ASK modulator

[EngIntoHW]

Could someone please explain what is the last block for in the below block diagram of ASK modulator?

**broken link removed**

 

[EngIntoHW]

Anyone please?

 

[BrownOut]

It looks like a mistake. It says A/D, but I think it's an digital to analog converter.

 

[EngIntoHW]

The channel's output must be analog, and the receiver's filter - Hr(f) - can't turn an analog signal into digital, so I believe the converter is indeed analog to digital.

 

[EngIntoHW]

Someone knows?

 

[mbarazeen]

may be amplitude decoder?

 

[EngIntoHW]

Doesn't the ADC already perform as some kind of an amplitude decoder?

 

[Reloadron]

This link explains in some detail ASK (Amplitude Shift Keying) and will likely make your head hurt. The last stage is an A/D converter that outputs the binary sequence. A Google of Amplitude Shift Keying should bring up more information.

Ron

 

[BrownOut]

The last stage is an A/D converter that outputs the binary sequence.

Ron

Ok, I got fooled by the 4-ary signal representation, which I interpreted as a quantized analog signal.

 

[Reloadron]

Ok, I got fooled by the 4-ary signal representation, which I interpreted as a quantized analog signal.

I read it, then read it again. Then took two aspirin and opened a beer. I think in the original drawing it is a little misleading as the final signal looks to be the output of a D/A right down to the step increments. That was my take anyway, then came Google.

Ron

 

[EngIntoHW]

Hi Ron.

Thanks for the help.

The PDF you attached here has no info about this last block in the diagram.
The PDF shows nothing after the ADC.

 

[Reloadron]

I believe the last block in your drawing represents the A/D output sequence. I am not sure because of the way it is drawn. This isn't quite my forte.

Ron

 

[EngIntoHW]

Got it,
Thanks Ron

 

[BrownOut]

The last block is an ADC. The drawing shows that output is a 4-ary value.

 

[EngIntoHW]

Oh, I see now!

Thanks!