Activity for Lundinâ€
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Edit | Post #286121 |
Post edited: |
— | about 2 years ago |
| Edit | Post #286121 |
Post edited: |
— | about 2 years ago |
| Edit | Post #286121 | Initial revision | — | about 2 years ago |
| Article | — |
Why should I not use dynamic memory allocation in embedded systems? I keep hearing that dynamic memory allocation on the so-called "heap" segment should not be used in microcontroller-based embedded systems. Pretty much every safety standard like for example MISRA C bans the use of it. And I don't only hear this in the context of safety-related applications, but it s... (more) |
— | about 2 years ago |
| Comment | Post #286049 |
Since this is an electrical engineering site, questions regarding the design of a power supply are on-topic, questions regarding where to find/buy one are not. (more) |
— | about 2 years ago |
| Comment | Post #286035 |
PCB inside a metal enclosure, either aluminium or stainless steel. Enclosure grounded to chassis, antenna connector like BNC or TNC also grounded. The enclosure partially serves as ground plane for a 1/2 wave antenna. (more) |
— | about 2 years ago |
| Comment | Post #286035 |
This particular product is for an industrial/automotive application so telling someone to wear ESD protection is simply not going to work. The product isn't allowed to break from ESD or it will piss off the customers, regardless what's written down in terms of warrenty. And regardless, suppose there ... (more) |
— | about 2 years ago |
| Comment | Post #285889 |
@#53110 Or, since this has been discussed multiple times and always without concensus, there's no reason to believe that it will get consensus this time either. (more) |
— | about 2 years ago |
| Comment | Post #285919 |
https://www.onsemi.com/pub/Collateral/AND9093-D.PDF, explains this better than I could. Basically N-channel have two advantages: it has lower Rds(on) and it often has a gate-source voltage that allows it to be driven with positive logic voltages directly from a MCU pin. (more) |
— | about 2 years ago |
| Comment | Post #285913 |
@#36396 Again, we do know from SE because all _close votes_ are public there and it's a drama factory. (more) |
— | about 2 years ago |
| Comment | Post #285913 |
@#36396 Or far more likely because I was the first person who cast a _public_ close vote to a bad question. (more) |
— | about 2 years ago |
| Edit | Post #285913 |
Post edited: |
— | about 2 years ago |
| Edit | Post #285913 | Initial revision | — | about 2 years ago |
| Answer | — |
A: Let's make all downvotes public > People will be afraid to say what they really mean. > If you don't have enough conviction in your judgement that something is wrong, then it's not worth listening to in the first place. If this discourages some borderline downvotes, OK. Downvotes aren't for when you think it might be wrong. They a... (more) |
— | about 2 years ago |
| Comment | Post #285889 |
This was discussed several times on the Codidact meta, example: https://meta.codidact.com/posts/278438. The whole network needs to have the same rules, so I think this discussion should be kept there. To have individual sites come up with individual voting rules will lead to anarchy. (more) |
— | about 2 years ago |
| Comment | Post #285878 |
All of this sounds like good ideas, I vote yes on all of your proposals. Based on the current site activity I think votes could easily be capped at 5 per day, perhaps even lower. We roughly get at most one new question per day currently. (more) |
— | about 2 years ago |
| Comment | Post #285858 |
So it seems that this would be like Papers but lower the bar of what's expected? Maybe "Articles" would be a good name? Since that implies something that might get printed in a journal but not necessarily a full scientific study, which is what I think of when I hear "Papers". (more) |
— | about 2 years ago |
| Comment | Post #285855 |
This kind of irregular voting in a short period of time would have set off an automatic protection mechanism on SE. I believe 3 down votes against the same user in a short amount of time would lead to moderators getting notified and a vote rollback kicking in, something like that - I don't know the d... (more) |
— | about 2 years ago |
| Comment | Post #285817 |
Thanks for the feedback. In this case the antenna connector is the standard horrible little U.FL, which is connected with coaxial to a bigger one grounded to chassis. The main ESD risk is when someone is connecting or removing the coax. It's quite easy to touch the center pin with ones fingers on a U... (more) |
— | about 2 years ago |
| Comment | Post #285721 |
@#53110 I have a specific problem which I thought was related to ESD. Turns out it wasn't... This question here is mostly conceptual - how would I go about placing a TVS in a RF path? (more) |
— | about 2 years ago |
| Comment | Post #285721 |
@#52935 Yes and these tests are usually not hard to pass, in my experience, I've done lot of such tests in the past. Basically if every metal part is grounded and every input from connectors is protected, you pass. But in this specific case with an antenna (connector), I'm not sure how to add protect... (more) |
— | about 2 years ago |
