# Gaussian pulse

Discussion in 'Electronic Basics' started by thejim, Feb 12, 2006.

1. ### thejimGuest

Regarding the Gaussian pulse of transmitter it says that the spectrum
is also gaussian.
I assume that it means the frequency spectrum.Can someone please
elaborate litle on the term "Gaussian frequency spectrum".

2. ### PeteSGuest

Gaussian distribution (also known as normal distribution) is a
probability density where samples are evenly distributed about the mean
(equal energy at +/- sigma, +/- 2 sigma etc., and all points in
between) and where the peak density occurs at the mean (for a single
gaussian function).
This is also known as a bell curve because the graphical representation
resembles the shape of a bell.
If you are unfamiliar with fundamental statistics you might have a hard

http://en.wikipedia.org/wiki/Normal_distribution

or just search for Gaussian distribution.

You are correct in assuming the frequency spectrum is being referred to
- the distribution of energy in the frequency domain shows the power
density function of the transmitter in your case.

Cheers

PeteS

3. ### Bob MastaGuest

A Gaussian is a mathematical construct that is the same shape
in both the time domain and the frequency domain. Most other
functions are quite different. Typically, things that are isolated
events in one domain have broad extent in the other. Think of
a continuous sine wave in the time domain: It's spectrum is
just a single line. Conversely, a single narrow pulse in the time
domain has a broad spectrum. The Gaussian is sorta like
the "happy medium" in that it is fairly discrete but also fairly
extended, so it looks the same in both domains.

Note that a true Gaussian has infinite extent, so you will
probably never encounter one in the real world. (And how
would you know if you did?!) Usually, in order to get on
with our lives, we have to truncate the tails and accept
the consequences in the other domain.

Hope this helps!

Bob Masta