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Re: Random noise generation

From Gerhard Hoffmann <dk4xp@arcor.de>
Newsgroups sci.electronics.design
Subject Re: Random noise generation
Date 2026-10-03 13:34 +0200
Message-ID <119qp7k$o9f4$1@solani.org> (permalink)
References (7 earlier) <7kd5bldr363n3pibhjh5lb4gof9n9254c4@4ax.com> <nnd$250bca9f$3821a01b@b3a571b94a398c12> <at66bltaa1dbofd9kpop8k0ivvl6j4m103@4ax.com> <1s1zj3s.1u3fl60cacq2oN%liz@poppyrecords.invalid.invalid> <bk2dblp2o2c4gn1da6r5jnpmep4pdvjpi0@4ax.com>

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Am 25.09.26 um 16:56 schrieb john larkin:
> On Fri, 25 Sep 2026 09:22:46 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
> 
>> john larkin <jl@htigct.com> wrote:
>>
>>> On Wed, 23 Sep 2026 01:55:36 +0800, Johann 'Myrkraverk' Oskarsson
>>> <johann@myrkraverk.invalid> wrote:
>>>
>>>> On 9/23/2026 1:20 AM, john larkin wrote:
>>>>> On Wed, 23 Sep 2026 00:50:15 +0800, Johann 'Myrkraverk' Oskarsson
>>>>> <johann@myrkraverk.invalid> wrote:
>>>>>
>>>>>> On 9/23/2026 12:36 AM, john larkin wrote:
>>>>>>> On Wed, 23 Sep 2026 00:08:28 +0800, Johann 'Myrkraverk' Oskarsson
>>>>>>> <johann@myrkraverk.invalid> wrote:
>>>>>>
>>>>>> [snip]
>>>>>>>> Do you make any cryptographically secure random number generators?  I
>>>>>>>> have a personal interest in Fortuna, but am not willing to buy a product
>>>>>>>> that claims to make cryptographically secure random numbers, and does
>>>>>>>> not.
>>>>>>>
>>>>>>> No. A really good random number generator would start with a
>>>>>>> physics-based source, probably Johnson noise, and scramble that. We
>>>>>>> just want to simulate random vibration and jitter.
>>>>>>
>>>>>> Fair enough.  For cryptographical purposes, people need to be aware of
>>>>>> /three letter agencies/ subverting physics based sources.  This has been
>>>>>> mentioned in books by Schneier, so I presume you know all about it, and
>>>>>> I won't have to expand further on the subject.
>>>>>
>>>>> No, I didn't know. How can one subvert Johnson or zener noise? One
>>>>> could easily have a dozen of them and scramble hard.
>>>>>
>>>>>>
>>>>>>>
>>>>>>> Some people don't want to go off-chip, so use a bunch of bad ring
>>>>>>> oscillators.
>>>>>>
>>>>>> I believe I have somewhere an external noise generator.  Forgive me if
>>>>>> I don't recall exactly what, as that project has been dormant for some
>>>>>> time.  It's a ready made /click/ for my PIC32 development board, if I
>>>>>> recall correctly.  So please don't consider myself as one of those peo-
>>>>>> ple.
>>>>>>
>>>>>> Have you ever experimented with audio input as a physics based source?
>>>>>> I believe you won't even need a microphone, as you should be able to
>>>>>> just plug a wire in the mini-jack audio receptor, and use that like an
>>>>>> antenna.
>>>>>
>>>>> That could have bad statistics. A real random signal should have no
>>>>> statistics!
>>>>
>>>> I don't think you can get a /real random signal/ with a physical input
>>>> of some kind.  And to adjust for the bad statistics -- for now, let's
>>>> just assume so -- you can fix that on the software end.
>>>>
>>>> Read every /word/ from the ADC [1], and keep only the least significant
>>>> bit, discard the rest.  After thirty two words from the ADC you have a
>>>> single integer for the digital random number generator.
>>>>
>>>> Of course, that might not be good enough, nor fast enough, for the app-
>>>> lication, and you can mix that into a more complex R.N.G. with a /linear
>>>> feedback shift register/ -- if I recall my nomenclature correctly -- or
>>>> at the deep end of the pool, Fortuna.
>>>
>>> I'd have a number of channels. Each a zener diode, amplifier, highpass
>>> filter, and a comparator. Feed the comparators into an FPGA and
>>> scramble them digitally.
>>>
>>> A zener will make ballpark 300 nV/rthz of pretty white noise. That's
>>> easier to process than resistor Johnson noise.
>>
>> If you look at the output from a zener diode on an oscilloscope, it
>> appears to made up of jumps between discrete levels; although it may be
>> time-random it isn't voltage-random.
> 
> I posted some notes on that. I found different behavior in different
> current zones.
> 
>>
>> For a rough-and-ready audio noise generator, I used the noise of the
>> blue LED pilot light and amplified it with a quad op-amp.  i also
>> included a state-variable filter so you could select:
>>
>> Full bandwidth
>> High pass
>> Low pass
>> Narrow peak
>> Narrow notch
> 
> Was the led forward biased? What was its noise amplitude?

