Where to get high speed ADC's and DACs

[RobertMacy]

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

 

[Lasse Langwadt Christense]

On Sunday, September 1, 2013 9:39:41 PM UTC+2, DecadentLinuxUserNumeroUno wrote:

On Sun, 01 Sep 2013 22:21:15 +0300, upsidedown@downunder.com Gave us:



On Sun, 01 Sep 2013 10:45:34 -0700, RobertMacy

robert.a.macy@gmail.com> wrote:



On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin

jjlarkin@highnotlandthistechnologypart.com> wrote:



On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com

wrote:



Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?



Or, turn around how much digitization can I get out to 100MHz today? 20

bits?



This is about right:



http://www.linear.com/designtools/hsadcs.php





We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.



https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg



A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise

would

trash a lot of LSBs.









John,



You have no idea how much I respect Linear and their products. but I was

talking about 20+bits not the insignificant 12 bit range.



At least a few years ago getting 120 dB SNR with 20 kHz audio

bandwidth was quite normal (20 bits at 50 kHz) or in scales getting 24

bits with 1-2 samples/second.



[I recently did 18 bits at 500MHz - Jim Williams would have been proud,

NEVER AGAIN!!!



From simulations, I need 20+ bits, else quantization noise eats me alive!



Is adding dithering noise out of the question ?



Look into what GPS receivers use.



They are the lowest level signals we discriminate currently. They

reside just above the noise floor. At -127.5 dBm.



But that is a receiver signal value, not an ADC SNL function.

Still, one might find some pointers by examining what those folks do.

GPS only use a few bits of adc if not only one bit ...



-Lasse

 

[John Larkin]

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com> wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise would
trash a lot of LSBs.



--

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

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[Lasse Langwadt Christense]

On Sunday, September 1, 2013 6:33:15 PM UTC+2, Robert Macy wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?



Or, turn around how much digitization can I get out to 100MHz today? 20

bits?

analog has 16bits at 250MHz http://www.analog.com/en/analog-to-digital-converters/ad-converters/ad9467/products/product.html


-Lasse

 

[Phil Hobbs]

On 9/1/2013 12:33 PM, RobertMacy wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

Sure thing. Just use two 10-bit ADCs and put a 60 dB pad in front of
one of them.

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 USA
+1 845 480 2058

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

 

[John Larkin]

On Sun, 01 Sep 2013 13:23:55 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 9/1/2013 12:33 PM, RobertMacy wrote:
Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

Sure thing. Just use two 10-bit ADCs and put a 60 dB pad in front of
one of them.

Cheers

Phil Hobbs

It's cheaper to concatenate the output of a 10-bit ADC with a 10-bit random
sequence generator.


--

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

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[RobertMacy]

On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin
<jjlarkin@highnotlandthistechnologypart.com> wrote:

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com
wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise
would
trash a lot of LSBs.

John,

You have no idea how much I respect Linear and their products. but I was
talking about 20+bits not the insignificant 12 bit range.

[I recently did 18 bits at 500MHz - Jim Williams would have been proud,
NEVER AGAIN!!!

From simulations, I need 20+ bits, else quantization noise eats me alive!

 

[RobertMacy]

On Sun, 01 Sep 2013 10:23:55 -0700, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 9/1/2013 12:33 PM, RobertMacy wrote:
Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

Sure thing. Just use two 10-bit ADCs and put a 60 dB pad in front of
one of them.

Cheers

Phil Hobbs

PHIL! Not funny! well maybe, a bit, still LOL

 

[Phil Hobbs]

On 9/1/2013 1:47 PM, RobertMacy wrote:

On Sun, 01 Sep 2013 10:23:55 -0700, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 9/1/2013 12:33 PM, RobertMacy wrote:
Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

Sure thing. Just use two 10-bit ADCs and put a 60 dB pad in front of
one of them.

Cheers

Phil Hobbs


PHIL! Not funny! well maybe, a bit, still LOL

Well, if we generously assume that an ADC that fast could have a 5V
input range, 1 LSB at 20 bits is 5 uV, and the quantization noise is
1/sqrt(12) times that, or 1.4 uV. In a 100 MHz bandwidth, that's
140 pV/sqrt(Hz). In real life, the input structure would have to be
several times faster than that in order to settle to that accuracy in
the time available, putting the maximum input noise down in the
50 pV/sqrt(Hz) range, not counting the effects of input capacitance.

