Exceeding capabilities of ADAU1781

Hi there,

 

I am trying to implement DSP schematic with a 9 band double precision optimized EQ.  However, whenever I go beyond 7 bands, I observe a distorted output. 

 

I was wondering if there is a way to identify whether I have exceed the processing capabilities with Sigma Studio.  Based on the output, from the compiler, it appears fine.  However, the resulting audio output is distorted.

 

Sigma Studio Version 3.9. Build 2, Rev 1220

 

 

Analog Devices Compiler for the 3rd generation SigmaDSP core.

Build date = 7/24/2013 at 10:32 PM

 

 

## Summary ##

(Note: Estimates are based on a 48 kHz sample rate)

 

 

Instructions used:

447          (out of a possible 512 )

Modulo Data RAM used (X Memory):

226          (out of a possible 512 )

Non Modulo Data RAM used (X Memory):

2          (out of a possible 512 )

Parameter RAM used (Y Memory):

157          (out of a possible 512 )

 

 

Instance                                          Mips          Inst          Data          Coeff          Other

                                                            (max)

SPhat1                                            162          162          90          52

Automatic Volume Control1                         123          123          56          49

Stereo Switch                                     69          69          22          1

Mid EQ1                                           17          17          50          39          using:          Biquad Looping SP

Beginning                                         17          17          0          1

SafeLoadCode                                      15          15          0          7

LPF                                               10          10          7          8          using:          Biquad Looping SP

End                                               6          6          0          0

Input1                                            4          4          2          0

Add1                                              3          3          1          0

Output4                                           2          2          0          0

Output1                                           2          2          0          0

Output2                                           2          2          0          0

Output3                                           2          2          0          0

 

 

Subroutines called:

* Biquad Looping SP                               111          13          0          0

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

Total                                                    545          447          228          157

----------------------------------------------------------------------------------------------------------------------------------------------------------------------

(%)                                                        53%          87%          45%          31%

 

 

Files written: 

program_data.dat - load file for downloading code using ADI loader

hex_program_data.dat - load file for downloading code using microcontroller

ParamAddress.dat - Parameter RAM locations for schematic instances

  • 0
    •  Analog Employees 
    on May 9, 2014 8:58 PM

    Hi Rocky:

    It doesn't seem like you are exceeding the capabilities of the 1781. I'm not sure how much the datasheet shows but there are 2 limits that you must take into account in relationship to the programs to execute on the 1781. The first one is related to not exceeding the number of instructions to use (<512), the other is to not exceed the number of MIPS to use (<1024). If you are running however at a hight sampling rate (say 96kHz) then the MIPS limits gets reduced by half. To use more MIPS than instructions, you should do what you are already doing, (using algorithms that contain subroutins within).

    Could you share your project?

    Also, can you comment on the FS you are using?

    Thank you

    Miguel

  • Thanks Miguel,

    Thank you for the clarification.  I was under the impression that that was the case.  However, I was seeing artifacts in the output that would indicate some issues.

    As for the project, I can send you the project via email.

    The FS that I am using is 48kHz

    -Rocky

  • 0
    •  Analog Employees 
    on Aug 2, 2018 2:39 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin