Wave Source Component -- Proof of Concept Code

[RDunn]

This is a first pass at a component to read *.wav files. Works but not yet perfect.

The forum doesn’t allow attaching *.cpp and *.h (and *.qsch) files. So I appended “.txt” to the file names to work around this limitation.

This doesn’t work for *.qsch presumably due to some non-plaintext characters in the *.qsch file. The component/schematic is pretty simple to create – just a single output port named Out of type float (64-bit double). Looks like this:

Sample output from 1KHz sine sample file (which I also cannot upload).

Please let me know if you try it, have questions or improvements/corrections.
wavsrc.cpp.txt (14.1 KB)
WavSrc.h.txt (1.7 KB)

– robert

[EL34]

Hi, robert
I tried it and it works fine. Great job!

wave data = sin 1kHz + sin 1.1kHz

[Engelhardt]

I just added the ability to pass a string to a .DLL device. So you can pass a path to a .DLL, have it read the .wav file, and then play it into the simulation.

–Mike

[RDunn]

Thanks, Mike! I’ll update/check it out immediately.

–robert

[RDunn]

@Engelhardt

OK, uninstalled/reinstalled QSpice with reboots (just to reset things), downloaded and installed.

Generated a new component with an added attribute, “FileName”. Looks like this:

Tried that with & without quotes on the parameter.

Has the code generator been updated to generate string parms? All I see in the generated code is:
double &Out = data[0].d; // output

I expected another index, something like:
const char* Attr1 = data[1],str;

The netlist does contain the parameter (one of several variations):

      * C:\Dev\QSpice\Projects\WavSrc2\WavSrc.qsch
      ؆X1 «» «Vout´d» «»  WavSrc FileName="ABC"
      R1 Vout 0 1Meg
      .tran 150ms
      .end

I’ll mess around – it should be there as the next parameter. But let me know if I’m obviously on the wrong track.

Thanks!
–robert

[Engelhardt]

Instead of

FileName=“ABC”

use

char *filename=“abc”

not that case makes a difference.

For more options passing parameters to the .DLL, point at symbol and press “F1”

–Mike

[RDunn]

@Engelhardt

Well, I thought that I tried that yesterday. Anyway, updated QSpice and it works today. Excellent.

I was going to mention making it const but I see that you’re way ahead of me.

Thanks.

–robert

[RDunn]

@Engelhardt

OK, I decided to add a second attribute. The auto-generate doesn’t include the additional value in the code. It is present in the netlist.

FWIW, I also tried bool loop=false & bool loop=0. Those also didn’t get included in the code although present in the netlist. Also tried exiting/restarting QSpice. No joy.

Thanks.

–robert

[Engelhardt]

Oh, it was only working if the char * parameter was the last attribute. But I changed it as of the current update so that you can put “int loop=1 bool done=false” after the char * parameter.

But you will have to regenerate the C++ template with the right click C++ => Create C++ Template command.

–Mike

[RDunn]

@Engelhardt

Thanks. Working on the project now so I’ll update and see how it goes.

–robert

[RDunn]

@Engelhardt

Looks like the code generation issue is fixed. Will roll it into my code and let you know if there are more problems. I don’t expect any.

While it’s not your issue to solve or a proper topic for this thread, the QSpice update process is horribly broken. I’ll post about that separately. Just had to vent.

Thanks for all of your prompt help!

–robert

[RDunn]

OK, I think that I have the WavSrc component functionally complete. Here’s what it does:

• Reads a *.wav file with single or dual channels. Currently only basic 16-bit PCM-encoded files are supported. (Probably won’t add more formats.) If only one channel is present, it simply duplicates the data on the second output.

• File is specified with an attribute. Seems to honor path bits properly.

• Has a gain attribute to apply to the nominal 1.0Vp input values.

• Has a Vref input which is sets the 0V reference. It could be a DC offset or , in theory, be used to modulate the wav outputs.

• Has a loops attribute to specify how many times the input file is read/processed,

Here’s a sample setup:

V1 is for comparison against a sample wav file:

And zoomed:

WavSrc CH1 tracks Vsin quite nicely with, of course, digital sample stepping.

Need to do a bit more cleanup before sharing but that’s the preview.

If anyone thinks of something else to add, please let me know.

–robert

[lpoma]

Hi,

Thank you for this POC component!

I’m running into a strange issue. I generated a very simple .wav file. (1KHz for 100ms at 1Vpp).
However, if a place a 1 ohm resistor to GND on the output, the output Voltage is 1mVpp.
If I change the resistor to GND to 1Gohms. I get the 1Vpp of the .wav file.
I’m getting use to the C++ interface and your original .cpp code. However, I hadn’t detected the effect of a series resistance in your code.

Len

UPDATE!!!

I just found the ROUT=1000 ohm default output setting in the Symbol Text help info. Once I change ROUT = 1f, I get my expected 1Vpp results.

[lpoma]

Robert,

Do you have updated .cpp file to achieve the extra input parameters such is filenames, loop, etc?

Len

[RDunn]

@lpoma

I do but haven’t posted it yet. Probably later today.

–robert

[RDunn]

OK, here are the current Proof of Concept WAV code and sample files: GitHub - robdunn4/QSpice-WavSrc: QSpice schematics, symbols, code, tools, etc.. There’s no “user documentation” yet – just the C-Block code and schematic and some test WAV files.

Note that, after I learn a bit more about GitHub, I’ll likely move the project to a different repository with better organization. In other words, the link won’t likely be active forever…

Let me know what works, doesn’t work, etc. TIA.

Edit: I’m struggling with trying to get the code rolled into a symbol. Seems like it should be simple but passing in parameters (i.e., filename, loops, gain) from the symbol dropped into a schematic to the underlying stuff is eluding me. Feel free to beat me to that, share, and be my hero.

–robert

[carlvanwormer]

Are you planning to create the compliment feature, outputting a WAV file from a QSPICE signal? I used that feature in LTspice to simulate the stereo output of the ShortSniffer during the development phase. The hardware prototype performed in a similar fashion, sounding just like the simulation!

[RDunn]

I’ve thought about it but no current plans. The basic structure of the code could be adapted to write instead of read… Care to give it a try?

–robert

[carlvanwormer]

I looked at the C++ code and realized that I’m not the guy to do the job. I’m an Analog Guy with minimal code hacking abilities (BASIC and assembly from TRS-80 and early PCs). Maybe somebody else will get excited about the challenge . . .
Thanks for what you are doing.
Carl

[RDunn]

Hi, Carlvanwormer. See WavIO Components for QSpice (*.wav files) for new code.

–robert