Good luck with that.

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 USA
+1 845 480 2058

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

 

[Jim Thompson]

On Sun, 01 Sep 2013 13:23:55 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 9/1/2013 12:33 PM, RobertMacy wrote:
Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

Sure thing. Just use two 10-bit ADCs and put a 60 dB pad in front of
one of them.

Cheers

Phil Hobbs

But not nearly as sexy.

Way back in the design days for the L1011, I suggested a seat-audio
system made up of two 8-bit DAC's, one basically volume riding, and
the other the "detail".

Demonstrated it. Sounded great. Rejected in spite of how inexpensive
it was. They went with a much more expensive 12-bit DAC.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Vladimir Vassilevsky]

On 9/1/2013 11:33 AM, RobertMacy wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?
Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

You can get true 24 bit performance in a bandwidth of somewhat like 50Hz
(current state of art).
For 100 MHz bandwidth, you just have to parrallel 2000000 frequency
split channels.


VLV

 

[RobertMacy]

On Sun, 01 Sep 2013 11:20:55 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

..snip...
Way back in the design days for the L1011, I suggested a seat-audio
system made up of two 8-bit DAC's, one basically volume riding, and
the other the "detail".

Demonstrated it. Sounded great. Rejected in spite of how inexpensive
it was. They went with a much more expensive 12-bit DAC.

...Jim Thompson

Don't get me started on 'closed mindedness'!

Back around 1966, I designed the hardware computer interface for L1011.
Going from that environment [aerospace and autopilots] to HP' RF/Microwave
Lab, noted for their conservative designs, was like being thrust into the
sloppiest garage designers I'd ever seen! Imagine what it was like to go
from that into coin-opeated electronic games!

 

[RobertMacy]

On Sun, 01 Sep 2013 11:29:53 -0700, Vladimir Vassilevsky
<nospam@nowhere.com> wrote:

On 9/1/2013 11:33 AM, RobertMacy wrote:
Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?
Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

You can get true 24 bit performance in a bandwidth of somewhat like 50Hz
(current state of art).
For 100 MHz bandwidth, you just have to parrallel 2000000 frequency
split channels.


VLV

Vladimir,

I know your answer was 'tongue in cheek' but you actually have made me
think about directions/concepts that had NOT occurred to me before. Thanks.

Interesting about that bandwidth. TI makes a 24 bit seismic ADC [ADS1282?]
that just about has that bandwidth. Give me an email address and I'll send
you an example of using a PCB Layout Tool I created for checking PCB Plane
noise around uP, etc and ADC. I used the tool to check the efficacy of a
'first pass' PCB layout design using that chip. The tool showed were
better than 1/4 LSB noise.

 

[Phil Hobbs]

On 9/1/2013 2:35 PM, RobertMacy wrote:

On Sun, 01 Sep 2013 11:20:55 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

..snip...
Way back in the design days for the L1011, I suggested a seat-audio
system made up of two 8-bit DAC's, one basically volume riding, and
the other the "detail".

Demonstrated it. Sounded great. Rejected in spite of how inexpensive
it was. They went with a much more expensive 12-bit DAC.

...Jim Thompson

Don't get me started on 'closed mindedness'!

Back around 1966, I designed the hardware computer interface for L1011.
Going from that environment [aerospace and autopilots] to HP'
RF/Microwave Lab, noted for their conservative designs, was like being
thrust into the sloppiest garage designers I'd ever seen! Imagine what
it was like to go from that into coin-opeated electronic games!

I remember vividly the experience of pitching Footprints(*) to a major
manufacturer of commercial control systems. (You'd recognize the name
instantly.)

At the time, they were buying 256-pixel IR sensors for $4000 apiece,
which weren't as good as my $100 ones. We pitched it like this:

"You're paying $4k * 1000 units = $4M per year now. Our technology will
cost you $100 per unit plus a $50 royalty, i.e. $150k per year."

What we expected them to say:
"Wow, we can save $3.85M per year! Let's buy a house in Aruba!

What they actually said:
"That's a FIFTY PERCENT ROYALTY! Are you out of your MIND?"

A classical example of inside-the-box thinking, as I later realized. I'd
led a very sheltered life up to then, and had never really encountered
it before.

