Wide Band Noise Source

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

 

[Bill Sloman]

On Monday, 10 February 2014 12:44:23 UTC+11, mhend...@unitrans.com wrote:

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?
I don't care if it is flat, or other expensive things, so long as it
is of sufficient strength for equipment testing.

If you aren't too picky, a pseudo-random sequence generator built with a ECLinPS shift register and an ECLinPS exclusive-OR should get up to a GHz or so. The clock oscillator might be interesting. John Larkin plays with that sort of stuff.

Horowitz and Hill's "The Art of Electronics" from section9.33 to the end of the chapter 9 gives chapter and verse. Using a sinc x (sine x/x) weighted resistor sequence to make FIR filter is covered. When I did that - a year or so before the book was published - I found out the hard way that you have to apply a Hamming window to your sinc x values to avoid Gibbs oscillations - ripple - on the low-pass filter profile.

--
Bill Sloman, Sydney

 

[Jeff Liebermann]

On Sun, 09 Feb 2014 21:34:22 -0500, Neon John <no@never.com> wrote:

http://www.google.com/patents/US2942204
HP had this device in their catalog for years.

You beat me to it. That's what I was going to suggest. Grumble.

I built various fluorescent tube based RF noise source over the years.
The microwave variety were stuffed into waveguides. The lower
frequencies were pickup coils (or foil capacitors) wrapped around the
tube with amplifiers of varying denomination for isolation. No need
for waveguide. I just wrapped it in aluminum foil shielding.

More on the topic:
<http://www3.alcatel-lucent.com/bstj/vol28-1949/articles/bstj28-4-608.pdf>
My favored tube was the small 6 inch, T-5, 4 watt, tube, running on
about 100V of DC. There are also smaller CCFL (cold cathode
fluorescent) tubes used for LCD backlighting, which might work, but I
haven't tried them yet.
<http://en.wikipedia.org/wiki/Fluorescent_lamp_formats>

Still more:
<http://ko4bb.com/dokuwiki/doku.php?id=ham_radio:noise_sources_and_noise_figure_measurements>
or look at what others are doing for making noise:
<http://ham-radio.com/k6sti/nsrc.htm>
<http://www.ham-radio.com/sbms/sd/nfsource.htm>
<https://www.google.com/search?q=rf+noise+source&tbm=isch>
Most of these zener diode or reversed BE junction noise generators
will belch something that looks like noise to at least 1GHz, but don't
do well much beyond that.

If you have money:
<http://www.noisecom.com>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

A 50 ohm resistor feeding into a few cascaded MAR-x MMICs ?

Of course you need to shield the resistor and first stages very well
to avoid external signal intrusion.

 

[Jeff Liebermann]

On Sun, 09 Feb 2014 19:52:35 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

Most of these zener diode or reversed BE junction noise generators
will belch something that looks like noise to at least 1GHz, but don't
do well much beyond that.

6.8v zener driving a MMIC product. Scroll down to:
"N-gen Wideband Noise Generator. (100 kHz - 500 MHz)"
<http://www.elecraft.com/mini_module_kits/mini_modules.htm>
Schematic:
<http://www.elecraft.com/manual/E740057_N-Gen_Manual_Rev_D.pdf>
If you replace the MAR-1 with something that works up into the "low
GHz" region, it should be suitable. About $60 for the kit.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[John Larkin]

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

For low level stuff, just a resistor. A 50 ohm resistor makes about 1 nV/rootHz
at room temperature.

More noise, people generally use a "noise diode" which is just a selected zener
diode. A 10 volt zener biased to a few mA will make something like 300 nV/rtHz.
Bandwidth depends on junction capacitance and dynamic impedance.

Photodiodes are nice noise sources, because the Johnson and shot noise levels
are predictable.

People used to use gas discharge tubes in waveguides to make microwave noise;
don't know if they still do.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation

 

[John Larkin]

On Sun, 09 Feb 2014 18:23:45 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:


I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

For low level stuff, just a resistor. A 50 ohm resistor makes about 1 nV/rootHz
at room temperature.

More noise, people generally use a "noise diode" which is just a selected zener
diode. A 10 volt zener biased to a few mA will make something like 300 nV/rtHz.
Bandwidth depends on junction capacitance and dynamic impedance.

Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.




--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation

 

[Neon John]

Here you go:

http://www.google.com/patents/US2942204

HP had this device in their catalog for years.

John

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address

 

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

If you do, please let us know how it turns out. Sounds like a tidy
solution.

Mark Henderson

 

This looks like an interesting option. Designed for continuous
operation and rated at 7W. Price is right.

http://www.ebay.com.au/itm/121270618857?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Mark Henderson.

 

[Phil Hobbs]

On 2/9/2014 9:23 PM, John Larkin wrote:

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:


I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

For low level stuff, just a resistor. A 50 ohm resistor makes about 1 nV/rootHz
at room temperature.

