Search found 15 matches

by geshsoft
Fri Mar 01, 2013 7:00 am
Forum: DSO
Topic: Alternative dso firmware [Application Software Design Entry]
Replies: 77
Views: 118247

Re: Alternative dso firmware [Application Software Design En

I reinstalled the latest community edition files as well as FPGA firmware and now I was able to install gabonator's app. I've got to say I most definately looked like this :D after I run through the GUI. It is very well though out and very responsive. Even the candy look is there! :mrgreen: That is ...
by geshsoft
Fri Mar 01, 2013 3:23 am
Forum: DSO
Topic: Alternative dso firmware [Application Software Design Entry]
Replies: 77
Views: 118247

Re: Alternative dso firmware [Application Software Design En

Hi, I'd really like to try the app but each time I flash it the DSO comes back with .err file. I attempted older hex files that were slightly smaller (433k or so) with the same results. I have no issues loading the latest community edition though. Am I missing something? :?
by geshsoft
Thu Nov 01, 2012 4:19 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

timbeurskens, LMH6626 is not even remotely close of a substitute for OPA2354 in this case. The specs are all wrong. For instance, LMH6626 is not rail-to-rail rated op-amp which means that your dynamic range will suffer greatly. The input bias current of LMH6626 is 7 orders of magnitude greater than ...
by geshsoft
Sat Oct 15, 2011 4:26 pm
Forum: DSO
Topic: Upgrade ADC
Replies: 4
Views: 3687

Re: Upgrade ADC

Shodan_x, oversampling would not do much since the analog BW is pretty much limited to about 10MHz (and it is not flat either). If the ADCs are pin by pin compatible then the replacement will require good soldering skills and changing the speed of the clock signal, which I assume is generated by the...
by geshsoft
Tue Aug 23, 2011 9:55 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

Noname, I agree that the device specs were overstated - both the analog BW and sampling rate. However, I disagree that the mod posted by bielec is misleading. bielec stated: "I now get about 10MHz sinewave bandwidth on all ranges and good pulse response with minimal overshoot and rounding. Trigger a...
by geshsoft
Mon Aug 22, 2011 3:05 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

Noname, a square wave is not a good merit to justify that the mod does nothing. After the modification the analog BW rolloff is extended to around 10MHz... In other words, the effective sampling rate of the quad as well as the analog BW of the front end is not good enough to accurately display a squ...
by geshsoft
Fri Jul 29, 2011 12:14 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

flyingdave my bad about the resistors - I changed 2 and reverted back to the original as they made no difference, so it is just capacitors really.
by geshsoft
Wed Jul 27, 2011 8:11 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

Well, mine stock had 3dB anywhere from 400kHz to 1Mhz depending on the vertical scale selection. After patching up the front end the 3dB is now shy of 11Mhz for vertical scale settings. I implemented similar to bielec's solution (almost the same). The parts I used are low drift resistors (25ppm 0603...
by geshsoft
Thu May 19, 2011 12:02 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

Yes I agree with the fact that the simulation is just a rough approximate of the real world performance which is not accommodating for parasitics, and I did state so. The gerber files would be something I'd definitely want to see. I opened up the scope yesterday and the R and C are definitely smalle...
by geshsoft
Wed May 18, 2011 5:29 am
Forum: DSO
Topic: DSO Quad bandwidth
Replies: 117
Views: 127729

Re: DSO Quad bandwidth

In order to achieve higher BW multiple smaller gain stages are needed. The example below shifts the cutoff to about 27MHz. I think I will try the first solution as it is fairly straight forward given the parts are not something smaller than 0805… DSOQ_FE_Schematic_Dual_Stage_Optimized.jpg DSOQ_FE_F_...