Groups > sci.electronics.design > #518616

Re: really bad oscillators

From	"Tim Williams" <tiwill@seventransistorlabs.com>
Newsgroups	sci.electronics.design
Subject	Re: really bad oscillators
Date	2018-10-06 22:55 -0500
Organization	A noiseless patient Spider
Message-ID	<ppc04a$bgb$1@dont-email.me> (permalink)
References	<k5rhrdp40aavhpffehpmnc5ipkcb91lg9j@4ax.com> <ppasno$mlt$1@dont-email.me> <4b7b87b7-b261-493f-975b-1b75364a4828@googlegroups.com>

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"whit3rd" <whit3rd@gmail.com> wrote in message 
news:4b7b87b7-b261-493f-975b-1b75364a4828@googlegroups.com...
> On Saturday, October 6, 2018 at 10:51:56 AM UTC-7, Tim Williams wrote:
>> Zener diode noise generator + bandpass + comparator.
>
> Good, but the Zener capacitance might have some bandpass as well.

Right, that sets the maximum bandwidth.  You can tone it down from there as 
you like, for whatever frequency / phase noise range you want.  Presumably, 
the smaller fraction of the distribution you take, the more sigmas you'll 
have that look "normal" around f_c.  Setting the bandwidth to be a few times 
the interpolator step would seem appropriate.

And if this is still too slow (~100s kHz would be typical), tack on a high 
frequency clock and mixer, and bandpass some more.  Of course if that 
doesn't offer enough bandwidth, you'll need to figure something else out, 
but in any case, noise generators are probably not something John has a 
shortage of. :)

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

Thread

really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-06 10:33 -0700
  Re: really bad oscillators "Tim Williams" <tiwill@seventransistorlabs.com> - 2018-10-06 12:51 -0500
    Re: really bad oscillators whit3rd <whit3rd@gmail.com> - 2018-10-06 15:16 -0700
      Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-06 15:52 -0700
      Re: really bad oscillators "Tim Williams" <tiwill@seventransistorlabs.com> - 2018-10-06 22:55 -0500
  Re: really bad oscillators George Herold <gherold@teachspin.com> - 2018-10-06 11:33 -0700
  Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-06 11:35 -0700
  Re: really bad oscillators <698839253X6D445TD@nospam.org> - 2018-10-06 18:49 +0000
  Re: really bad oscillators Steve Wilson <9fe142ac@gmail.com> - 2018-10-06 11:50 -0700
  Re: really bad oscillators bloggs.fredbloggs.fred@gmail.com - 2018-10-06 12:13 -0700
    Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-06 15:55 -0700
  Re: really bad oscillators Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2018-10-06 21:28 +0200
    Re: really bad oscillators Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2018-10-06 21:35 +0200
    Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-06 16:01 -0700
  Re: really bad oscillators bitrex <user@example.net> - 2018-10-06 21:59 -0400
    Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-07 08:05 -0700
      Re: really bad oscillators bitrex <user@example.net> - 2018-10-07 23:04 -0400
        Re: really bad oscillators John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-07 21:10 -0700
      Re: really bad oscillators bitrex <user@example.net> - 2018-10-07 23:12 -0400

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