Cheers

Phil Hobbs

(*) Footprints was a distributed system of $10-ish IR imagers with
$50-ish back ends, about $100 installed.
See http://electrooptical.net/#footprints .


--
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 USA
+1 845 480 2058

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

 

On Sun, 01 Sep 2013 10:45:34 -0700, RobertMacy
<robert.a.macy@gmail.com> wrote:

On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin
jjlarkin@highnotlandthistechnologypart.com> wrote:

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com
wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise
would
trash a lot of LSBs.




John,

You have no idea how much I respect Linear and their products. but I was
talking about 20+bits not the insignificant 12 bit range.

At least a few years ago getting 120 dB SNR with 20 kHz audio
bandwidth was quite normal (20 bits at 50 kHz) or in scales getting 24
bits with 1-2 samples/second.

[I recently did 18 bits at 500MHz - Jim Williams would have been proud,
NEVER AGAIN!!!

From simulations, I need 20+ bits, else quantization noise eats me alive!

Is adding dithering noise out of the question ?

 

[DecadentLinuxUserNumeroUn]

On Sun, 01 Sep 2013 22:21:15 +0300, upsidedown@downunder.com Gave us:

On Sun, 01 Sep 2013 10:45:34 -0700, RobertMacy
robert.a.macy@gmail.com> wrote:

On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin
jjlarkin@highnotlandthistechnologypart.com> wrote:

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com
wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise
would
trash a lot of LSBs.




John,

You have no idea how much I respect Linear and their products. but I was
talking about 20+bits not the insignificant 12 bit range.

At least a few years ago getting 120 dB SNR with 20 kHz audio
bandwidth was quite normal (20 bits at 50 kHz) or in scales getting 24
bits with 1-2 samples/second.

[I recently did 18 bits at 500MHz - Jim Williams would have been proud,
NEVER AGAIN!!!

From simulations, I need 20+ bits, else quantization noise eats me alive!

Is adding dithering noise out of the question ?

Look into what GPS receivers use.

They are the lowest level signals we discriminate currently. They
reside just above the noise floor. At -127.5 dBm.

But that is a receiver signal value, not an ADC SNL function.
Still, one might find some pointers by examining what those folks do.

 

On Sun, 01 Sep 2013 12:39:41 -0700, DecadentLinuxUserNumeroUno
<DLU1@DecadentLinuxUser.org> wrote:

On Sun, 01 Sep 2013 22:21:15 +0300, upsidedown@downunder.com Gave us:

On Sun, 01 Sep 2013 10:45:34 -0700, RobertMacy
robert.a.macy@gmail.com> wrote:

On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin
jjlarkin@highnotlandthistechnologypart.com> wrote:

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com
wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise
would
trash a lot of LSBs.




John,

You have no idea how much I respect Linear and their products. but I was
talking about 20+bits not the insignificant 12 bit range.

At least a few years ago getting 120 dB SNR with 20 kHz audio
bandwidth was quite normal (20 bits at 50 kHz) or in scales getting 24
bits with 1-2 samples/second.

[I recently did 18 bits at 500MHz - Jim Williams would have been proud,
NEVER AGAIN!!!

From simulations, I need 20+ bits, else quantization noise eats me alive!

Is adding dithering noise out of the question ?

Look into what GPS receivers use.

They are the lowest level signals we discriminate currently. They
reside just above the noise floor. At -127.5 dBm.

I guess that I am responding to a troll, but anyway.

With a primitive antenna, it will see partly the "warm" earth at 300 K
as well as the cold sky 3 K (cosmic background radiation). Assuming
worst case 300 K antenna temperature, this corresponds to -174 dBm/Hz.
The GPS data telegrams (such as the almanak) are transimtted at 50
bit/s data rate, thus someting like -157 dBm is required.

The PRN 1000 Hz signal repetition sequence would suggest 1 kHz
bandwidth and -144 dBm signal levels.

Considering the 1.023 MHz chip rate and similar bandwidths, the needed
signal is about -117 dBm.

I have no real understanding, what -127.5 dBm might mean ?

For an unknown startup location and no bit sync, that would be a good
figure. For synchronized data extraction at -127 dBm that would be
quite bad.