Absolute noise levels of some LEDs:
< 
https://www.flickr.com/photos/137684711@N07/24354944411/in/album-72157662535945536 
   >
0 dB is 1 nV/rt Hz
The LEDs are fed from NiCd 14V via 1 or 2 KOhm.
Noisewise, king of the hill is HP/Avago HLMP6000.
Optically, it is quite a dim bulb, literally.

Preamp is 10 pairs of ADA4898-2 in parallel, 220 pV/rtHz in the
flat part. The worse than 1/f noise rise towards low frequencies
comes from the undersized input coupling capacitor. It must be
much bigger than needed for the lower corner frequency since it
must short the bias resistor noise through the low-impedance DUT.
Scott Wurcer RIP, the father of AD797, AD825.. saw that immediately.
I took 2 weeks longer.

Pics to the right: some regulators, then some Zeners/avalanche diodes.

> The nice thing about zener noise is that it's big, so swamps amplifier
> noise, like 1/f.

No, Zeners are fine. In the pic, the BZX84 family the 2.7V is > 30 dB
better than the 6V8. At 5 to 7V the avalanche effect has taken over.
At 3V3 and 4V7 it starts to get worse and worse, noise-wise.
Zener and Avalanche have different signs of TK. Somewhere near 6V they
compensate each other.

In a case of scientific honesty, Prof. Zener sued the industry that
they should not use his name for avalanche diodes. He won, but the
ghost had already escaped the bottle.

I once used the BE junction of a BFR93A transistor as a noise head
and had it measured at the Weinheim amateur radio meeting. It
delivered 22 dB excess noise to > 2 GHz flat.
Now, I have such a thing + 8970B:
< 
https://www.keysight.com/us/en/product/346A/noise-source-10-mhz-18-ghz-nominal-enr-6-db.html 
   >

