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Possible GW Instek GDS-1000B hack

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Mortymore:
Hi

I have a 2074E updated to 1.36 firmware version.
Putty doesn't work with 1.36.
Is there a chance to downgrade to a firmware version suitable to hack? Which one?
I've searched the web for previous firmware for GDS-2000E and found nothing so far.  |O
Can someone be kind to help me out here. I'd be much appreciated.

My scope is not actually a GW-Instek one, but is the same thing, just rebranded as ISO-Tech IDS-2074E.

Mortymore:
Thanks to a forum member that provided the necessary firmware to downgrade, and to all others involved in the solution, my scope just went from 70 to 200  :-+
Hope I don't get a speed ticket  :popcorn:

The firmware was afterwards upgraded again to v1.36 and now, some calibration and testing is due.

frogblender:
Can anyone confirm that a GDS-1054B works at 300MHz?

According to gwInstek's own website, this series of scope only comes in 50/70/100MHz versions.

rhb:

--- Quote from: frogblender on November 20, 2018, 11:21:00 pm ---Can anyone confirm that a GDS-1054B works at 300MHz?

According to gwInstek's own website, this series of scope only comes in 50/70/100MHz versions.

--- End quote ---

What's the sample rate?  Divide by 2 and you have the Nyquist frequency.  That is the maximum frequency possible.  So far as I know, no OEM changes anti-alias filters if you double the sample rate by changing channel count.  The manual and datasheet for the 1000B specify a maximum sample rate, but unlike other models do not specify if there are limitations such as the very common one of requiring you to use channels that use different ADCs in 2 channel mode.

My LeCroy DDA-125/LC684 claims a 1.5 GHz BW.  But sampling 4 channels it has a 1 GHz Nyquist.  So everything above 500 MHz is aliased unless you use 2 channel mode sampling a 4 GSa/S.  But in any case, while it meets the rise time = 0.35/BW it is at the price of 20% overshoot.  I assume that disk drive analysis measuring rise time was more important than an accurate waveform.

My GDS-2072E is hacked for 300 MHz, but the step response is identical to 200 MHz.  I've overlaid the waveforms. To do 300 MHz with the ADCs you would have to switch between two anti-alias filters.  One for 250 MHz Nyquist and one for 500 MHz Nyquist.  This is why GW does not offer a 300 MHz version of the 2000E.

A far more important issue is the amount of EMI the 2000E line emits.  The front panel is shielded and the AFE sections are shielded.  But that's all.  I'm planning to fabricate shielding for the SMPS and the main board.

If you are concerned with BW you need to buy one of Leo Bodnar's excellent 40 pS rise time 10 MHz square wave generators.  These come with a printout of the step response on a 10+ GHz sampling DSO.  Measure the rise time with a single channel and then with each of the other 3 channels.  If it really has 300 MHz BW you will see a different rise time at 1 GSa/S than at 500 MSa/S.  Most likely if you save reference traces for all the permutations of channels, they will all look the same and will have a rise time of 1.75 nS.


As part of my FOSS DSO FW project I am going to do a very detailed review of issues with the 2000E.

Sadly I have come to the conclusion that all the T&M OEMs lie every time their product doesn't quite meet the marketing specs.  For example,  Keysight calculates rise time for the MSOX3104T as 0.35/BW *except* if BW = 1 GHz, then they use 0.45/BW.  HP didn't do such things as far as I can tell.  I've bought a bunch of 20 year old HP gear in the last 18 months.  It's a delight to use and it really does meet expectations.  Keysight still does make really nice gear, but I've learned to be very skeptical of the product brochures and go over  the specifications with a fine tooth comb now.

Modern DSO design commonly  uses dual channel ADCS which will sample one channel at twice the frequency of two channels.  Typical pattern is if you use 1 & 3 both will sample at 1 GSa/S, but if you use 1 & 2 you will sample at 500 MSa/S.

TheReverend:
Could someone send me the 1.18 Firmware for science purposes so i can contribute too?

Thx in advance

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