hi Jim,
I worked for Andersen Labs for a while. We built Saw filters and oscillators
for all kinds of applications. The oscillators were fixed frequency or 1% BW
VCXOs. I was impressed with the phase noise we measured. Even VCXOs had better
then 100 dB at 1 KHz dBC. Above 1 GHz there were internal multipliers that
degraged the phase noise down to around -90 dBC. Sometimes units failed or
drifted out of spec after the cases were welded. I pulled a few out of the
trash for the junk box. I'll get a good DDS someday and press one into service.
fc
Jim Miller <[EMAIL PROTECTED]> wrote:
I was wondering about that. The SAW resonators I've seen so far don't have
very high Q but I haven't done a lot of research on them. I was reading
Intro to RF Design last night looking for some more insight on oscillators
and noticed that phase noise was inversely proportional to Q^4. So thought
that SAW oscillators might be noticeably noiser than a XTAL oscillator close
in.
Of course since the frequencies seldom overlap it would be comparing apples
to oranges. The only XTAL oscillator implementations I've seen at SAW
frequencies have been based on filtering the output to pick off highorder
distortion products. I would imagine that such an approach magnifies any
phase noise present by at least the order of the distortion product;
probably worse.
Has anyone got some references to SAW oscillator phase noise measurements?
FWIW, Digikey has some ECS SAW resonators at 400Mhz for $3.50 or so each.
I'll probably buy some just to play with.
Of course now I need to get a faster scope...I thought a TEK475 was going to
be plenty. Silly me. Any suggestions for a supplement for highspeed logic
work?
73
jim ab3cv
----- Original Message -----
From: "FRANCIS CARCIA"
To:
Sent: Sunday, April 16, 2006 6:35 PM
Subject: Re: [soft_radio] Re: SDR Basics
A good SAW oscillator will do 500 mHz. with the same performance as a
crystal
oscillator.
Yahoo! Groups Links
[Non-text portions of this message have been removed]
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/soft_radio/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
