Products > Test Equipment

Keysight 3000T scope 1 GHz(or more) hardware upgrade mod

<< < (6/27) > >>

electrolust:

--- Quote from: TheSteve on June 30, 2017, 04:03:13 am ---#17 - The 50 ohm path is much improved with the updated front end and use of the Teledyne 20 dB attenuator relays

--- End quote ---

Would this part of the mod be worth doing just on its own, for a 200MHz scope, without doing the rest of the mod?  Or at 200MHz is it not gaining you so much.

Amazing:

Great job!  that really took guts.


--- Quote from: Keysight_DanielBogdanoff on June 30, 2017, 03:45:46 pm ---scope. And, as is made clear by the mod, the whole backend of the scope is capable to 1 GHz (or higher  >:D)

--- End quote ---

The first version of the 3000T manual mentions a 1.5GHz model that was never sold... 

TheSteve:

--- Quote from: Dubbie on June 30, 2017, 11:22:36 am ---I really am keen to try this but I am not sure I have the courage. Can you do it to a single channel? Or is is all or none?

--- End quote ---

This is an all or nothing mod and if you aren't sure please don't risk your scope.


--- Quote from: Keysight_DanielBogdanoff on June 30, 2017, 03:45:46 pm ---SNIP
And, as is made clear by the mod, the whole backend of the scope is capable to 1 GHz (or higher  >:D)
SNIP

--- End quote ---

Is that a challenge?
I know the front end ASIC is capable of at least 1.5 GHz as it is used in the 4000x series. My dream was a 1.5 GHz upgrade but without seeing a 4000 series 1.5 GHz front end it just isn't going to happen. It was hard enough to determine the required values for 1 GHz.
There is the jumper option on the board for 1.5 GHz but as far as I am aware it will be rejected as it isn't a 4000 series board. I have no desire to get into firmware hacking.
I don't need to sleep, I'll be pondering it.



--- Quote from: electrolust on June 30, 2017, 06:06:51 pm ---Would this part of the mod be worth doing just on its own, for a 200MHz scope, without doing the rest of the mod?  Or at 200MHz is it not gaining you so much.

--- End quote ---

There is nothing to be gained by modifying the 200 MHz front end for a better 50 ohm match. It also wouldn't work properly as the relay/attenuator controls change when you go from 100-500 to 1 GHz hardware.


--- Quote from: electrolust on June 30, 2017, 05:58:15 pm ---Can you characterize the response curve?  My memory might be bad, but as I recall from the literature, the sub-1GHz models have gaussian response and the 1GHz (as shipped from Keysight) has maximally flat response.  Apologies if the posted traces show that fact, I'm a bit excited and haven't read through in detail!

--- End quote ---

I do believe the 1 GHz model has the flat response. If you look at the anti alias/low pass filter on the output of the front end ASIC you'll see the 1 GHz model has an added series resistor/capacitor. In simulation this prevents attenuation above 500 MHz and changes the curve around 1 GHz.
I will plot the curve when I get a chance.

KE5FX:

WastelandTek:
wowwwww...

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod