6V White Noise Circuit

[Leo Kemp]

Does anyone know of an analog circuit that will generate white noise
from a 6V rail?

This appears to be too low for the conventional back-biased junction
approach.

Please correct me if I am wrong.

What are the alternatives?

Leo Kemp

 

[Joerg]

Digital pseudo-random is nice.

Photocoupler shot noise.

A 5 volt zener plus amplifiers should be pretty noisy.

Amplify Johnson noise, plus an opamp's input current noise.

Just use a noisy opamp.

Let me throw another one into the hat: A small hot filament, as in light
bulb.

Leo, if you already have a good noise source you are familiar with and
it requires more than 6V, why not step up the voltage? A little boost
regulator maybe? Or a gate driver with Schmitt input running as an
oscillator, followed by a Cockroft-Walton style doubler which should net
you around 10VDC.

[...]

 

[Leo Kemp]

Use an RF transistor such as MPSH-10 the breakdown voltage is 3v (typ)
as opposed to the GP transistor 5v (typ)

This seems to be the tidiest solution, keeping in mind my OP stating
"analog".

We would need to order these in. Can anyone confirm this will work
from experience?

Leo

 

[Leo Kemp]

The transistor will produce much more noise than the zener. Manufacturers
have worked to reduce the noise from the zener, not so for the transistor.
The MPSH-10 costs 12 cents in one-offs from futurelec

Yes, I tried the zener idea. No Go. The amp produced more noise. I
will try an RF transistor next.

Have done digital noise gen before, but the parts count was too high
for my app.

I do recall one manufacturer producing a dedicated white noise IC, but
I understood it is no longer available.

Leo

 

[John S]

Yes, I tried the zener idea. No Go. The amp produced more noise. I
will try an RF transistor next.

Have done digital noise gen before, but the parts count was too high
for my app.

I do recall one manufacturer producing a dedicated white noise IC, but
I understood it is no longer available.

Leo

Try these guys:

http://noisecom.com/products/components

 

[josephkk]

The right sort of scrambler could increase the run length.

John

Maybe, maybe not. While i am not totally ignorant of such math i suspect
i would struggle with a proof either way. I still want to get ahold of
Dr. Golds paper on maximally orthogonal PRN codes.

?-)