White Noise Source

[Chiron]

I need a source of white noise (audio). It doesn't have to be perfect.

I seem to recall that you could use a zener diode as a white noise
source. Is this true? Are there any other possibilities? I anticipate
using a 9-V battery for my power, and a few transistors to amplify the
signal to drive earphones.

You may ask, "why the heck would he want to do that?" Good question:

http://en.wikipedia.org/wiki/Electronic_voice_phenomenon

Since I believe that the chances of there being anything to this are just
about zero, I don't want to invest a whole lot of effort in doing it.



--
Do not apply to broken skin.

 

[Phil Allison]

"Chiron"

I need a source of white noise (audio). It doesn't have to be perfect.

** I think you will find this microwave sauce recipe most satisfactory:

http://allrecipes.com.au/recipe/10834/cheesy-white-sauce.aspx

Not to mention tasty too.

And may I supply a word of advice -

leave the imaginary voices to the experts -

ie the genuine schizophrenics.




.... Phil

 

[Bob Masta]

On Thu, 09 Feb 2012 08:13:16 GMT, Chiron
<chiron613@gmail.com> wrote:

I need a source of white noise (audio). It doesn't have to be perfect.

I seem to recall that you could use a zener diode as a white noise
source. Is this true? Are there any other possibilities? I anticipate
using a 9-V battery for my power, and a few transistors to amplify the
signal to drive earphones.

You may ask, "why the heck would he want to do that?" Good question:

http://en.wikipedia.org/wiki/Electronic_voice_phenomenon

Since I believe that the chances of there being anything to this are just
about zero, I don't want to invest a whole lot of effort in doing it.

Download my Daqarta software... it's free for signal
generation use. Midway down the Generator dialog, click the
left Waveform Controls button. Click Wave on the dialog that
appears and select Noise: White. Toggle the Generator
button on in the main toolbar. The first time the Generator
goes on the volume control dialog will pop up, plus a
cautionary message about loud levels. You'll need to cancel
the message before the sound starts. (In WinXP you may also
need to unMute, at the bottom of that dialog.) Later, you
can open the volume dialog via the F9 key at any time.

Now I'm going to give away a secret: In the next version of
Daqarta (v7.00, in a month or so) there will be a whole Help
section on EVP-related stuff, and a demo on how to hear it
for yourself. Well, not exactly what the woo-woo folks are
talking about, but a phenomenon I call "Phantom Signals"
that I think is at the root of the EVP nonsense... as well
as "dental radio".

The trick for phantom signals is to use headphones and put
the white noise in *one ear only*. The loudness should be
about 30-40 dB above your detection threshold. (You'll need
to be in a fairly quiet room, with no music, TV, or voices.)


I'll provide a simple way to set that level. Let me know if
you want me to explain a manual approach here. It's not
super-critical, but it needs to be loud enough to hear
easily, but not too loud.

Listen for a few minutes, and you will start to hear a
"radio station". You might hear music or voices, but you
won't be able to tell exactly what the song is, or
understand what they are talking about... nevertheless
you'll be convinced there is a "signal" there. You might
categorize the station as "Country", or "Talk Radio", or
whatever, based on what you hear. You'll probably have an
overpowering feeling that if only you could just improve the
S/N a *teeny* bit you would understand everything. But you
can't.

And if you switch the noise source to *both* ears, the
phantom signal vanishes and you just hear noise. (Sometimes
you can get the effect with both ears, but it may take a
*lot* of listening.)

I actually discovered this a long time ago, while designing
a diode-based noise generator. Since that sort of circuit
involves a lot of gain, when I heard the "radio station" I
naturally assumed that's *exactly* what it was hearing. I
tried all kinds of filtering before I finally got rid of
it... coincidentally having switched from a single-ear
lineman's test set to stereo phones. Problem solved!

Then I built a completely digital version, which doesn't
involve gain and is not susceptible to AM pickup... or so I
assumed. Yet it was back again, but only with the mono
headset, not stereo or speakers. Took a lot of testing to
convince myself that it wasn't a circuit problem... at least
not in my hardware circuit, only the "wetware" between my
ears!

Then when I showed the phantom signals effect to others they
were absolutely convinced it was a real radio station, and
that there was some defect in my hardware. Had to go
through all the steps with them to prove it was only in
their heads. The really convincing proof was that it
vanished instantly when heard through both ears... hard to
explain if it was AM pick-up!

For a long time I didn't want to announce this to the
general public because I hoped to recruit subjects for an
unbiased test. But that got put on the back burner for so
long that I've given up on it.

So enjoy!

