Help! About Spectrum Analyzer based on the sound card of PC.

[Lab]

I couldn't get the real thd value of 20Hz sine wave by my program,

How can I get a good 20Hz sine wave by the sound card?Adjust

its sampling rate?

The attached file is the parf of my program.

[qqtang]

you should use filter to denoise or replace a good sound card.

[Clipper]

Folks,

I see you made a application like mine in but C. Cool.

Still, I thought you may be able to help. I am a LabVIEW convert since 1995, but I suck at C.

Using LV2009 I made a decent do-it-myself sound card spectrum analyzer starting with a sound example vi.

Unfortunately it would not compile/build -- "Error 6" whatever that means.

(After all these years I just started using the app builder.)

Please help.

I want to share it with my EE buddies; here it is for you, too, attached.

--Peter

Also attached  is the crypto code from the builder/compiler.