digital voice recorder

my project includes sampling the voice using ADC and storing the data in flash memory and finally retreiving it from memory using DAC. The platform being 89c51 microcontroller

1.) i've made a basic preamplifier and checked it's o/p on CRO and it's amplitude is limited to 1V. I want to know whether my ADC could sample such variations.

2.) Please tell me some power amplifier configuration
(if possibly LM 386)to test the o/p of this circuit , by connecting it at o/p of this circuit,without connecting it to microcontroller.


thanks

schematic

my circuit is not attached as attachment. Kindly help.[/img]

piyush_it1 said:

1.) i've made a basic preamplifier and checked it's o/p on CRO and it's amplitude is limited to 1V. I want to know whether my ADC could sample such variations.

Click to expand...

most of the ADC i/p varies from 0-5V for FSD , so u have to amplify the signal 5 times to get the full resolution of the adc.

2.) Please tell me some power amplifier configuration
(if possibly LM 386)to test the o/p of this circuit , by connecting it at o/p of this circuit,without connecting it to microcontroller.

Click to expand...

u can find sample design of poweramp in the datasheet of lm386

A couple of points for digitising audio:

1) You MUST have a low pass filter on the input, with a fairly sharp cutoff no higher than half the sampling rate, and preferably lower than than.

2) You MUST make 100% sure that you NEVER clip the input to the DAC, this produces incredibly bad distortion

Nigel Goodwin said:

A couple of points for digitising audio:

1) You MUST have a low pass filter on the input, with a fairly sharp cutoff no higher than half the sampling rate, and preferably lower than than.

2) You MUST make 100% sure that you NEVER clip the input to the DAC, this produces incredibly bad distortion

Click to expand...

ADC ??

akg said:

Nigel Goodwin said:

A couple of points for digitising audio:

1) You MUST have a low pass filter on the input, with a fairly sharp cutoff no higher than half the sampling rate, and preferably lower than than.

2) You MUST make 100% sure that you NEVER clip the input to the DAC, this produces incredibly bad distortion

Click to expand...

ADC ??

Click to expand...

Yes! - sorry