PWM for generating sound ??

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drdigital

Joined: 13 Apr 2009
Posts: 28

19 Apr 2009 23:50 pwm sound

Hi All,
I'm on my way to make an audio player.
My platform is 8051 but i think it will not fit my requirements for RAM buffers or integrated required peripherals so I could move to AVR. I have no experience about PWM so I'm asking about somt things ...

1- Is it different from Using DACs ? which one is better in generating a good quality sound?
2- any suggestions for good materials to start learning about PWM and understand it well ? or can any one talk simply about it ?

3-which platforms will be more suitable in my audio player application (8051 or AVR ) ( DAC or PWM) what type of DACs is suitable if you suggest it and what resolution will be enought in PWM case and what's the version of uC that meet these needs ?

I want to play songs in a nice quality ... that's all what I need .. what ever the extension of the file was or the modulation or sampling rate .

Thanks in advance.

srikanthsamaga

Joined: 14 Dec 2008
Posts: 101
Helped: 4
Location: Mangalore

20 Apr 2009 3:01 avr pwm sound

drdigital wrote:

1- Is it different from Using DACs ? which one is better in generating a good quality sound?
2- any suggestions for good materials to start learning about PWM and understand it well ? or can any one talk simply about it ?

3-which platforms will be more suitable in my audio player application (8051 or AVR ) ( DAC or PWM) what type of DACs is suitable if you suggest it and what resolution will be enought in PWM case and what's the version of uC that meet these needs ?

1.they are different..
Obviously DAC is better for good quality audio....

2.Google is your friend. You will gets lots of info about PWM. PWM is simply varying width of a pulse.
You can get info on PWM using 8051 at:
http://www.shree-electronics.com/pwm.htm

3.AVR is a better choice, If you are a 8051 guru, then use 8051 itself..

Very Happy

drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 7:50 avr pwm audio

Thanks for your replay:
still want a detailed answer of this question :
3-which platforms will be more suitable in my audio player application (8051 or AVR ) ( DAC or PWM) what type of DACs is suitable if you suggest it and what resolution will be enough in PWM case and what's the version of uC that meet these needs ?

srikanthsamaga

Joined: 14 Dec 2008
Posts: 101
Helped: 4
Location: Mangalore

20 Apr 2009 13:57 sound pwm

If you are a newbie for microcontrollers, then you may choose AVR for your application, because you need a high speed mcu, also you cannot optimise your program in 8051 to be fast since you are a newbie..
And DAC is better than PWM for audio applications..
Since I haven't used DAC, I can't help you in choosing DAC. I think a 8 bit or 10 bit DAC can do your job..

drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 14:23 generating sound using pwm

Thanks, But is the 8-bit DAC suitable for generating a high quality sounds like wav or mp3 files ?

and Can I know why it is better ?

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GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

20 Apr 2009 14:33 play sound using pwm

You don't say much about your project, but have you considered using a CODEC like the VS100x family - http://www.vlsi.fi/. These chips do all of the stream to audio conversion for you. There are several products that support a variety of formats - MP3, WMA, WAV, IMA ADPCM, MIDI, Ogg Vorbis, AAC.

Depending on what your needs are, you may not need a uP.

drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 14:37 avr pwm dac audio

I know a bout this chips , but I plan to make a .wav player without one of these chips, Can't I ?.
by simply reading the wav file data and (PLAY IT).

Now I want to Know how to play it. I want the details to start .

Thanks for your replay Smile

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

20 Apr 2009 15:07 create sound using pwm

Sure you can use a uP and a DAC to produce good quality audio. A few years ago I designed an OEM iPod interface for automobiles that output audio for navigating through the menus (using WAV files). It was based on an 8-bit PIC proceesor with an R2R ladder network as the DAC.

What hardware you need will depend on the frequency you want to output at. Below 16KHz you can do mono output with an 8-bit uP assuming it's not doing a lot of other stuff. At frequencies above that you'll need a faster processor. Microchip has some app notes and code on their web site - just go to www.Microchip.com and search for "WAV".

drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 15:17 pic play wav pwm 10bit

will the 8-bit DAC be sufficient for producing good quality ?
do you have any example of what the output may look like ?

Thanks So much for your help