C28x Signal Gen Offset parameter

TobyM

Genius 5200 points

Hi folks

is there any further info on the offset parameter for the SGENT modules of the signal generator library?

For e.g. is the offset added to the output value? multiplied by it? Is the parameter range 0-1 (as it appears to be)?

Basically the only info on this provided by the user manual is "offset - DC offset in the SIN signal - Q15 - 0-7FFF"

over 13 years ago

0 Brett Larimore over 13 years ago

TI__Guru 57255 points

Toby,

The offset is added to the output value after gain is multiplied in. The hint for this in the comments of the sgt1c.asm file.

The range would technically be -0.5 to 0.5 in Q15. (the equivalent 8000-7FFF (Q0) is presented in the docs)

I'm looking at v101 of the library.

Thank you,
Brett

0 TobyM over 13 years ago in reply to Brett Larimore

Genius 5200 points

Hi Brett

Thanks for your reply

Just to clarify, to set the offset would the following C be sufficient?

sgen.gain = _IQ15(-0.2);

Thanks

0 Brett Larimore over 13 years ago in reply to TobyM

TI__Guru 57255 points

Toby,

(I assume that the statement should be sgen.offset = _IQ15(-0.2))

I believe so. You could always set a breakpoint after this statement to make sure.

Thank you,
Brett

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C28x Signal Gen Offset parameter