现在想用1452输出20khz以上的正弦波，比如40khz或者60khz。目前调节了sampling rate之后，仍然无法达到想要的正弦频率，而且本身的正弦波控件频率也改变了，比如我设置fs为48k，正弦波控件设置1khz，输出为1khz。而fs提升到96khz后，输出变为500hz。当提升为384k后，全部都跑偏了，这个怎么处理？

Hello tear,

Have a look at this post:

(+) If channging the samping frequency all fiter values are wrong. Did I miss a parameter ? - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone (analog.com)

Dave T

thank you.

how can i get a 40k sin wave output?now i can only get 20k.

Hello tear,

What eval board are you using? You can send a picture might help.

If it is your board or some other board, then tell me what the master clock frequency is on the PCB? How is the Codec clocked? Where is the master clock for the codec coming from?

Can you attach your project?

A schematic of the hardware would be helpful. 

Dave T

thank you very much.

my codec is AD1938YSTZRL,the codec main clk is come from the ADAU1452,

the osc is using 12.288Mhz.(ADAU1452 using this,than clk output for ad1938)

my project clk is like the pic.

If your leave an email, I can send you the project i'm using now.

thank you agian and agian

Hello tear,

Thank you for the additional information. I assume the CLKOUT of the DSP is going to the MCLK_IN of the codec correct? This is good and you have the CLKOUT set correctly to 12.288MHz. 

While I am still talking about the DSP. You have the SigmaStudio sampling rate set correctly so it will produce code written for 192kHz fs. 

You have the DSP Start Pulse set correctly to 192kHz so the core is running at 192kHz so that is good. What is not good is the serial port is set to FS. 

Set the serial port sampling rate to 4*fs so it will be sending out clocks at 192kHz. 

Now I will move over to the Codec. 

Thank you for the schematic. The codec is setup to operate in StandAlone mode. In this mode it will only operate at an fs=48kHz with a MCLK of 12.288MHz. 

You will have to change the hardware to allow the codec to be controlled by some other device so that the codec can be setup to operate at 192kHz. 

Do you have a controller in the system?

Dave T