Forums

oversampling

Started by CW May 22, 2009
Assume i receive a signal and perform direct conversion from passband
to baseband with a front end analog filter with bandwidth +/- B for my
signal.  In my ADC I sample at 2B and have a signal plus noise limited
to the band +/-B with each noise sample assumed to be uncorrelated.
If i instead decide to sample the signal at the output of the analog
filter at 10B i will have correlated noise on the samples.

Does this mean that if i have a simulation with oversampling greater
than 2B, i have to add non-white noise prior to performing any signal
processing on the samples?

CW
On Fri, 22 May 2009 07:03:53 -0700, CW wrote:

> Assume i receive a signal and perform direct conversion from passband to > baseband with a front end analog filter with bandwidth +/- B for my > signal.
This must be homework, because only in a homework problem or a classroom do you encounter a perfectly bandlimited signal. They simply don't occur in nature (feel free to explain why).
> In my ADC I sample at 2B and have a signal plus noise limited > to the band +/-B with each noise sample assumed to be uncorrelated. If i > instead decide to sample the signal at the output of the analog filter > at 10B i will have correlated noise on the samples.
Will you? Where is the noise coming from? Will _all_ the noise in a _real_ system come from _just_ the sources that are spelled out in a homework assignment?
> Does this mean that if i have a simulation with oversampling greater > than 2B, i have to add non-white noise prior to performing any signal > processing on the samples?
Maybe. What are you simulating? -- www.wescottdesign.com