Best regards,


Bob Masta

DAQARTA v6.02
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!

 

[Oppie]

"Chiron" <chiron613@gmail.com> wrote in message
news:weLYq.15012$Au5.1702@newsfe23.iad...

I need a source of white noise (audio). It doesn't have to be perfect.

I seem to recall that you could use a zener diode as a white noise
source. Is this true? Are there any other possibilities? I anticipate
using a 9-V battery for my power, and a few transistors to amplify the
signal to drive earphones.

You may ask, "why the heck would he want to do that?" Good question:

http://en.wikipedia.org/wiki/Electronic_voice_phenomenon

Since I believe that the chances of there being anything to this are just
about zero, I don't want to invest a whole lot of effort in doing it.

Zeners do work. I had used a 6V zener feeding it through a 1 meg resistor
from 15V. The spectrum was lacking in much of the audio range though. I had
better success reverse biasing the base-emitter junction of any garden
variety transistor. The NPNs that I tried break down in the range of 8
volts, so again, a 1 Meg feed from 15V is a good starting point.

the '15V' can be either from two 9V batteries or a boost converter.

OR you can look up "white noise schematic"

Pseudo Random Noise can be digitally generated with a recirculating shift
register that has the feedback tapped at a few points and XORed as shown in
this diagram
http://www.discovercircuits.com/DJ-Circuits/noisegen.htm
It shows 12V power but modern logic elements will work at lower voltages. I
used a similar circuit for calibrating a sonar system (signal of interest
burried in 90 db of noise).

 

[Chiron]

On Thu, 09 Feb 2012 09:32:55 -0500, Oppie wrote:

<snip>

Thanks, Oppie. I might try the idea with the transistor. Seems like it
might be what I'm looking for...




--
Exercise caution in your daily affairs.

 

[Chiron]

On Thu, 09 Feb 2012 13:28:04 -0800, George Herold wrote:

<snip>

I really like 20V 1/2 watt zeners for this... bias from +/-15 volts
through a 1 meg resistor. Lotsa noise and flat out to ~500kHz or so.
The voltage is a bit asymmetric, but that can be fixed..... by adding
two of opposite polarity.

Thanks, George. Is there anything special about the zener being 20V? In
other words, would a 20V zener be better than using, say, a 5.1V?


--
Tart words make no friends; a spoonful of honey will catch more flies than
a gallon of vinegar.
-- B. Franklin

 

[George Herold]

On Feb 9, 3:13 am, Chiron <chiron...@gmail.com> wrote:

I need a source of white noise (audio).  It doesn't have to be perfect.

I seem to recall that you could use a zener diode as a white noise
source.  Is this true?  Are there any other possibilities?  I anticipate
using a 9-V battery for my power, and a few transistors to amplify the
signal to drive earphones.

You may ask, "why the heck would he want to do that?"  Good question:

http://en.wikipedia.org/wiki/Electronic_voice_phenomenon

Since I believe that the chances of there being anything to this are just
about zero, I don't want to invest a whole lot of effort in doing it.

--
Do not apply to broken skin.

I really like 20V 1/2 watt zeners for this... bias from +/-15 volts
through a 1 meg resistor. Lotsa noise and flat out to ~500kHz or so.
The voltage is a bit asymmetric, but that can be fixed..... by adding
two of opposite polarity.

George H.

 

[BeeJ]

on 2/9/2012, Chiron supposed :

On Thu, 09 Feb 2012 13:28:04 -0800, George Herold wrote:

snip

I really like 20V 1/2 watt zeners for this... bias from +/-15 volts
through a 1 meg resistor. Lotsa noise and flat out to ~500kHz or so.
The voltage is a bit asymmetric, but that can be fixed..... by adding
two of opposite polarity.


Thanks, George. Is there anything special about the zener being 20V? In
other words, would a 20V zener be better than using, say, a 5.1V?

Yes, the higher voltage zeners have a little negative resistance in
part of their curve. That is why you can build an oscillator using
just the diode a capacitor and resistor. Try it. Fun.
Look closely at the curves on the higher voltage zeners.

 

[Chiron]

On Thu, 09 Feb 2012 17:46:23 -0800, George Herold wrote:

Yeah a big difference. In low voltage Zeners the current is from
tunneling electrons (one at a time) and only have shot noise. (Which is
pretty small). High voltage 'Zeners' do this avalanche break down...big
random current pulses.
Lot's more noise 'amplitude'.
I looked at a bunch of different voltages. (Above somethiing like 6V is
where you start to get some avalanching.) 10 and 12 Volt Zeners showed
more than shot noise, but there was a lot of part to part variation in
the amount of noise. For some reason* 20V zeners all give about the
same signal levels... I posted a 'scope shot some time back.
If you use glass encapsulated diodes then wrap some black electrical
tape around them... else the room lights leak in and ruin everthing.

