S&H section of Noise Tools 1U behaving weirdly

I just put my 1U noise tools module back in a Palette case and noticed that the S&H section does not seem to behave properly.

The trigger generator works fine, the noise and the slew too. But the S&H very briefly samples the incoming signal when it gets a trigger but does not hold it. In T&H mode, the same happens : when tracking it does follow the incoming signal but when holding it only does it for a very short time.

The LED is basically red most of the time.

The modules has Rev001.03 marked on the PCB, it used to work fine previously (in a 7U case). I looked at the PCB but did not see anything that looked wrong.

What could be the cause of this issue ?


If I’m not mistaken, what you are referring to I addressed recently here:

Intellijel confirmed via email that this is an ongoing bug with this module. It’s only supposed to sample at the rise of every pulse but it samples at the rise and fall. If you bypass the internal clock (send something to the TRIG input), or route the internal clock elsewhere and send it back to the TRIG input, it will operate as intended and only sample once per clock cycle.

No, I think @oscillateur is describing something else that sounds like a hardware fail. Please reach out to support@intellijel.com

Noise Tools should hold the S&H values steady until they update. T&H will pass the incoming signal while the gate is high. If a sampled value drops in voltage there is probably something wrong with it.

The bug @r_omega described is that if you connect something to the PULSE output, the internal S&H circuit switches from only sampling on the rising edge to sampling on both the rising and falling edge, effecting doubling the S&H rate. This effect can be eliminated if you connect the PULSE output to a buffered mult.

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Out of curiosity, will this Noise Tools bug be fixed with a future hardware rev?

It was fixed several years ago. Single resistor value change.

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I bought one January 2021 and it had the issue with S&H happening on both the rise and fall of the internal clock pulse. Is that the issue you’re talking about? At the time you guys said it’s just an ongoing bug that hasn’t been fixed so I’m confused.

That is not normal. The issue only happened if you patched with a cable from the pulse out to the trigger in. And this only happened on early batch of Noise Tools. If your unit is double sampling then you should contact support. Also make sure you are not in T mode instead of S.

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