Dan,

if there is no echoe, it may be that it's a hot potato. Can't help being curious about your problem. Know guys who may be able to help you.
an engineering definition of microphonics as a source of "noise".
think you have to decide whether 'noise'=wide spectra incidents in your CW or 'microphonics'= low freq modulation caused  by mech/ferro/pieze phenomenons from e.g. ceramic components in your VCO.
a measurement technique
direct measurements in the VCO use to be misleading, spec analyser on output better information.
an explanation of the physics of microphonics i.e. how motion is required to generate what degree of noise.
like your bicycle generator that whistles and groans against your tire. One good source: Relva C. Buchanan, Uni of Illinois, ISBN 0-8247-7501-5, if you have cercaps, which you certainly have.

What's your CW? And product? Analogue? Digitized?

My best tips: contact HP, if you have a friend there. They know 'everything' in that game. E.g. this one:
http://search.hp.com/gwuseng/query.html?col=hpcom+ccen+ccenfor <http://search.hp.com/gwuseng/query.html?col=hpcom+ccen+ccenfor&qp=&qs=&qc=&la=en&fs=&qt=noise&ex=&rq=0&oq=&qm=0&ql=&qr=1&st=11&nh=10&lk=1&rf=0&uf=1> &qp=&qs=&qc=&la=en&fs=&qt=noise&ex=&rq=0&oq=&qm=0&ql=&qr=1&st=11&nh=10&lk=1&rf=0&uf=1

and this one:

http://www.hp.com/country/us/eng/contact_us.html <http://www.hp.com/country/us/eng/contact_us.html>

Regards

Ingemar Hernefjord
Ericsson Microwave Systems




-----Original Message-----
From: Tenison Stone [mailto:[log in to unmask]]
Sent: den 2 januari 2003 21:57
To: [log in to unmask]
Subject: Re: [TN] A shot in the dark



Dan,

Since no one has answered, I will try.

We make RF products and microphonics (cow bell is the term used here) has been a problem.  The problem was traced to the VCO.

Let me know if you need more information.  I am not the design engineer, so my help is limited.

Tenison Stone
Manufacturing Engineer
Telex Communications
1930 West First Street
Blue Earth, MN  56013
507-526-3205   x2164
507-526-3059 (fax)



        "Dan R. Johnson" <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>


12/05/2002 05:01 PM
Please respond to "TechNet E-Mail Forum."; Please respond to "Dan R. Johnson"



        To:        [log in to unmask]
        cc:
        Subject:        [TN] A shot in the dark



Maybe someone on Technet knows or knows someone who does know about microphonics as an error factor in RF circuits. I need to have an outside source for things like;
-an engineering definition of microphonics as a source of "noise".
-a measurement technique
-an explanation of the physics of microphonics i.e. how motion is required to generate what degree of noise.

Thanks,
Dan
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