<snip>

This is interesting. Who knew there was so much to something as
(seemingly) simple as a zener diode? Not me, anyway.

Thanks for the info.


--
Afternoon, n.:
That part of the day we spend worrying about how we wasted the
morning.






--
I'm a soldier, not a diplomat. I can only tell the truth.
-- Kirk, "Errand of Mercy", stardate 3198.9

 

[Chiron]

On Thu, 09 Feb 2012 09:32:55 -0500, Oppie wrote:

<snip>

OR you can look up "white noise schematic"

Never even thought of that; I'll do it.

Pseudo Random Noise can be digitally generated with a recirculating
shift register that has the feedback tapped at a few points and XORed as
shown in this diagram
http://www.discovercircuits.com/DJ-Circuits/noisegen.htm It shows 12V
power but modern logic elements will work at lower voltages. I used a
similar circuit for calibrating a sonar system (signal of interest
burried in 90 db of noise).

I think I recall something similar from Don Lancaster's CMOS Cookbook...
but IIRC, the "noise" repeated. Not sure whether that would be a
problem, though...

Anyway, thanks for the ideas.


--
Some of us are becoming the men we wanted to marry.
-- Gloria Steinem

 

[George Herold]

On Feb 9, 9:04 pm, Chiron <chiron...@gmail.com> wrote:

On Thu, 09 Feb 2012 17:46:23 -0800, George Herold wrote:
Yeah a big difference.  In low voltage Zeners the current is from
tunneling electrons (one at a time) and only have shot noise.  (Which is
pretty small).  High voltage 'Zeners' do this avalanche break down...big
random current pulses.
Lot's more noise 'amplitude'.
I looked at a bunch of different voltages.  (Above somethiing like 6V is
where you start to get some avalanching.)  10 and 12 Volt Zeners showed
more than shot noise, but there was a lot of part to part variation in
the amount of noise.  For some reason* 20V zeners all give about the
same signal levels... I posted a 'scope shot some time back.
If you use glass encapsulated diodes then wrap some black electrical
tape around them... else the room lights leak in and ruin everthing.

snip

This is interesting.  Who knew there was so much to something as
(seemingly) simple as a zener diode?  Not me, anyway.

Grin... You caught me at golden moment, I'm waiting for a pcb with a
Zener noise source on it to come back from the board house.

Diodes look simple, but there is lots of nice physics to be got out of
them.
Decent thermometers for instance.

George H.

Thanks for the info.

--
Afternoon, n.:
        That part of the day we spend worrying about how we wasted the
morning.

--
I'm a soldier, not a diplomat.  I can only tell the truth.
                -- Kirk, "Errand of Mercy", stardate 3198..9

 

[George Herold]

On Feb 9, 5:15 pm, Chiron <chiron...@gmail.com> wrote:

On Thu, 09 Feb 2012 13:28:04 -0800, George Herold wrote:

snip



I really like 20V 1/2 watt zeners for this... bias from +/-15 volts
through a 1 meg resistor.  Lotsa noise and flat out to ~500kHz or so.
The voltage is a bit asymmetric, but that can be fixed..... by adding
two of opposite polarity.

Thanks, George.  Is there anything special about the zener being 20V?  In
other words, would a 20V zener be better than using, say, a 5.1V?

--
Tart words make no friends; a spoonful of honey will catch more flies than
a gallon of vinegar.
                -- B. Franklin

Yeah a big difference. In low voltage Zeners the current is from
tunneling electrons (one at a time) and only have shot noise. (Which
is pretty small). High voltage 'Zeners' do this avalanche break
down...big random current pulses.
Lot's more noise 'amplitude'.
I looked at a bunch of different voltages. (Above somethiing like 6V
is where you start to get some avalanching.) 10 and 12 Volt Zeners
showed more than shot noise, but there was a lot of part to part
variation in the amount of noise. For some reason* 20V zeners all
give about the same signal levels... I posted a 'scope shot some time
back.
If you use glass encapsulated diodes then wrap some black electrical
tape around them... else the room lights leak in and ruin everthing.

George H.

* So here's a WAG as to why 20V (or there abouts) has uniform noise
piece to piece.
At lower volatage the break down is at some channel in the diode.
There's a lot of variation in the 'golden' channel for different
diodes. So different sizes of current pulses... (different
capacitances in each channel).

