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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
Top 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 Top 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 Top
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 Top 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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