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Re: really bad oscillators

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On 10/06/2018 01:33 PM, John Larkin wrote:
> 
> 
> A timestamper is a circuit that latches the time of arrival of a pulse
> edge. We use a clock and a binary counter as MC, the master counter
> definition of time. We extend those MC bits down into picoseconds with
> a time interpolator, adding 8 to 12 bits below the counter LSB.
> 
> One way to test a time stamper is to stamp pulses that are random in
> time, and then histogram/analyze the codes. That can catch all sorts
> of nasties, like stuck or shorted bits or interpolator problems; we've
> done the math on that. In the test set that I'm designing, I want a
> simple but really bad pulse generator, maybe around 1 MHz with tons of
> period jitter, to get good statistics and never alias against the
> master clock. Aliasing can make really weird histograms.
> 
> https://www.dropbox.com/s/vv6dqeffxrkmca3/Timestamp_Noisy_Osc.jpg?raw=1
> 
> The single inverting schmitt oscillator is probably good enough, but
> it's fun to consider other really nasty oscillators. A bad power
> supply will only help.
> 
> We have an FPGA, so I guess we could build a pseudorandom bit stream,
> filter that a little, and use that to confuse a schmitt oscillator.
> The kids might enjoy programming that.
> 
> 

Chua's circuit is the textbook chaotic oscillator:

<https://en.wikipedia.org/wiki/Chua%27s_circuit>

Adding a single capacitor to the usual "blocking oscillator" can make a 
chaotic oscillator:

"The output signal of such chaotic oscillator is a series of short term 
pulses characterized by chaotic fluctuations of time intervals between 
pulses. Such chaotic pulse signals possess a broad-band continuous power 
spectrum and short correlation length."

(PDF) Generation of broad-band chaos using blocking oscillator. 
Available from: 
<https://www.researchgate.net/publication/3323718_Generation_of_broad-band_chaos_using_blocking_oscillator>

Two sheet-beam tube oscillators, each configured as self-oscillating 
singly-balanced mixers, cross coupled to each other would probably make 
a pretty crappy oscillator

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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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