Need help with A/D-D/A project

[manotronic]

I have to solve this problem: There is a microphone. I talk to it and the analog signal is converted to a digital word (e.g 8 LEDS) with an A/D converter. Then this digital signal is converted again into an analog signal
(voltage).This voltage is being amplified and finally we should be able to hear the initial signal(voice) coming out of speaker.
I would be grateful if anyone told me how can i do this.If you can,send as an answer an apropriate website that deals with similar projects.
Thanx a lot.(sorry for any mistakes in the syntax)

 

[kinjalgp]

Why do you want to convert audio signal into digital and back to analog when you can directly couple to your speaker through analog amplifier. If there is memory in between for audio storage then it makes some sense. But doing it for real time purpose would be useless.

 

[Scubasteve]

Hey,

You should show us your application in more depth so we can make better suggestions. For practical purposes, it is best to use a dedicated codec for en/decoding the audio. You need to worry about powering the microphone, impedance matching, noise, sample rates, clock synchronisation and other issues.

Steve

 

[manotronic]

"Why do you want to convert audio signal into digital and back to analog"

In fact, my professor in the university,told us to accomplish tis projekt so that we can be able to give exams for his lesson.

"You should show us your application in more depth"

I don't have more details...My professor said:This is the topic,you are free to make it as you wish.We cover 15$.
As you understand he didn't give us anything else to start.The problem is
i am not experienced with such practical problems,so i would be very glad
if you recommended me a web-page with a similar problem.

 

[Scubasteve]

Okay then..

You need to find a microphone.. Electret is the best to use.. Follow the recommended power and pinout. You need to try to match the impedance of the microphone to the analog input on a A/D converter IC. Then you supply a clock signal at a high rate (make it variable for experimentation), which will also go to your D/A converter. Then you get a D/A converter and feed the output to a small audio amplifier.

That is the basic system, which you should be able to find information on through a search. I think many of the people here and I will agree on the morality of a student figuring out their own assignments, it will make you learn in the long run. Guidance is one thing, but doing everything bit for bit is another..

Good luck!,

Steve