This is a real hardcore tech question.  Before everyone bury yourself 
too deep into the term BFSK, BPSK, and BFSK, I'll use example to 
explain.  By the way, I like all the other explanation from Sanford and 
Alexander.  Since we're talking about phase modulation, it works the 
same way as the FM stereo.  The FM stereo that we listens to allows us 
to change staions in different frequency.  First station would have a 
fixed frequency than the second, and the receiver determines two 
stations by the change in phase.  For instance, the first station starts 
at phase 0 degree while the second station starts at 90 degree.  Thus 
changing the frequency between the two stations correspond to change in 
phase, and so the name Frequency Modulation came about.

Now back to BFSK, BPSK, and BFSK, the scenario is similar but with 
different condition.  The frequency is fixed, so what other property is 
there that can change in correspond to a change in phase?  I'll leave 
the answer to the reader.  Hope this helps.

Steve

-----Original Message-----
From: "Blair Templeton" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Date: Thu, 18 Dec 2003 10:58:47 +0000
Subject: [SOCALWUG] Difference between Frequency and Phase?

> Hello,
> 
> Im having difficulties understanding exactly what Phase means, Im
> reading 
> 802.11 Wi-Fi handbook
> (Neil Reid&Ron Seide) which explains that frequency is the complete
> cycle of 
> a wave.
> Phase is where the wave begins its cycle. Makes sense I guess.
> What becomes confusing is BFSK and BPSK, BFSK sends an on or off bit
> with 
> each frequency,
> BPSK sends two states, a "one" with one phase and "zero" with another
> phase.
> If phase just determines at what point in time a frequency begins its
> cycle, 
> how can there be a modulation scheme based on phase?
> 
> Thanks
> 
> 
> --------------------
> "Computer games don't affect kids, I mean if Pac Man affected us as
> kids, 
> we'd all run around in a darkened room munching pills and listening to 
> repetitive music." - Kristian Wilson, Nintendo, Inc, 1989.
> 
> _________________________________________________________________
> Worried about inbox overload? Get MSN Extra Storage now!  
> http://join.msn.com/?PAGE=features/es

Reply via email to