Hello Neven,
It is always interesting to read the SSCG posts. You never really know who
is listening. Here are some comments on recent posts.
To get the best correlation between a receiver in peak detector or QP mode
set a spectrum analyzer RBW to 100kHz which is a 3dB bandwidth. The 120kHz
I would like to thank sincerely to all who responded, I appreciate it. I am not
going to react to any discussions on whether it is cheating or not :), it was
not anywhere in my mind when I posted the question and I hope this topic does
not degrade :).
But, I'd like to summarize a
Hi Neven,
I can also confirm that you should see a decrease in amplitude in peak mode for
SS clocking. I use my simple handheld Thurlby Thander PSA2701T peak-reading
spectrum analyzer to demo this during my EMC seminars.
___
Kenneth Wyatt
Wyatt Technical Services LLC
...@comcast.net
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Sent: Friday, February 10, 2012 2:31 PM
Subject: Re: [PSES] Spread-Spectrum Clock Question
Hi Neven,
I can also confirm that you should see a decrease in amplitude in peak mode for
SS clocking. I use my simple handheld Thurlby Thander PSA2701T peak
Hello,
I wonder if anyone can help with a question I have on spread spectrum clock
(SSC).
I am trying to validate the effectiveness of a SSC chip to reduce emission. I
measure with the peak detector. With the SSC enabled (up to 2.5% down-spread) I
expect the level measured with a
Neven,
Your suspicion regarding the modulating frequency is on the right track.
Normally, the mod freq is set just above the audio range. There's something
very wrong if the specs only allow 3 to 100 Hz. Is that a misprint perhaps?
You should be able to see the spread harmonics easily at 120
-seminars.com
Date: Thu, 9 Feb 2012 17:50:40 -0700
To: neve...@comcast.net
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Spread-Spectrum Clock Question
Neven,
Your suspicion regarding the modulating frequency is on the right track.
Normally, the mod freq is set just above the audio range
Neven,
I've worked with the EMC Engineers at Lexmark who invented the
spread-spectrum clock generator (SSCG), since before they started its
development. I used SSCG in a number of products that I designed at
Lexmark. Below is my understanding of how SSCG works, based on numerous
discussions with
-Spectrum Clock Question
Neven,
Your suspicion regarding the modulating frequency is on the right track.
Normally, the mod freq is set just above the audio range. There's something
very wrong if the specs only allow 3 to 100 Hz. Is that a misprint perhaps?
You should be able to see the spread
yeah! what John says.
He now owns the consulting business started by Don Bush, and worked with all
those guys long ago.|
ps. I don't recall ever meeting John. But I did work with the guys listed on
the patent, when Lexmark was IBM.
I recall the big surprise for me with this SSCG was we (Boca)
Why is a spread-spectrum clock cheating?
If the measurement BW is an accurate portrayal of the victims protected by
the levied requirement, and if the QP detector is an accurate assessment of
the nuisance value of the interfering signal modulation, then why is
spreading the spectrum over a range
The common spreading freq at the time meant that the interference passed thru
the sensitive band at a frequency higher than our human visual and auditory
perceptions, (It could be detected by comparing side by side, two systems, one
with and one without) but for those of us that opinionated
@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Spread-Spectrum Clock Question
yeah! what John says.
He now owns the consulting business started by Don Bush, and worked with all
those guys long ago.|
ps. I don't recall ever meeting John. But I did work with the guys listed
on the patent, when Lexmark was IBM.
I
Probably explains why my wifi link is slower than advertised!!! It is the
error correction time...
From: Ed Price edpr...@cox.net
To: emc-p...@ieee.org
Sent: Friday, February 10, 2012 2:29 AM
Subject: RE: [PSES] Spread-Spectrum Clock Question
And we’ve
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