But at some voltage, (20V?) the whole diode breaks down and you get a
current pulse that is the whole diode capacitance. Since this is
pretty constant, you get about the same size of pulses piece to
piece. (I'll mave to 'measure' the pulse size and see if that
fits...)

 

[George Herold]

On Feb 9, 5:36 pm, BeeJ <nos...@spamnot.com> wrote:

on 2/9/2012, Chiron supposed :

On Thu, 09 Feb 2012 13:28:04 -0800, George Herold wrote:

snip

I really like 20V 1/2 watt zeners for this... bias from +/-15 volts
through a 1 meg resistor.  Lotsa noise and flat out to ~500kHz or so..
The voltage is a bit asymmetric, but that can be fixed..... by adding
two of opposite polarity.

Thanks, George.  Is there anything special about the zener being 20V?  In
other words, would a 20V zener be better than using, say, a 5.1V?

Yes,  the higher voltage zeners have a little negative resistance in
part of their curve.  That is why you can build an oscillator using
just the diode a capacitor and resistor.  Try it.  Fun.
Look closely at the curves on the higher voltage zeners.

Interesting, can you post a schematic? It may not be negative
resistance.... With a long enough time constant, you may be seeing the
random 'firing' of the zeners discharging the RC, then waiting a few
RC for the voltage to rise. Once above some 'thershold' you only
have to wait about a micro second till the next random firing.

George H.

 

[Michael Black]

On Fri, 10 Feb 2012, Chiron wrote:

On Thu, 09 Feb 2012 09:32:55 -0500, Oppie wrote:

snip


OR you can look up "white noise schematic"

Never even thought of that; I'll do it.

Pseudo Random Noise can be digitally generated with a recirculating
shift register that has the feedback tapped at a few points and XORed as
shown in this diagram
http://www.discovercircuits.com/DJ-Circuits/noisegen.htm It shows 12V
power but modern logic elements will work at lower voltages. I used a
similar circuit for calibrating a sonar system (signal of interest
burried in 90 db of noise).

I think I recall something similar from Don Lancaster's CMOS Cookbook...
but IIRC, the "noise" repeated. Not sure whether that would be a
problem, though...

It depends on what you want, and how long the sequence is.

Sound generator ICs like the AY-5-8910 (I think I got that number right)
or those from Texas Instruments used that scheme. If the sound generator
in the Commodore 64 included a white noise source (I can't remember), then
it used that scheme.

For a while in the seventies, National Semiconductor had an IC that
generated noise using that scheme, it was sold as a "pink noise
generator", where you'd add an external filter to make the noise "pink".
Another company had a similar device.

Of course, PAIA just used a 2N2712 for the noie source in their projects.
It was never clear if they found that device was better at it, or if they
just found a cheap device.

Michael

 

[Chiron]

On Thu, 09 Feb 2012 22:49:29 -0500, Michael Black wrote:

<snip>

It depends on what you want, and how long the sequence is.

Sound generator ICs like the AY-5-8910 (I think I got that number right)
or those from Texas Instruments used that scheme. If the sound
generator in the Commodore 64 included a white noise source (I can't
remember), then it used that scheme.

For a while in the seventies, National Semiconductor had an IC that
generated noise using that scheme, it was sold as a "pink noise
generator", where you'd add an external filter to make the noise "pink".
Another company had a similar device.

Of course, PAIA just used a 2N2712 for the noie source in their
projects. It was never clear if they found that device was better at it,
or if they just found a cheap device.

Michael

IIRC, the C-64 did have some sort of noise function... we're going back a
ways now. That was about the last time I played around with electronics,
too. Things have changed a wee bit since then - what, 1988 or so?

I found a circuit that looks promising. I'll have to refer you to the
Website, since I don't yet know how to draw schematics using ASCII:

http://www.seekic.com/uploadfile/ic-circuit/2009624223240862.gif

This circuit uses 2 resistors, 2 capacitors, a diode and a 2N3904. I
doubt I'm going to find anything simpler, unless it's an IC like you
described.

I think my main problem was I didn't hit upon the right Google search
words, so I was chasing down all kinds of stuff that had nothing to do
with what I wanted.

Thanks, all, for your help.



--
The profession of book writing makes horse racing seem like a solid,
stable business.
-- John Steinbeck
[Horse racing *is* a stable business ...]

