HLA Feature Request - Virtual Analog Channel

I’d like to see possibility to add virtual analog channel, where HLA (or regular analyzer) can inject signal values decoded from digital frames (like I2S, PCM, PWM) as samples to visualize it as waveform.

Yes, a variety of us have already asked for such things. So, the good news is that they know we want it. The bad news is that it isn’t likely to happen instantly or soon. You might go to the ideas site and vote for the ideas you’d most like to see: https://ideas.saleae.com/b/feature-requests/

I think you’ll find that your idea is already there so you can vote for it to amplify its visibility.

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Hey, Rani from the Saleae here. First of all, welcome to our forum :slight_smile:
As @Collin said, we’d love to add that feature but we don’t have a timeline yet. However, I’d love to learn more about how you’d like to use a feature like that. Would you like to see the graph side by side with the digital data or just to be able to easily draw it?
For example, we had an idea of attaching Python Notebooks and allow users to analyze (and draw) the data using them.

What do you think?

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I’d like analog output best as a new trace so it is easy to align in time with other data. I wouldn’t care so much if it lagged during sampling, or even if it wasn’t shown at all until after sampling stopped. I can think of use cases however where the calculated data was the most important thing during sampling to determine when an interesting event has occurred.

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yes. I was also thinking to have separate window to show this, but it will be better to have it as analog output (virtual) where samples are generated on the start or end frame (might be configured). This allow us to correlate data with analog view, use zoom functionality, markers, analog measurement enhancements, etc.

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Here (I think) is an example: displaying the current through a resistor. Use two normal analog channels to measure the voltage on each end of the resistor, then create a “virtual” analog channel that shows (V1-V2)/R. Old-fashioned analog scopes used to have an A-B probe input mode to do that.

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@rani please find a use case at Generate a new channel based on data from other channels - #3 by rei_vilo.

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I can’t understand why this doesn’t get more traction. About 2 years after someone asks this and nothing happens.
This seems a duplicate of ### Analog transformation functions and math channels which gets a lot of likes but no attention from the Saleae devteam :frowning_face:

Scaling analog signals and performing basic math operations between them would really make a lot of difference for any pro-user and make the analog sampling finally really useable (despite the lack of HW scaling - if you want that - buy a scope)

There are however no scopes that handle enough signals to real time monitor traction-inverter related -signals (3 phase currents, 3 phase voltages, gate signals, combined with interpreted SPI comms & CAN). For this the Logic Pro 16 looked like the solution, but it really misses a couple of features to live up to the task.

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Hi Johan,

I share your pain. I’m one of those that has been beating this drum for a long time. However I understand Saleae’s issue too. I work with a team developing similar software to Logic (whole different domain, but multi-channel data capture and analysis). An addition of this sort probably requires reworking the entire sampling and analysis data processing chain almost from the ground up. My guess is their 3 person dev team just can’t afford three months to half a year of not fixing any bugs or adding any other features to get this done.

On the other hand, if this is architected in right a whole bunch of other stuff becomes fairly easy. I can see picking this task up could be both compelling and a really hard call at the same time. Enough people asking will eventually tip the balance!

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Thanks Peter. I can understand (and respect) the resource limitations of the team, but I doubt that what we’re asking is structurally invasive - at least for the part that concerns modification of the data of a single channel (aka scaling). And for the part that doesn’t fit with the current architecture (if any), I wish they’d tell us.

Besides these limitations, I’ll always be a fan of this little tool :slight_smile:

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@johan Thanks for the honest feedback. I can sympathize with you here.

but I doubt that what we’re asking is structurally invasive - at least for the part that concerns modification of the data of a single channel (aka scaling).

You’re right about this. There really aren’t any major structural roadblocks preventing us from impementing analog scaling. The main bottleneck really just comes from having only 3 sw developers at the moment (In reality, 2.5, given the chip shortage struggle we’ve been faced with during the past few months). Unfortunately (and in addition), stability improvements and bug fixes are taking up more time and energy than we would like…

By the way, we received your email as well! I sent that over to our product manager, Neel, who should have reached out to you by now.

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