sin]

Pls help . its urgent some unsupported loop problem in matlab function block in simulink. even though the output of the previous block displays only single vector of output, the matlab function displays more than one input vector. coz of this , its not getting converted using hdl converter. it would be great if some one can help.

thanks in advance

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency