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PC Oscilloscope ... getting better

F

Francesco Poderico

Jan 1, 1970
0
Hi all,
a few months ago I started to design and build my own oscilloscope...and in this groups I had a lot of help in solving some problem...

http://thefpproject01.blogspot.co.uk/

I'm getting so excited now... and surprise at same time... how things are getting better and better.
The oscilloscope is now very useful indeed, I have added the capability to see the spectrum, and it works really well.

I still have a long way to go... but it looks promising. please see the picture on my blog.

I'm starting thinking at the next prototype now...
shall I go for a 200 MHz + 64 KRAM ( which I can put on the market for less that 200 pounds cheap oscilloscope but does what it says...) or shall I prototype a 1GSPS? and have a larger margin?
Any suggestions is welcome.

Thanks,
Francesco
 
B

brent

Jan 1, 1970
0
Hi all,
a few months ago I started to design and build my own oscilloscope...and in this groups I had a lot of help in solving some problem...

http://thefpproject01.blogspot.co.uk/

I'm getting so excited now... and surprise at same time... how things aregetting better and better.
The oscilloscope is now very useful indeed, I have added the capability to see the spectrum, and it works really well.

I still have a long way to go... but it looks promising. please see the picture on my blog.

I'm starting thinking at the next prototype now...
shall I go for a 200 MHz + 64 KRAM  ( which I can put on the market forless that 200 pounds cheap oscilloscope but does what it says...) or shallI prototype a 1GSPS? and have a larger margin?
Any suggestions is welcome.

Thanks,
Francesco

You are doing great work!
 
J

John Devereux

Jan 1, 1970
0
Jan Panteltje said:

Yes, yes, nice... but Francesco is already doing 100MSPS and making good
progress towards more it looks like.
I do not even need a micro-processor for TV:
http://127.0.0.1/panteltje/scope_tv/index.html

I remember doing that, sort of, when I was a teenager with my first
scope. Not very good though, did not know how to do the syncs properly,
had to just adjust the frequency and hope it locked somehow.

Was still cool to see!
Just wrote a GPS NMEA parser in PIC 18F asm in 5726 bytes,,
position, speed, heading, altitude.

And I did that with the PIC, programmer, and GPS in a different place,
all remote via ssh -Y from the laptop.
Zero crashes, else I would have had to go there to power cycle....

So proud of myself, can still do it :)


root@raspberrypi:~/compile/pantel/gps_pic# jppp18pi -i gps.hex -e -p -Y
Loading hex file:
Program 5726 bytes at address 0x000000
[...]

Your turn

The only thing comparable to your scope recently was a lashed-up 120MHz
STM32F205 microcontroller running a 2MHz 12 bit external ADC.

During testing I captured the sample buffer with gdb, dumped it through
a little python script I found that fed it into gnuplot. Ended up with
some really nice, true 12 bit high-resolution plots of various
waveforms. Could make a beautiful low frequency scope like that, maybe
with a really high resolution screen like the high end ultrabooks
use. Job for my pi perhaps?
 
R

rickman

Jan 1, 1970
0
Hi all,
a few months ago I started to design and build my own oscilloscope...and in this groups I had a lot of help in solving some problem...

http://thefpproject01.blogspot.co.uk/

I'm getting so excited now... and surprise at same time... how things are getting better and better.
The oscilloscope is now very useful indeed, I have added the capability to see the spectrum, and it works really well.

I still have a long way to go... but it looks promising. please see the picture on my blog.

I'm starting thinking at the next prototype now...
shall I go for a 200 MHz + 64 KRAM ( which I can put on the market for less that 200 pounds cheap oscilloscope but does what it says...) or shall I prototype a 1GSPS? and have a larger margin?
Any suggestions is welcome.

You seem to be doing good work. Is your spec of 5 mV/div really valid?
That would be pretty nice. Most of the low cost scopes don't do so
well on sensitivity.
 
J

josephkk

Jan 1, 1970
0
Hi all,
a few months ago I started to design and build my own oscilloscope...andin this groups I had a lot of help in solving some problem...

http://thefpproject01.blogspot.co.uk/

I'm getting so excited now... and surprise at same time... how things are getting better and better.
The oscilloscope is now very useful indeed, I have added the capability to see the spectrum, and it works really well.

I still have a long way to go... but it looks promising. please see the picture on my blog.

I'm starting thinking at the next prototype now...
shall I go for a 200 MHz + 64 KRAM ( which I can put on the market for less that 200 pounds cheap oscilloscope but does what it says...) or shall I prototype a 1GSPS? and have a larger margin?
Any suggestions is welcome.

Thanks,
Francesco

Maybe 500Ms/s and 1 Ms ram. Really long record lengths have some specific
usefulness.

?-)
 
R

rickman

Jan 1, 1970
0
Maybe 500Ms/s and 1 Ms ram. Really long record lengths have some specific
usefulness.

Can you even buy 64 kword RAMs these days? A 32 MB SDRAM chip will do
all that is needed I believe. Either run it at 100 MHz with twice the
width of the storage needed or I expect it won't be hard to find SDRAM
that can be clocked at 200 MHz. This wouldn't add much to the cost of
the device, but would greatly improve functionality.
 
J

josephkk

Jan 1, 1970
0
Can you even buy 64 kword RAMs these days? A 32 MB SDRAM chip will do
all that is needed I believe. Either run it at 100 MHz with twice the
width of the storage needed or I expect it won't be hard to find SDRAM
that can be clocked at 200 MHz. This wouldn't add much to the cost of
the device, but would greatly improve functionality.

The 64k is a ram block inside the FPGA. Completely different situation.

?-)
 
R

rickman

Jan 1, 1970
0
The 64k is a ram block inside the FPGA. Completely different situation.

Of course... I'm used to using the poor stepchild end of the FPGA
families with only a few kB of RAM. Still, I think a RAM chip should be
on the board. It seems silly to hobble what seems to be a good design.
I know the extra storage would help the work I do.

I think I've offered my help before, but I'll make the same offer. I
have some experience with memory interfaces.
 
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