cheers, Gerhard

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Thread

proposal Lane W <cactus_DAC@yahoo.com> - 2026-09-20 14:27 -0600
  Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-20 13:49 -0700
    Re: proposal Lasse Langwadt <llc@fonz.dk> - 2026-09-20 23:20 +0200
      Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-20 14:35 -0700
        Re: proposal Lasse Langwadt <llc@fonz.dk> - 2026-09-21 20:11 +0200
    Re: proposal Martin Brown <'''newspam'''@nonad.co.uk> - 2026-09-20 22:46 +0100
  Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-20 14:56 -0700
    Re: proposal Lane W <cactus_DAC@yahoo.com> - 2026-09-20 17:08 -0600
      Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-20 19:11 -0700
      Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-20 19:24 -0700
        Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-20 19:36 -0700
          Re: proposal Sergey Kubushyn <ksi@koi8.net> - 2026-09-21 03:27 +0000
            Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-20 21:01 -0700
            Re: proposal Jan Panteltje <alien@comet.invalid> - 2026-09-21 06:36 +0000
              Re: proposal Sergey Kubushyn <ksi@koi8.net> - 2026-09-21 07:02 +0000
                Re: proposal Jan Panteltje <alien@comet.invalid> - 2026-09-21 07:34 +0000
              Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-21 01:26 -0700
            Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-21 17:06 +1000
  Re: proposal Don Y <blockedofcourse@foo.invalid> - 2026-09-20 14:57 -0700
  Re: proposal sobriquet <dohduhdah@yahoo.com> - 2026-09-21 03:10 +0200
    Re: proposal Lane W <cactus_DAC@yahoo.com> - 2026-09-20 20:38 -0600
    Re: proposal Jan Panteltje <alien@comet.invalid> - 2026-09-21 06:45 +0000
    Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-21 09:26 -0700
      Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-22 00:36 +0800
        Re: proposal john larkin <jl@htigct.com> - 2026-09-21 10:20 -0700
          Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-22 16:30 +1000
            Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-22 14:45 +0800
              Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-22 17:17 +1000
            Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 04:01 -0700
              Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 00:21 +1000
      Re: proposal sobriquet <dohduhdah@yahoo.com> - 2026-09-22 02:32 +0200
        Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-21 19:03 -0700
          Re: proposal sobriquet <dohduhdah@yahoo.com> - 2026-09-22 04:09 +0200
            Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-21 20:23 -0700
              Re: proposal sobriquet <dohduhdah@yahoo.com> - 2026-09-22 06:10 +0200
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-22 16:57 +1000
                Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 04:15 -0700
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 00:38 +1000
                Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 08:08 -0700
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 01:49 +1000
                Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-23 00:04 +0800
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-24 18:27 +1000
                Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-24 17:07 +0800
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 01:41 +1000
                Re: proposal Lane W <cactus_DAC@yahoo.com> - 2026-09-24 10:02 -0600
                Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-25 04:00 +0800
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 16:37 +1000
                Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 04:04 -0700
                Re: proposal sobriquet <dohduhdah@yahoo.com> - 2026-09-22 16:38 +0200
                Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 08:22 -0700
                Re: proposal Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-23 00:08 +0800
                Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 09:36 -0700
                Random noise generation (was: Re: proposal) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-23 00:50 +0800
                Re: Random noise generation (was: Re: proposal) john larkin <jl@htigct.com> - 2026-09-22 10:20 -0700
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 03:51 +1000
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-23 01:55 +0800
                Re: Random noise generation john larkin <jl@htigct.com> - 2026-09-22 17:35 -0700
                Re: Random noise generation Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-09-23 15:14 +0000
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-23 09:12 -0700
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-24 17:39 +0800
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 02:05 +1000
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-25 01:39 +0800
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-24 18:26 -0700
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 16:46 +1000
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-25 07:51 -0700
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-26 06:49 +0800
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 07:25 -0700
                Re: Random noise generation ehsjr <ehsjr@verizon.net> - 2026-09-26 12:57 -0400
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-27 06:29 +0800
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 16:17 -0700
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-27 08:25 +0000
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-27 03:10 -0700
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 15:48 +1000
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 08:34 -0700
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 15:45 +1000
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 15:48 +1000
                Re: Random noise generation liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-25 09:22 +0100
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-25 07:56 -0700
                Re: Random noise generation Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-09-25 15:36 +0000
                Re: Random noise generation John R Walliker <jrwalliker@gmail.com> - 2026-09-25 16:59 +0100
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 08:42 -0700
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-25 17:19 +0000
                Re: Random noise generation Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2026-09-26 04:08 +0800
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-26 09:08 +0000
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-26 09:09 +0000
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 21:22 +1000
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 08:57 -0700
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 11:37 -0700
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-27 08:25 +0000
                Re: Random noise generation Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 20:47 +1000
                Re: Random noise generation Jan Panteltje <alien@comet.invalid> - 2026-09-26 18:00 +0000
                Re: Random noise generation john larkin <jl@htigct.com> - 2026-09-25 17:09 -0700
                Re: Random noise generation liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-25 22:12 +0100
                Re: Random noise generation Jeroen Belleman <jeroen@nospam.please> - 2026-09-26 10:14 +0200
                Re: Random noise generation liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-26 14:37 +0100
                Re: Random noise generation Jeroen Belleman <jeroen@nospam.please> - 2026-09-26 23:09 +0200
                Re: Random noise generation liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-27 09:15 +0100
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-09-26 09:01 -0700
                Re: Random noise generation liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-26 19:45 +0100
                Re: Random noise generation Gerhard Hoffmann <dk4xp@arcor.de> - 2026-10-03 13:34 +0200
                Re: Random noise generation Jeroen Belleman <jeroen@nospam.please> - 2026-10-03 16:03 +0200
                Re: Random noise generation john larkin <jl@glen--canyon.com> - 2026-10-03 08:42 -0700
                Re: Random noise generation brian <nospam@b-howie.co.uk> - 2026-10-06 05:39 +0100
                Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 01:01 +1000
    Re: proposal someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-09-21 21:00 +0000
      Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-22 17:10 +1000
        Re: proposal john larkin <jl@glen--canyon.com> - 2026-09-22 04:21 -0700
          Re: proposal Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 02:17 +1000

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