PlanetMath (more info)
 Math for the people, by the people.
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
Owner confidence rating: High Entry average rating: Very high
sampling theorem (Theorem)

Sampling Theorem

The greyvalues of digitized one- or two-dimensional signals are typically generated by an analogue-to-digital converter (ADC), by sampling a continuous signal at fixed intervals (e.g. in time), and quantizing (digitizing) the samples. The sampling (or point sampling) theorem states that a band-limited analogue signal $ x_a(t)$, i.e. a signal in a finite frequency band (e.g. between 0 and BHz), can be completely reconstructed from its samples $ x(n) = x(nT)$, if the sampling frequency is greater than $ 2B$ (the Nyquist rate); expressed in the time domain, this means that the sampling interval $ T$ is at most $ \frac{1}{2B}$ seconds. Undersampling can produce serious errors (aliasing) by introducing artifacts of low frequencies, both in one-dimensional signals and in digital images.

\includegraphics[scale=.5]{img988.eps}

References



"sampling theorem" is owned by akrowne.
(view preamble | get metadata)

View style:

Other names:  Nyquist's theorem

Attachments:
proof of sampling theorem (Proof) by stevecheng
Log in to rate this entry.
(view current ratings)

Cross-references: aliasing, band, finite, point, intervals, fixed, continuous, generated by
There are 3 references to this entry.

This is version 4 of sampling theorem, born on 2001-12-25, modified 2002-02-19.
Object id is 1143, canonical name is SamplingTheorem.
Accessed 6758 times total.

Classification:
AMS MSC94A20 (Information and communication, circuits :: Communication, information :: Sampling theory)

Pending Errata and Addenda
None.
[ View all 2 ]
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | prove | add result | add corollary | add example | add (any)