Looking for references about PC oscilloscope

[wakaka]

Hi guys, I've browse thru the forum, but still cant find any clear source regarding a PC oscilloscope. But I've found this thru google :
**broken link removed**

Although its not a PC osc, but it looks nice, plz comment guys.
And plz recommend a better scope, either PC osc or a portable osc which can be fully built from scratch.

THankx

 

[CMOS]

Re: Pc oscilloscope

There are no good complete sources for building your own PC oscilloscopes. Even I have been searching for something complete for years now but still haven't found one that I am looking for. All the projects that I know are either have too low bandwidth or the ones which have good usable bandwidth are left incomplete.
My advice....don't waste your time in searching....just buy one! Or if you have time...you can wait for someone who makes something useful.

The developer of **broken link removed** said in a PM that he has been working on his project since a month or so after a long gap. SO lets see what he comes up with. BTW his design is quite impressive.

 

[wakaka]

Pc oscilloscope

the link fails......again?

 

[Iridium77]

Pc oscilloscope

I've been looking for something similar and I found the Bitscope. It is a commercially made USB oscilloscope but they put all the design information and software on their website so you can build your own from scratch.

It's based on a PIC but I'm an Atmel fan so I haven't tried making one... yet.

https://www.bitscope.com/design/

 

[CMOS]

Re: Pc oscilloscope

It is a commercially made USB oscilloscope but they put all the design information and software on their website so you can build your own from scratch.

No...Software is not made open to public. Also PIC16F628 and CPLD firmwares are not available.

Added after 13 minutes:

the link fails......again?

Yes the link is not working since few days. I have his website saved on my PC. Here it is if you are interested.

 

[wakaka]

Pc oscilloscope

if a scope's bandwidth is 100Mhz, meaning it can measure a signal with freq up to 100Mhz rite?

But wat is the sampling rate? the higher the better?
for this h**p://www.semifluid.com/ , it claims that the actual sampling rate is aroung 60kHz, wat does that mean??

Wat is the ralation between sampling rate and bandwidth?

 

[jonw0224]

Pc oscilloscope

wakaka,

Nyquist says you must sample at atleast twice the greatest frequency within a waveform to "see" that frequency. So, theoretically 60 kHz sampling means a 30 kHz bandwidth. However, this is good for sine waves and assumes perfect signal reconstruction.

Most people say that you need at least 10 samples per period to see anything interesting. I'm not sure where 10 samples comes from, but that implies a 6 kHz bandwidth. Basically, a 60 kHz oscilloscope is not much better than a sound card. There are free softwares which convert a sound card into an oscilloscope.

I've been working on a PIC16F877 implementation that samples at 1 MHz. Software development is my current problem. I have the beginnings of the project on my website but haven't updated it in a while. If you're willing to struggle with a DOS interface which will run on Windows 98 you can use whats there. I'm actually quite close on a Windows based GUI for the oscilloscope. I plan for the software and hardware design to be completely open source when I complete it.

I've seen similar projects but nothing completely documented or open source as CMOS explains. If you're not willing to wait for me (or someone else) to come up with something worth releasing (been working off and on on this project for a while), I'd suggest buying a used analog scope.

-jonathan

 

[wakaka]

Pc oscilloscope

yes i'm interested. CAn u post ur website here? so that whoever interested can view it.....

Added after 5 minutes:

got ur website thru google....

https://jonw0224.tripod.com/ppmscope.html

 

[jonw0224]

Pc oscilloscope

...or you could have checked my profile or used the www link below my post.

Sorry it wasn't clear.

-jonathan

 

[echo47]

Re: Pc oscilloscope

if a scope's bandwidth is 100Mhz, meaning it can measure a signal with freq up to 100Mhz rite?

The scope's frequency response is typically down -3dB at its bandwidth limit, so a 100MHz 1.0 volt sinewave would appear to be about 0.7 volts.

 

[togarha]

Re: Pc oscilloscope

Hi,

jonw0224,

-Do you think to add usb connection to your module? May be it's interesting to do.
-And the possibility to add digital interface to use as a data logger?

-If you need any help in pcb proccess or something else, do not hesitate to contact with me...

togarha@alumni.uv.es

Regards,

Tomas

PS: The send comment page inside ppm osciloscope page don't work fine, the page displays this message "Sorry, but the page or the file that you're looking for is not here." when you try to send the form with the comment...

 

[jonw0224]

Re: Pc oscilloscope

Tomas,

Hi,

jonw0224,

-Do you think to add usb connection to your module? May be it's interesting to do.

Yes, I'd like to eventually, but have focused on the parallel port and next i will focus on the serial port for now.

-And the possibility to add digital interface to use as a data logger?

Yes, I've thought of this, but it seems that a separate device would be better suited to do this. You could put this in a single device, but I think it would unnecessarily complicate the user interface and the device itself. The microcontroller in my design dedicates itself full time to getting a sample data set after a trigger. There is no processing time to do anything else. At minimum another microcontroller would be required. Instead, am focusing on different sampling methodologies etc. to extend the capabilities of the scope. A BITSCOPE sounds like a design you'd be interested in. It has both features you ask about.

-If you need any help in pcb proccess or something else, do not hesitate to contact with me...

togarha(at)alumni.uv.es

Regards,

Tomas

PS: The send comment page inside ppm osciloscope page don't work fine, the page displays this message "Sorry, but the page or the file that you're looking for is not here." when you try to send the form with the comment...

Thanks for the offer, the comment page should be working now. There was a problem which surface for mozilla but internet explorer was tolerant of. The script to send the e-mail would run, but the redirect didn't work properly. Thanks for the heads up.

-jonathan

 

[wakaka]

Re: Pc oscilloscope

Whats the Max and min voltage it can measure for ac and dc?

 

[jonw0224]

Pc oscilloscope

Depends on the position of the gain switch on the analog part of the input.

For Gain = 1
Vmax = 10V, Vmin = -10V, resolution about 100 mV

For Gain = 2
Vmax = 5V, Vmin = -5V, resolution about 50 mV

For Gain = 5
Vmax = 2V, Vmin = 2V, resolution about 20 mV

If the input is AC coupled, the signal cannot be outside of 10V and -10V and the numbers above represent differences from the DC offset which is filtered out when the input is AC coupled.

-jonathan

 

[jonw0224]

Pc oscilloscope

It's been a while since I've posted, but I've updated the oscilloscope software/firmware/schematic on my website today. It's a major step in increased functionality with lots more documentation (the result of the past few months of tinkering). Perhaps someone is interested:

https://jonw0224.tripod.com/ppmscope.html

-jonathan

 

[seadolphine2000]

Pc oscilloscope

Check this one:
http://www.geocities.com/lptscope/index.html

It's the simplest one you can find.

 

[psmll]

Re: Pc oscilloscope

I've been working on a PIC16F877 implementation that samples at 1 MHz.

Try the dsPICs some have ADCs at 1.1 MSps

 

[jonw0224]

Pc oscilloscope

Hey guys and gals,

Sorry, but in my excitement I uploaded a zip file with a minor error (related to removing the debug features from the source code). Sorry for the inconvenience to anyone who has downloaded it already.

The link is a couple of posts above, or just hit the www button at the bottom of this post.

-jonathan