 

On Feb 9, 6:09 am, N0S...@daqarta.com (Bob Masta) wrote:

Download my Daqarta software... it's free for signal
generation use.  Midway down the Generator dialog, click the
left Waveform Controls button. Click Wave on the dialog that
appears and select Noise: White.  Toggle the Generator
button on in the main toolbar.  The first time the Generator
goes on the volume control dialog will pop up, plus a
cautionary message about loud levels.  You'll need to cancel
the message before the sound starts.  (In WinXP you may also
need to unMute, at the bottom of that dialog.)  Later, you
can open the volume dialog via the F9 key at any time.

<snip>

Bob Masta

You give them a solution - and for free that they can use right now -
and they continue to talk about using Zeners to make noise. I have a
horse. I showed him where the water is and he drinks it. Not sure
about these people though.

G˛

 

[Chiron]

On Thu, 09 Feb 2012 21:58:06 -0800, stratus46 wrote:

You give them a solution - and for free that they can use right now -
and they continue to talk about using Zeners to make noise. I have a
horse. I showed him where the water is and he drinks it. Not sure about
these people though.

G²

How about, I ask for a cheeseburger; someone offers me a free glass of
water; but I keep talking about the cheeseburger, because I'm hungry, not
thirsty. Besides, your horse is drinking out of the glass, and that's
just plain gross.

To be honest, I never saw the post you quoted. It didn't get past the
killfile - too many lines. Unfortunately, one of the problems with a
killfile is that you may wind up blocking perfectly legitimate posts, as
you try to get rid of all the crap.

OK, I'll have a look on Google and see what he said...

--
You can always tell luck from ability by its duration.

 

[Chiron]

On Thu, 09 Feb 2012 23:58:58 -0800, stratus46 wrote:

<snip>

You asked for an audio noise source and mentioned Zeners but you have to
build something to actually use Zeners. You obviously have a computer
which very likely has audio capabilities. You can build something in a
few days or you can have your noise source in minutes. You were offered
a noise source. What's your time worth?

G²

Yes, of course you're right. However, there are several considerations
here. First, as I said, I had no idea Bob Masta had responded to my
post- a problem I hope to fix very soon. Second, I don't use Windows,
which is the OS he writes programs for. Third, I do this stuff for fun,
so I have not the slightest objection to reinventing the wheel or doing
things the "hard" way.

The circuit I found contains six parts. If I had the zener I could slap
it together in about ten minutes.

But mostly I just didn't see Bob's post. Even if I didn't like his idea
(and I do like it), I'd have been courteous enough to reply, had I seen
the post.

--
Start the day with a smile. After that you can be your nasty old self
again.






--
When I was 16, I thought there was no hope for my father. By the time I
was
20, he had made great improvement.

 

[chiron613]

On Feb 9, 8:09 am, N0S...@daqarta.com (Bob Masta) wrote:

A whole lot that I missed...

<snip>

Bob, I apologize for not responding to your thoughtful post. I keep a
fairly stringent killfile, and one of the things I filter on is the
length of the post. Unfortunately, the filter doesn't distinguish
between someone endlessly ranting, and someone who has troubled to
write a lengthy response. I'll have to rework the filter somehow to
make sure you don't get blocked again.

Your suggestion to use only a single ear is intriguing, and something
I'd not heard about before. Had you not mentioned it, I'd have used
both earphones; but now I will follow your idea and use only one.

To be honest, I am highly doubtful of this EVP. My guess is that
people, when encountering auditory or visual "noise." tend to perceive
patterns where none exist. Of course, then you get into the question
of whether someone is hearing voices that don't exist, or whether
someone is simply deaf to those voices. An interesting philosophical

 

On Feb 9, 11:44 pm, Chiron <chiron...@gmail.com> wrote:

On Thu, 09 Feb 2012 21:58:06 -0800, stratus46 wrote:
You give them a solution - and for free that they can use right now -
and they continue to talk about using Zeners to make noise. I have a
horse. I showed him where the water is and he drinks it. Not sure about
these people though.

G˛

How about, I ask for a cheeseburger; someone offers me a free glass of
water; but I keep talking about the cheeseburger, because I'm hungry, not
thirsty.  Besides, your horse is drinking out of the glass, and that's
just plain gross.

To be honest, I never saw the post you quoted.  It didn't get past the
killfile - too many lines.  Unfortunately, one of the problems with a
killfile is that you may wind up blocking perfectly legitimate posts, as
you try to get rid of all the crap.

OK, I'll have a look on Google and see what he said...

--
You can always tell luck from ability by its duration.

You asked for an audio noise source and mentioned Zeners but you have
to build something to actually use Zeners. You obviously have a
computer which very likely has audio capabilities. You can build
something in a few days or you can have your noise source in minutes.
You were offered a noise source. What's your time worth?

G˛