Re: Distorted Sine Wave

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Sujet : Re: Distorted Sine Wave
De : joegwinn (at) *nospam* comcast.net (Joe Gwinn)
Groupes : sci.electronics.design
Date : 31. May 2024, 20:10:32
Autres entêtes
Message-ID : <m38k5jlbqo39gr9223b0vg93e8lrbrpurr@4ax.com>
References : 1 2 3 4 5 6 7 8 9 10 11
User-Agent : ForteAgent/8.00.32.1272
On Fri, 31 May 2024 18:54:06 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:

On Fri, 31 May 2024 11:34:46 -0400, Joe Gwinn wrote:
>
On Thu, 30 May 2024 16:24:25 -0700, john larkin <jl@650pot.com> wrote:
 
On Thu, 30 May 2024 18:53:29 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
>
On Thu, 30 May 2024 14:56:30 -0700, john larkin <jl@650pot.com> wrote:
>
On Thu, 30 May 2024 16:06:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
>
On Thu, 30 May 2024 15:02:44 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>
On 2024-05-29 18:59, Joe Gwinn wrote:
On Wed, 29 May 2024 22:11:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
 
Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 29 May 2024 13:42:13 -0700, john larkin wrote:
>
On Wed, 29 May 2024 21:43:54 +0200, Arie de Muijnck
<noreply@ademu.com>
wrote:
>
On 2024-05-29 19:07, Cursitor Doom wrote:
Gentlemen,
>
Whilst fault-finding on my HP 8566B spectrum analyzer, I've
found the 10Mhz reference oscillator is generating an
'unsatisfactory waveform'
which may be causing the device to be unable to lock it's
main PLL. I've come across this waveshape before, but mostly
with oscillators I was building and in the process of trying
to iron out the wrinkles of and certainly NOT a critical
reference oscillator from a respected manufacturer. Can
anyone tell what's most likely going on here?
>
https://disk.yandex.com/i/z6fYbeVfPRK7aA
>
>
Looks like reflections in the cable. Try the 50 Ohm
termination.
>
Arie
>
If the drive is a sine wave, a cable can't generate that 2nd
harmonic.
>
I don't understand how a reflection can account for it either.
THe cable's only 4' long! However, with the 50 ohm input
enabled, the 2nd harmonic disappears. It's just one of those
inexplicable mysteries that no one knows the answer to. :)
>
That?s pretty diagnostic. There must be an LC filter on the
output?mis-terminating it will cause all sorts of
frequency-response whoopdedoos.
 
It also occurs to me that if there is a diode in series with a
resistor somewhere, the impedance presented to the feed coax may
be 50 ohms for positive input voltage, and say 10 Kohm for
negative.  At the very least one could get an inverted reflection
on negative.
 
Joe Gwinn
 
Yeah, or an emitter follower.  Good point.
>
Plus some LC filter wiggles, to distort and smooth things.
>
I dug around and found a copy of the HP 8566B spectrum analyzer
service manual.  The 10 MHz ref input is an amplifier driving a
mixer,
with not hint of for instance a TTL input.  So, the problem must be
elsewhere.  Or, it's just busted.
>
.<chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://
xdevs.com/doc/HP_Agilent_Keysight/
HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf>
>
Joe Gwinn
>
334 pages! Where is the issue?
>
The pagination was unclear, so I didn't see a way to say.  How I found
it was to look at the schematics.  Look for module A22.  Don't think
search works on such images, but visual search didn't take that long.
>
Joe Gwinn
>
Too much work for free consulting.
 
I took another look.  There is a page reference on the right edge, near
the bottom, which is not marked as a page X of Y, but is.
 
Anyway, look at pages 59 and 77.  At 77, look for A22 in the lower left
region.  Just above, look for INT and EXT jacks.  The EXT jack is where
an external reference enters.
 
Joe Gwinn
>
It's just a block diagram of the reference oscillator module. There's no
detailed schematic of the oscillator itself. At least that's the case with
the PDF version of the Service Manual I have.

It's probably in the book that I don't have, if it was ever released.

