Help: Staircase Waveform file needed!

[truzz]

Hi folks,

I searched online, no luck.
Probably some of you owning an arbitrary waveform generator may help.

I need a .wav mono file of an up-going 7-step staircase wave form
step period should be 10mS,
total level 0dBFS

If anyone can help that would be fantastic!

Thanks in advance.

 

[JohnRoberts]

I can imagine a circuit using CMOS logic and an opamp, but may be more effort than you have in mind.

I could also program a microprocessor to make that.. also too much work.

With that timing are you talking about a DC coupled path?

JR

 

[truzz]

John, thank you for taking the time to reply.

Yes, DC coupled,
I had in mind to sync it with a 100Hz sawtooth for curve tracing some small signal mosfets
from my audio card to a scope, without too much pain.

 

[JohnRoberts]

OK look at CMOS logic I don't recall the actual part number but something like a multistage shift register. You clock the SR with your 100Hz and it shifts the high pulse one position per clock. If you can't fing a multi stage you can run several short SR in series.

You can weigh resistor values from subsequent outputs  R for 1st output, r/2 for 2nd, r/3 for 3rd, r/4 for 4th, r/5 for 5th, etc.

The easy way using two opamps one to invert the output to a positive staircase, and onther to level shift.

There may be a simpler way using just resistors and instead of pushing a single step through the SR, lift the outputs one at a time until all 7 are high. You can use the 8th output to reset the whole thing. 

or not...

The CD4000 series of CMOS was fun for oddball circuits like this...

I won't deprive you of the fun of working out the details.

JR

 

[truzz]

LOL
yes, that would be fun.
An Italian magazine had a kit available in the '80s, the heart of it was the 12-stage ripple carry binary counter
CD4040, with 2 TDA2030 both on current generator of stair and sawtooth.
Unfortunately the kit is not available anymore.
Similar circuitry pops up on eBay, very cheap.

Anyway, my original idea was not on building parts,
just play the 2 audio wav files on my pro tools,
a source and a drain resistor, all sent to the scope.
As simple as this.

I think Matlab and similar software may generate this wav file (I'm not sure),
but not being a programmer, I wouldn't know how to do it.

Any hints?

TIA

 

[culteousness1]

I think Matlab and similar software may generate this wav file (I'm not sure),
but not being a programmer, I wouldn't know how to do it.

Any hints?

TIA

I am not sure, if you can access MATLAB.
But the built-in

wavwrite()

should do the job.
Just type

doc wavwrite

into the console.

Furthermore, you should specify the desired
step potential (dB).

Best,
Carsten

 

[iyahdub]

What is it the use of it for?! Total level 0dbfs but what DAC are you using?! Whats its dynamic range?! You need it with dc offset or not ? Or is it for a wave player? If so, what bitrate?!You were a bit vague there. Im sure its easy to code such a simple one like that in c or similar !
If you get more details i might be able to help you...

 

[zebra50]

>Furthermore, you should specify the desired  step potential (dB).

If so, it might well be possible in protools, using the signal generator to spit out a square wave, and then automating the amplitude in 10 ms steps. Maybe.

 

[audiomixer]

I'am a bit puzzled... I don't think your soundcard will output dc level at all...??? your chart reads DC at least. now you could rectify your soundcard output to dc and possibly so with great precision, but that doesn't require a stepped waveform, rather a set of sines with different amplitude. use whatever frequency generator and change level as required.. when rectified properly with a opamp circuit this will look like what you are searching.

I might not fully undestand your initial request, so disregard if I am totally off topic ;-)

- michael

 

[truzz]

>Furthermore, you should specify the desired  step potential (dB).

If so, it might well be possible in protools, using the signal generator to spit out a square wave, and then automating the amplitude in 10 ms steps. Maybe.

You had a good idea. That worked best for me.
I did it with the consolidate region feature.
It has been very time consuming, but I did it at last.

[quote author=audiomixer]
I'am a bit puzzled... I don't think your soundcard will output dc level at all...[/quote]

to clarify: I needed a 12Vp-p starting from negative, crossing through zero at the central step, and full positive, then
immediately return to full negative and start the cycle again.
I did it in pro tools, checked with a DC coupled scope, and the waveform is exactly the way I needed.

Thank you !!!!

 

[iyahdub]

...to clarify: I needed a 12Vp-p ...

I have to ask this : 12 V p-p wav file ? 12 V?
Where you gonna play that ?!