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Wideband Synthesizer + VCO - RF Cafe Forums
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gui076
Post subject: Wideband Synthesizer + VCO Posted: Mon May
05, 2008 10:01 am
Captain
Joined: Mon May 05, 2008 9:56
am
Posts: 15
Location: France
Hello all,
I would like
to design a synthesizer which will work from 900 MHz to 2100 MHz. I
have seen on the net that VCOs are not very wideband. So my question
is how design a synthesizer for a wide frequency purpose ? using several
VCOs ? Multipliers ?
Thanks for your help.
Guillaume
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mac
Post subject: Posted: Tue May 06, 2008 6:58
am
Captain
Joined: Fri Nov 02, 2007 3:45 am
Posts:
8
Location: germany
Hi,
look for Synergy VCOs they have some
wideband vcos in stock
DCMO90220-12 might be o.k
or
use two overlapping ones - you can
build a synthesizer with the
analog devices pll
chips like ADF4107 etc up to 6ghz and that vcos
pretty easy-
hope that helps
regards
mac
_________________
regards
mac
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gui076
Post subject: Posted: Tue May 06, 2008 7:55 am
Captain
Joined: Mon May 05, 2008 9:56 am
Posts: 15
Location: France
Hi,
I have the synthesizer from Analog Device but the voltage
command Vp will supply only until 5V if i have well understood. The
Synergy VCO has to be tune to 24V in order to deliver 2200 MHz.
I'm not an expert in synthesizers
Guillaume
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mac
Post subject: wideband synthesizer, active loop filterPosted:
Wed May 07, 2008 7:58 am
Captain
Joined: Fri Nov
02, 2007 3:45 am
Posts: 8
Location: germany
Well,
you
can use an active loop filter instead of
a passive one with an opamp
boosting your
tuning voltage up to 24Volts - analog devices has
got a pll design tool
called adisim you can downlod for free - this
will help in
designing the loop filter anyway
and you can choose
your
filter topology -
use an op with low noise characteristics
in the end, it depends on your specifications - if phase noise
and / or
tuning speed are not your primary goals you can use single
chip plls
from other vendors aswell
but remember
synthesizer
design is always a compromise between
tuning width/ speed / phase
noise etc. the more your specification demands the more complex things
will get very soon -
good luck
mac
_________________
regards
mac
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gui076
Post subject: Posted:
Mon May 12, 2008 11:09 am
Captain
Joined: Mon May 05,
2008 9:56 am
Posts: 15
Location: France
Hi mac,
Ok
for the Op Amp, i have more informations about it and my circuit will
be defined for a 12V maximum voltage, so i will try to find some VCOs
in this range of voltage.
Regards
Guillaume
Posted 11/12/2012
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