Joe Gwinn

Date Sujet#  Auteur
29 May 24 * Distorted Sine Wave69Cursitor Doom
29 May 24 +- Re: Distorted Sine Wave1john larkin
29 May 24 `* Re: Distorted Sine Wave67Arie de Muijnck
29 May 24  `* Re: Distorted Sine Wave66john larkin
29 May 24   `* Re: Distorted Sine Wave65Cursitor Doom
29 May 24    +- Re: Distorted Sine Wave1Joe Gwinn
29 May 24    +* Re: Distorted Sine Wave2Jeroen Belleman
29 May 24    i`- Re: Distorted Sine Wave1Cursitor Doom
30 May 24    +* Re: Distorted Sine Wave56Phil Hobbs
30 May 24    i`* Re: Distorted Sine Wave55Joe Gwinn
30 May 24    i `* Re: Distorted Sine Wave54Phil Hobbs
30 May 24    i  `* Re: Distorted Sine Wave53Joe Gwinn
30 May 24    i   `* Re: Distorted Sine Wave52john larkin
31 May 24    i    `* Re: Distorted Sine Wave51Joe Gwinn
31 May 24    i     `* Re: Distorted Sine Wave50john larkin
31 May 24    i      `* Re: Distorted Sine Wave49Joe Gwinn
31 May 24    i       +* Re: Distorted Sine Wave9Cursitor Doom
31 May 24    i       i`* Re: Distorted Sine Wave8Joe Gwinn
1 Jun 24    i       i `* Re: Distorted Sine Wave7Cursitor Doom
1 Jun 24    i       i  +- Re: Distorted Sine Wave1Cursitor Doom
1 Jun 24    i       i  `* Re: Distorted Sine Wave5Joe Gwinn
1 Jun 24    i       i   `* Re: Distorted Sine Wave4Cursitor Doom
1 Jun 24    i       i    `* Re: Distorted Sine Wave3Joe Gwinn
1 Jun 24    i       i     `* Re: Distorted Sine Wave2Cursitor Doom
2 Jun 24    i       i      `- Re: Distorted Sine Wave1Joe Gwinn
31 May 24    i       `* Re: Distorted Sine Wave39Cursitor Doom
31 May 24    i        `* Re: Distorted Sine Wave38Joe Gwinn
31 May 24    i         `* Re: Distorted Sine Wave37Cursitor Doom
1 Jun 24    i          `* Re: Distorted Sine Wave36boB
1 Jun 24    i           `* Re: Distorted Sine Wave35boB
1 Jun 24    i            `* Re: Distorted Sine Wave34Cursitor Doom
1 Jun 24    i             `* Re: Distorted Sine Wave33Jeroen Belleman
1 Jun 24    i              `* Re: Distorted Sine Wave32Cursitor Doom
2 Jun 24    i               `* Re: Distorted Sine Wave31piglet
2 Jun 24    i                +* Re: Distorted Sine Wave9piglet
2 Jun 24    i                i`* Re: Distorted Sine Wave8Jeroen Belleman
2 Jun 24    i                i `* Re: Distorted Sine Wave7Cursitor Doom
2 Jun 24    i                i  +* Re: Distorted Sine Wave2Phil Hobbs
2 Jun 24    i                i  i`- Re: Distorted Sine Wave1Cursitor Doom
2 Jun 24    i                i  `* Re: Distorted Sine Wave4Jeroen Belleman
2 Jun 24    i                i   `* Re: Distorted Sine Wave3Cursitor Doom
2 Jun 24    i                i    `* Re: Distorted Sine Wave2Jeroen Belleman
2 Jun 24    i                i     `- Re: Distorted Sine Wave1Cursitor Doom
2 Jun 24    i                `* Re: Distorted Sine Wave21Cursitor Doom
2 Jun 24    i                 `* Re: Distorted Sine Wave20piglet
2 Jun 24    i                  `* Re: Distorted Sine Wave19Cursitor Doom
2 Jun 24    i                   +* Re: Distorted Sine Wave6John R Walliker
2 Jun 24    i                   i`* Re: Distorted Sine Wave5Cursitor Doom
2 Jun 24    i                   i +* Re: Distorted Sine Wave2Jan Panteltje
2 Jun 24    i                   i i`- Re: Distorted Sine Wave1Cursitor Doom
3 Jun 24    i                   i `* Re: Distorted Sine Wave2John R Walliker
5 Jun 24    i                   i  `- Re: Distorted Sine Wave1Cursitor Doom
2 Jun 24    i                   `* Re: Distorted Sine Wave12Joe Gwinn
2 Jun 24    i                    +* Re: Distorted Sine Wave7Cursitor Doom
2 Jun 24    i                    i`* Re: Distorted Sine Wave6Joe Gwinn
2 Jun 24    i                    i `* Re: Distorted Sine Wave5Cursitor Doom
3 Jun 24    i                    i  `* Re: Distorted Sine Wave4Joe Gwinn
3 Jun 24    i                    i   `* Re: Distorted Sine Wave3Cursitor Doom
3 Jun 24    i                    i    `* Re: Distorted Sine Wave2Jeroen Belleman
3 Jun 24    i                    i     `- Re: Distorted Sine Wave1Cursitor Doom
2 Jun 24    i                    `* Re: Distorted Sine Wave4Jeroen Belleman
2 Jun 24    i                     `* Re: Distorted Sine Wave3Joe Gwinn
2 Jun 24    i                      `* Re: Distorted Sine Wave2Jeroen Belleman
3 Jun 24    i                       `- Re: Distorted Sine Wave1Joe Gwinn
30 May 24    +* Re: Distorted Sine Wave4boB
30 May 24    i+* Re: Distorted Sine Wave2john larkin
30 May 24    ii`- Re: Distorted Sine Wave1boB
2 Jun 24    i`- Re: Distorted Sine Wave1Cursitor Doom
30 May 24    `- Re: Distorted Sine Wave1Lasse Langwadt

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