field test unit no 001 "model T"

[Aziz]

Anyone solved the riddle?

[Davor]

Nah. I think I'll just wait to see what that is. So far I'm not impressed by the whole PI thing at all, and the only development I can foresee some tangible success is the Tinkerer's rig.

[PATCHES JUNIOR]

Anyone solved the riddle?

Nah, we all gave up. What is the answer?

[hdphilip]

now i'll have to see if it works on the bench.....to know if it's solved

[moodz]

....been working away at the signal chain ... happily I can now say the descrimination and target channels are working at 24 bit sampling with a bandwidth exceeding 1 Mhz and direct sampling of the frontend. Noise floor is down at -140db .. and I have not even applied the SAT yet ... I can extend the bandwidth to 10 Mhz but the effective bits will drop to 16 ..... not bad for sub $100 hardware .

below are spectrum pix of the target and descrim channels .... I cant show waveforms with target and descrim infos as that may give away too much at this "sensitive" time .....the software PI is coming .... and its a race to the bottom.

[Aziz]

Hey Moodz,

looks like you are No 1 candidate to get the WBGB technology. 1 MHz bandwidth is by far enough.

Direct sampling & decoding is the way to go. Get a high number cruncher for this purpose (DSP).
Cheers,
Aziz

PS: Ooops, forgot something:
It's the end of <you know who>!!!

[Aziz]

And I hope, you drive the ADC-chip in a fully differential mode (differential coil would make sense). That would give a superior SNR.

And I think, you could implement some advanced techniques to reduce further noise. Make sure, your platform has enough RAM memory and CPU/FPU processing power.

Aziz


PS: Get ready to get legally sued to be better than <YKW>.
*LOL*

[chudster]

..been working ..away at the signal chain ... happily I can now say the descrimination and target channels are working at 24 bit sampling with a bandwidth exceeding 1 Mhz and direct sampling of the frontend. Noise floor is down at -140db .. and I have not even applied the SAT yet ... I can extend the bandwidth to 10 Mhz but the effective bits will drop to 16 ..... not bad for sub $100 hardware .

below are spectrum pix of the target and descrim channels .... I cant show waveforms with target and descrim infos as that may give away too much at this "sensitive" time .....the software PI is coming .... and its a race to the bottom.

[ATTACH]21352[/ATTACH]
[ATTACH]21353[/ATTACH]

Moodz,

Are you saying that you are sampling 24 bits at 2MSPS to get a bandwidth of 1 MHz or is this of the demodded signal at a lower sample rate?

Chudster

[moodz]

And I hope, you drive the ADC-chip in a fully differential mode (differential coil would make sense). That would give a superior SNR.

And I think, you could implement some advanced techniques to reduce further noise. Make sure, your platform has enough RAM memory and CPU/FPU processing power.

Aziz


PS: Get ready to get legally sued to be better than <YKW>.
*LOL*

Fully differential and DC accurate ... max input is +/- 2.5 volts to the ADC channels ..

[Aziz]

He is sampling at 2.5 MHz according to the FFT spectrum.

[Aziz]

Fully differential and DC accurate ... max input is +/- 2.5 volts to the ADC channels ..

BRAVO!!!! I like it.
Forget my projects. The QED2 will be a killer-app. That's a game changer.
(And I can give you a lot of high-tech info as well (WBGB, noise elimination, etc..))
Aziz

[moodz]

This is direct sampled at 2 msps ... I can sample up to 20 msps but the effective bits will drop to 16 and noise floor to around -80 db ...Lots of testing to do .... LOL .... but now I dont have to tweak hardware .... only software. I am expecting to pick up another 6 bits of effective resolution on top of the 24 bit which together with the "new" front end and adaptive ground balance is going to be a very good system. The overall "real" bit resolution is slightly north of 26 bits and a system gain of around 10,000,000 over a 10 Hz bandwidth. ( ie approx 1000 times better than a 16 bit system ... taking into consideration system noise and processing gain).

[moodz]

BRAVO!!!! I like it.
Forget my projects. The QED2 will be a killer-app. That's a game changer.
(And I can give you a lot of high-tech info as well (WBGB, noise elimination, etc..))
Aziz

Aziz ... dont forget your projects ... I am working on a "front end" for you to play with ... it will have a multi channel 24 bit adc / dac with no bandwith limiting and access to DSP functions then piping to laptop / whatever through USB.

[Aziz]

Hey Moodz,

do you use a DMA interface for the ADC? It would make heavily sense, rather than bit-banging the ADC interface.
Aziz

[Aziz]

Aziz ... dont forget your projects ... I am working on a "front end" for you to play with ... it will have a multi channel 24 bit adc / dac with no bandwith limiting and access to DSP functions then piping to laptop / whatever through USB.

Yeah, fantastic!!!

I like the USB interfacing feature... Tablet PC is coming...yeah!
Aziz