maximum hop frequency vs. channel spacing

[Kuan Zhou]

Hi,

I have a question regarding the design of PLLs. A PLL could have a
channel spacing of 200kHz. And it could have a maximum frequency hop of
60MHz. What is the difference between these two concepts? Does it mean
that the maximum frequency hop has to be integer multiple times of the
channel spacing?

Is this maximum frequency hop a random number? How is it defined?

Any info is appreciated!!

Kuan

 

[Andrew Beckett]

On Sun, 21 May 2006 18:08:58 -0400, Kuan Zhou <koy2@cisunix.unh.edu> wrote:

Hi,

I have a question regarding the design of PLLs. A PLL could have a
channel spacing of 200kHz. And it could have a maximum frequency hop of
60MHz. What is the difference between these two concepts? Does it mean
that the maximum frequency hop has to be integer multiple times of the
channel spacing?

Is this maximum frequency hop a random number? How is it defined?

Any info is appreciated!!

Kuan

A better place to ask design-related questions is on
http://www.designers-guide.org/Forum

I'm not certain I understand your question, but perhaps that's just a matter of
knowing what the terms mean in the context of a PLL. I suspect they are talking
about the fact that you can tune the frequency synthesizer to produce output
frequencies in a 60MHz range, in steps of 200MHz - presumably by controlling the
divide ratios in the PLL.

Regards,

Andrew.
--
Andrew Beckett
Principal European Technology Leader
Cadence Design Systems, UK.