 

[John Larkin]

On Sun, 01 Sep 2013 10:45:34 -0700, RobertMacy <robert.a.macy@gmail.com> wrote:

On Sun, 01 Sep 2013 09:44:40 -0700, John Larkin
jjlarkin@highnotlandthistechnologypart.com> wrote:

On Sun, 01 Sep 2013 09:33:15 -0700, RobertMacy <robert.a.macy@gmail.com
wrote:

Where do I get 24 bit high speed ADC and DAC systems out to 10MHz?

Or, turn around how much digitization can I get out to 100MHz today? 20
bits?

This is about right:

http://www.linear.com/designtools/hsadcs.php


We use their 250 MHz, 12-bit LVDS ADC and it's pretty good.

https://dl.dropboxusercontent.com/u/53724080/PCBs/ESM_rev_B.jpg

A 20 or 24-bit ADC, at 100 MHz, probably isn't useful. Wideband noise
would
trash a lot of LSBs.




John,

You have no idea how much I respect Linear and their products. but I was
talking about 20+bits not the insignificant 12 bit range.

They have 16 bits at 185 Ms/s.

[I recently did 18 bits at 500MHz - Jim Williams would have been proud,
NEVER AGAIN!!!

From simulations, I need 20+ bits, else quantization noise eats me alive!

At 500 MHz bandwidth (reasonable s/h bw for a 500 Ms/s ADC) a 50 ohm resistor
makes 20 uV RMS Johnson noise, and I doubt that any actual front-end amp will be
anywhere close to that, probably several times worse. Seems to me that you'll
have many LSBs of noise, which may be OK if downstream processing is essentially
narrowband, like some RF stuff.


--

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

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[John Larkin]

On Sun, 01 Sep 2013 14:55:21 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 9/1/2013 2:35 PM, RobertMacy wrote:
On Sun, 01 Sep 2013 11:20:55 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

..snip...
Way back in the design days for the L1011, I suggested a seat-audio
system made up of two 8-bit DAC's, one basically volume riding, and
the other the "detail".

Demonstrated it. Sounded great. Rejected in spite of how inexpensive
it was. They went with a much more expensive 12-bit DAC.

...Jim Thompson

Don't get me started on 'closed mindedness'!

Back around 1966, I designed the hardware computer interface for L1011.
Going from that environment [aerospace and autopilots] to HP'
RF/Microwave Lab, noted for their conservative designs, was like being
thrust into the sloppiest garage designers I'd ever seen! Imagine what
it was like to go from that into coin-opeated electronic games!

I remember vividly the experience of pitching Footprints(*) to a major
manufacturer of commercial control systems. (You'd recognize the name
instantly.)

At the time, they were buying 256-pixel IR sensors for $4000 apiece,
which weren't as good as my $100 ones. We pitched it like this:

"You're paying $4k * 1000 units = $4M per year now. Our technology will
cost you $100 per unit plus a $50 royalty, i.e. $150k per year."

What we expected them to say:
"Wow, we can save $3.85M per year! Let's buy a house in Aruba!

What they actually said:
"That's a FIFTY PERCENT ROYALTY! Are you out of your MIND?"

A classical example of inside-the-box thinking, as I later realized. I'd
led a very sheltered life up to then, and had never really encountered
it before.

Cheers

Phil Hobbs

(*) Footprints was a distributed system of $10-ish IR imagers with
$50-ish back ends, about $100 installed.
See http://electrooptical.net/#footprints .

I made Metricom an offer to save them about $20 per electrical meter, for a $1
royalty. They said "no, but how would you like to be a consultant?"

I'm still here, and they aren't.

I also designed some slick multichannel electric survey meters for Synergistic
Control Systems, for a 15% royalty. They sold thousands, and hired a design
house to get rid of me, and dumped over a megabuck for nothing useful. They're
gone, too.


--

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

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[DecadentLinuxUserNumeroUn]

On Sun, 1 Sep 2013 13:43:25 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> Gave us:

On Sunday, September 1, 2013 9:39:41 PM UTC+2, DecadentLinuxUserNumeroUno wrote:
On Sun, 01 Sep 2013 22:21:15 +0300, upsidedown@downunder.com Gave us:


Look into what GPS receivers use.



They are the lowest level signals we discriminate currently. They

reside just above the noise floor. At -127.5 dBm.



But that is a receiver signal value, not an ADC SNL function.

Still, one might find some pointers by examining what those folks do.

GPS only use a few bits of adc if not only one bit ...

One *still* must pull that bit out of the noise... correctly,
continually.