More noise, people generally use a "noise diode" which is just a selected zener
diode. A 10 volt zener biased to a few mA will make something like 300 nV/rtHz.
Bandwidth depends on junction capacitance and dynamic impedance.

Photodiodes are nice noise sources, because the Johnson and shot noise levels
are predictable.

For low noise stuff, I expect that you can do a lot worse than a Tek
SD-42 plugin with ~ 1 mA of photocurrent. DC-6.4 GHz, pretty accurately
known frequency response, no impedance mismatch funnies when you switch
the source, NF of 0 dB dark, 3 dB with light.

I'll have to give that a whirl myself. Lots easier than LN2.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[John Fields]

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

 

[John Larkin]

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com>
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation

 

[John Fields]

On Mon, 10 Feb 2014 09:14:16 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.

---
http://www.youtube.com/watch?v=Oi84maqHgxg

 

[amdx]

On 2/10/2014 11:14 AM, John Larkin wrote:

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.


Johnny! Stop that.

 

[Phil Hobbs]

On 02/10/2014 02:57 PM, John Fields wrote:

On Mon, 10 Feb 2014 09:14:16 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.

---
http://www.youtube.com/watch?v=Oi84maqHgxg

There's a 22 GHz spectrum analyzer on my bench (or it would be if I
could lift it out of the rack). Cost $960 plus shipping. Even mutts
can afford that.

Cheers

Phil "Not a dog person" Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[amdx]

On 2/10/2014 1:55 AM, mhenderson@unitrans.com wrote:

This looks like an interesting option. Designed for continuous
operation and rated at 7W. Price is right.

http://www.ebay.com.au/itm/121270618857?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Mark Henderson.

I bought the lower power version two years ago. Works fine. The price
has dropped in half since I bought mine. I ran into Mr. Ramsey of Ramsey
electronics at a hamfest this weekend. I was introduced when
I made a negative comment about one of the Ramsey FM kits, while
discussing FM transmitters. :-{ oops!
During the conversation, I said I was using a lowpass filter on one
of the CZH transmitters, he said that won't help they have in band spurs.
Mikek

 

[John Larkin]

On Mon, 10 Feb 2014 15:21:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 02/10/2014 02:57 PM, John Fields wrote:
On Mon, 10 Feb 2014 09:14:16 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.

---
http://www.youtube.com/watch?v=Oi84maqHgxg


There's a 22 GHz spectrum analyzer on my bench (or it would be if I
could lift it out of the rack). Cost $960 plus shipping. Even mutts
can afford that.

Cheers

Phil "Not a dog person" Hobbs

The Rigol DSA815 looks pretty good. About $1300, and you can lift it
with one hand. The tracking generator is $200 more, pretty good price
for a 1.5 GHz signal generator.

Rigol make pretty nice gear.



--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Phil Hobbs]

On 02/10/2014 04:32 PM, John Larkin wrote:

On Mon, 10 Feb 2014 15:21:26 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 02/10/2014 02:57 PM, John Fields wrote:
On Mon, 10 Feb 2014 09:14:16 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 10 Feb 2014 11:01:49 -0600, John Fields <jfields@austininstruments.com
wrote:

On Sun, 09 Feb 2014 18:28:37 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:


Oh, zenering the b-e junction of a microwave transistor will probably make
wideband noise. Regular zener diodes have a lot of capacitance.

Hmmm, there's a 3 GHz spectrum analyzer on my bench just now. Maybe I'll try it.

---
I've got some good stuff.
You should really envy me
and pine for my 'gift'.

John Fields

I work in an electronics engineering company. We have test equipment. Nothing
unusual about that.

---
http://www.youtube.com/watch?v=Oi84maqHgxg


There's a 22 GHz spectrum analyzer on my bench (or it would be if I
could lift it out of the rack). Cost $960 plus shipping. Even mutts
can afford that.

Cheers

Phil "Not a dog person" Hobbs

The Rigol DSA815 looks pretty good. About $1300, and you can lift it
with one hand. The tracking generator is $200 more, pretty good price
for a 1.5 GHz signal generator.

Rigol make pretty nice gear.

All the SDR-type analyzers have really crappy phase noise compared to a
YIG-tuned boat anchor, though. Like 30 dB crappier below 10 kHz offset.

If I were doing RF installation work, I'd probably get one, but since
I'm rarely more than ten feet from my rack, there's not much incentive
to compromise.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[John Larkin]

On Mon, 10 Feb 2014 12:44:23 +1100, mhenderson@unitrans.com wrote:

I have seen plenty of published circuits for audio frequency
white/pink noise generators.

What is involved in producing noise up into the low GHz region?

I don't care if it is flat, or other expensive things, so long as it
is of sufficent strength for equipment testing.

Mark Henderson

Here's a BFT25 b-e junction as a zener. Zener voltage is 5.2 at 1 mA,
and the noise level looks best at about 1 mA.

https://dl.dropboxusercontent.com/u/53724080/Noise/BFT25_zener_noise.zip

Looks like about 25 nV/rootHz. Mediocre.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com