Groups > sci.electronics.design > #451120

Re: Low Frequency 3rd Overtone Crystal Osc

From	rickman <gnuarm@gmail.com>
Newsgroups	sci.electronics.design
Subject	Re: Low Frequency 3rd Overtone Crystal Osc
Date	2017-03-09 23:36 -0500
Organization	A noiseless patient Spider
Message-ID	<o9tabc$t7$1@dont-email.me> (permalink)
References	<o9q1nn$vi7$1@dont-email.me> <o9t21p$kpc$1@dont-email.me>

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On 3/9/2017 9:15 PM, Tim Williams wrote:
> FYI, crystal overtones are just that -- overtones, not harmonics.
> They're usually a little bit above harmonic.  There may be more, and
> stronger, spurious modes around the overtone as well (depends on cut and
> holder design), and the tempco will be a lot stronger (also depends on
> cut).
>
> Normally, overtone crystals are cut for the purpose, to account for all
> of this.
>
> If you're going to do it, please do report back how well it worked out
> -- if you can, try to plot the impedance and bandwidth of the overtone,
> and the spurs around it, and see what happens at different
> temperatures.  I would expect a tuning-fork style crystal to have a
> strong overtone, but I don't know that it will be useable.  Good luck!
>
> On a related note, I have a 100kc crystal handy -- but it's not 120,
> and, as you might guess from the "kc", it's somewhat antique (dated
> 1959ish I think it was).  Quite stately in its metal can. :-)  Looks
> like a contemporary electrolytic capacitor, or octal audio transformer,
> but just two round pins.

Thanks for the offer, but I don't want crystals made in Kansas City.  ;)

I'm avoiding the overtone thing.  All I need is an unstable oscillator. 
I'm going to find a 120 kHz crystal (not made in Kansas City) or I can 
use a 240 kHz crystal.  120 kHz would be lower power, but if I can trust 
my simulations, the oscillator power is going to be true flea power, 
perhaps not even reaching 1 uW.  So doubling that at 240 kHz won't be a 
problem.  This won't run all the time anyway, so power isn't as crucial 
as the circuit that runs all the time, but power consumption can add up 
if you aren't careful about every little piece.

While I wait for crystal makers to get back to me I am looking at tuning 
the crystal.  I've found a couple of varactors that might do the job 
although you wouldn't know by the simulation.  Maybe my circuit isn't so 
good, but I can't get a change in load capacitors to change the 
frequency of the circuit in a measurable way.

-- 

Rick C

Thread

Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-08 17:51 -0500
  Re: Low Frequency 3rd Overtone Crystal Osc Jon Elson <jmelson@wustl.edu> - 2017-03-08 17:04 -0600
    Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-08 19:57 -0500
    Re: Low Frequency 3rd Overtone Crystal Osc Robert Baer <robertbaer@localnet.com> - 2017-03-10 00:01 -0800
  Re: Low Frequency 3rd Overtone Crystal Osc dagmargoodboat@yahoo.com - 2017-03-08 18:02 -0800
    Re: Low Frequency 3rd Overtone Crystal Osc John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-08 18:13 -0800
      Re: Low Frequency 3rd Overtone Crystal Osc Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-09 09:11 -0500
        Re: Low Frequency 3rd Overtone Crystal Osc John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-09 08:14 -0800
          Re: Low Frequency 3rd Overtone Crystal Osc Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-09 11:24 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-11 11:20 -0500
      Re: Low Frequency 3rd Overtone Crystal Osc Neon John <no@never.com> - 2017-03-09 16:24 -0500
        Re: Low Frequency 3rd Overtone Crystal Osc John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-09 14:23 -0800
          Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-09 18:16 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc Neon John <no@never.com> - 2017-03-13 19:59 -0400
            Re: Low Frequency 3rd Overtone Crystal Osc John Larkin <jjlarkinxyxy@highlandtechnology.com> - 2017-03-13 17:29 -0700
              Re: Low Frequency 3rd Overtone Crystal Osc bill.sloman@ieee.org - 2017-03-13 18:43 -0700
            Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-13 21:54 -0400
      Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-10 10:15 +0000
    Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-08 22:33 -0500
      Re: Low Frequency 3rd Overtone Crystal Osc o pere o <me@somewhere.net> - 2017-03-09 15:39 +0100
      Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-09 09:41 -0500
        Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-09 09:43 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-09 11:17 -0500
            Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-09 20:42 -0500
              Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-09 20:55 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc piglet <erichpwagner@hotmail.com> - 2017-03-11 07:37 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-11 03:15 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc piglet <erichpwagner@hotmail.com> - 2017-03-11 09:52 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-11 08:54 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-11 09:00 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc Jasen Betts <jasen@xnet.co.nz> - 2017-03-11 23:58 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-11 22:13 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-13 11:20 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-13 11:47 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-13 23:44 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-03-13 15:55 -0700
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-13 19:58 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc Jasen Betts <jasen@xnet.co.nz> - 2017-03-14 04:48 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-14 13:37 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-14 22:29 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-14 20:59 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-03-15 10:40 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-15 12:44 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-16 08:20 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-16 02:51 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-16 09:28 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-16 04:40 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc bill.sloman@ieee.org - 2017-03-16 05:09 -0700
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-16 12:47 -0400
                Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-17 00:22 +0200
                Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-16 19:14 -0400
    Re: Low Frequency 3rd Overtone Crystal Osc John S <Sophi.2@invalid.org> - 2017-03-13 05:51 -0500
      Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-13 08:39 -0400
  Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-09 21:09 -0500
  Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-09 20:15 -0600
    Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-09 23:36 -0500
      Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-10 19:02 -0600
        Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-11 01:15 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-11 11:04 +0200
          Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-11 09:31 +0000
      Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-11 09:15 +0000
        Re: Low Frequency 3rd Overtone Crystal Osc bitrex <bitrex@de.lete.earthlink.net> - 2017-03-11 10:50 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-11 16:46 +0000
        Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-11 15:36 -0500
          Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-11 23:50 +0000
            Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-11 17:59 -0600
              Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-12 08:44 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-12 20:23 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-13 12:21 +0000
                Re: Low Frequency 3rd Overtone Crystal Osc "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-03-14 03:30 -0500
                Re: Low Frequency 3rd Overtone Crystal Osc "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> - 2017-03-14 20:50 +0000
  Re: Low Frequency 3rd Overtone Crystal Osc Robert Baer <robertbaer@localnet.com> - 2017-03-09 23:57 -0800
    Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-10 05:51 -0500
    Re: Low Frequency 3rd Overtone Crystal Osc Mike Jones <mikejones@gmail.com> - 2017-03-10 06:03 -0600
  Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-10 15:34 +0200
  Re: Low Frequency 3rd Overtone Crystal Osc Tim Wescott <tim@seemywebsite.really> - 2017-03-11 12:51 -0600
    Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-12 00:33 +0200
      Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-12 01:00 -0500
        Re: Low Frequency 3rd Overtone Crystal Osc upsidedown@downunder.com - 2017-03-12 10:45 +0200
          Re: Low Frequency 3rd Overtone Crystal Osc rickman <gnuarm@gmail.com> - 2017-03-12 18:32 -0400
    Re: Low Frequency 3rd Overtone Crystal Osc Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-13 11:26 -0400

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