Thread: Input Bandwidth of an ADC.
View Single Post
  #2   Report Post  
Old September 28th 06, 09:42 PM posted to rec.radio.amateur.homebrew
Ben Jackson Ben Jackson is offline
external usenet poster
  
First recorded activity by RadioBanter: Jun 2006
Posts: 34
Default Input Bandwidth of an ADC.
On 2006-09-28, wrote:

I am not sure why is this input bandwidth different from Fs/2.

It's really two different bandwidths. Fs is determined by the bandwidth
of the signal. If you filter a 10MHz passband from a 1GHz signal, your
Fs calculation is based on the 10MHz of signal (if you choose to
undersample, which would clearly be to your advantage in a case like
this). However, since it's up at 1GHz, even though you might be able
to use a Fs 20MHz, the ADC must have a sample and hold
bandwidth 2GSps.

If your input signal has components from DC up to your desired signal,
then the two bandwidths are the same.

--
Ben Jackson AD7GD

http://www.ben.com/
Reply With QuoteReply With Quote