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CCS/TMS320C5505: Regarding generating the 40 kHz sine wave using TMS320c5505 EVM

Satyajit Chincholkar
Intellectual 495 points
Part Number: TMS320C5505

Tool/software: Code Composer Studio

Dear All,

Presently, I am working on the the project related to the implementation of parametric loudspeakers. In this project I want to generate the carrier signal of 40 KHz and modulate the audio signal onto this carrier. For this, I am using TMS320c5505 EVM and referring to the C5000 Teaching ROM available at http://processors.wiki.ti.com/index.php/Porting_C5000_Teaching_ROM_to_C5535_eZdsp . Regarding this, I have two doubts.

1) In chapter 4 of this CD-ROM, the code to generate the sinewave is given. However, using this code I can only generate the sinewave with frequency ~20 KHz. As I suggested earlier, I need to generate the sinewave with ~40 kHz. Can anyone please suggest me that how may I modify the code of chapter 4 to get the sinewave of ~40 kHz.

2) Also, how the sampling frequency can be increased to 192 Khz. I believe this is the maximum sampling frequency for TMS320c5505 EVM.

I would be really grateful if anyone could suggest me about this.

Thanks and regards,
Satyajit

  • 0
    TI__Guru 65405 points
    Hi Satyajit,

    I've forwarded this to the c55x software team. Their feedback should be posted here.

    BR
    Tsvetolin Shulev
  • 0
    TI__Mastermind 30365 points

    Satyajit,

    Have you tried to manipulate the various parameters in the main.c file as highlighted below to see if you can get the values you need?

    Lali

  • 0 in reply to Lalindra Jayatilleke
    Intellectual 495 points

    Dear Lalindra,

    First of all, many thanks for your prompt reply.

    Yes, I tried changing these parameters.

    For

    left_output = generate_sinewave(250,10000), 250 is the frequency in Hz and 10000 is the amplitude of sine wave.

    What I observed is maximum frequency of sine wave which can be generated using this code is around 20 KHz or may be slightly more than 20 KHz.

    If I used 40 kHz in code, the frequency of generated sinewave cannot go so high.

    I think there might be some problem in aic3204_init.c file in this project. 

    Please let me know if you could assist.

    Thanks and regards,

    Satyajit

  • 0 in reply to Satyajit Chincholkar
    TI__Mastermind 30365 points
    Satayajit,

    I don't know if the sampling rates and frequencies can go that high on the hardware.
    Aside of the teaching ROM, there are also some audio examples in the C55x CSL at C:\ti\c55_lp\c55_csl_3.07\ccs_v6.x_examples. Perhaps you may have some luck with those. I have looped in a colleague on this thread to add to the discussion if indeed there is something else.

    Lali