arduino mega 2560 samples per second

Hi,

does any one knows how much samples arduino mega 2560 takes per second ?
whats the rate?

thank you

Analogue or digital?

both.
and can you help me how the sampling on digital output works ?

Out-of-the box analogue, around 9000 samples per second.
Digital? Depends on how you sample (parallel or bitwise), and what you do with it.

What are you trying to do?

Basically I am planning to feed it 2-3 analog signals, do the sorting and get 2-3 digital out put and storing that data on a SD card

Basically I am planning to feed it 2-3 analog signals

There's only one ADC, so sharing it three ways reduces your per-channel sample rate to around 3000 samples per second, so a bandwidth of 1500Hz.
That's pretty poor quality, around half the bandwidth of a standard speech channel.

You can increase the rate, at the expense of resolution.

can you please explain what do you mean by ' expense of resolution '?
and what about the digital output rate ?

By default, analogRead returns 10 bit samples.
If you can accept eight bit samples, your can increase the sample rate.

and what about the digital output ?

Depends on how much processing you're doing.