| Edit | Post #285787 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Creating a FAQ: how to read a datasheet How about this: - I create a meta thread here where everyone is welcome to post contents, feedback and proposed changes. - The question of the meta thread should contain a continuously updated draft, which everyone can leave feedback to for at least a couple of weeks. - Then I create a Paper cat... (more) |
— | over 2 years ago |
| Comment | Post #285782 |
I've done lots of self-answered Q&A here on Codidact, but the problem with that is that then I stand as the author and none would come in and edit the actual contents of the posts. (more) |
— | over 2 years ago |
| Edit | Post #285781 | Initial revision | — | over 2 years ago |
| Question | — |
Creating a FAQ: how to read a datasheet After reading various low quality questions Someplace Else today, it (once again) occurred to me that a whole lot of people, mostly hobbyists and engineering students, have no clue how to do the most basic thing of all: how to read a datasheet. Specifically, what the various parts such as absolut... (more) |
— | over 2 years ago |
| Comment | Post #285737 |
Any [human body model](https://en.wikipedia.org/wiki/Human-body_model) will do for now. (The one defined in MIL-STD-883 is for example available for free). Considering conducted susceptibility from other sources like charges to chassis might be the next step, but for now I'm just trying to narrow dow... (more) |
— | over 2 years ago |
| Comment | Post #285725 |
They also break in different ways. Some just are dead, conducting nothing. Others only work in one direction. And this latest one seemed to have shorted tx with rx with antenna. Which perhaps implies varied strengths of a ESD. Had it been some standing wave/impedance matching/reflection problem, I'd ... (more) |
— | over 2 years ago |
| Comment | Post #285725 |
Thanks for the feedback. It sounds as we will need to run this in a simulator or we'd be fumbling around in the dark :) In case of the tx path behind the switch, then this "pi-filter" is actually part of a larger Chebyshev filter which should be split across the switch like this according to the RF e... (more) |
— | over 2 years ago |
| Edit | Post #285721 | Initial revision | — | over 2 years ago |
| Question | — |
How to protect RF switches from ESD? Assume that I have some generic antenna connector, followed by a pi-filter/50ohm impedance matching components, then a DC blocking cap (as per the RF switch recommendations) and then a RF switch for split tx/rx semiduplex transceiver, as in this schematic: antenna schematic How do I best protec... (more) |
— | over 2 years ago |
| Comment | Post #285693 |
@#52987 I answered that comment. (more) |
— | over 2 years ago |
| Edit | Post #285698 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Are reference requests on-topic? We haven't really addressed what SE would call "requests for external resources" here. I think it's quite clear that we aren't taking shopping recommendations, as in "where do I buy this part". Asking where to find books is similar, so I'd that say such questions are off-topic. I think it would be... (more) |
— | over 2 years ago |
| Comment | Post #285693 |
I've added some details from the AN regarding PCB layout recommendations for this part, where all of this comes from. (more) |
— | over 2 years ago |
| Edit | Post #285687 |
Post edited: |
— | over 2 years ago |
| Comment | Post #285687 |
@#52987 Well I suppose, though then the question turns much too broad and complex - I don't expect anyone to go read a thick datasheet plus a bunch of AN on my behalf. I've updated the question with the expected output power where this filtering would be needed. I understand this as at high output po... (more) |
— | over 2 years ago |
| Edit | Post #285687 |
Post edited: |
— | over 2 years ago |
| Edit | Post #285687 | Initial revision | — | over 2 years ago |
| Question | — |
How to calculate the RC filter of a TCXO for a RFIC reference? I have a 30MHz TCXO circuit (TCXO datasheet) like this serving as local oscillator to a RFIC: TCXO filter The RFIC manufacturer recommends to "add filtering caps" for high RF output cases. That is >20dBm, after which I suppose they are concerned that the fundamental signal radiates back int... (more) |
— | over 2 years ago |
| Edit | Post #285648 | Initial revision | — | over 2 years ago |
| Question | — |
Standardized schematic/layout file formats for PCB CAD tools? As we know there exists numerous different kinds of PCB CAD software. The big ones seem to be Eagle, KiCAD, Altium, OrCAD, Solidworks, DesignSpark and probably a few more. When it comes to mechanical PCB file formats, there is Gerber which seems to be the universal standard. But also .dxf for mech... (more) |
— | over 2 years ago |
| Comment | Post #285543 |
@#52987 Yeah it makes sense, though why not also compensate for inaccuracy in the local oscillator and the mixer? I just checked what the datasheet of the previous RFIC I worked with and it actually says it's located on the LNA too - the RSSI is fed as input to the AGC. So maybe AGC on the IF amplifi... (more) |
— | over 2 years ago |
| Edit | Post #285543 | Initial revision | — | over 2 years ago |
| Question | — |
Location of AGC in a superheterodyne RX chain RF novice here. If using a superheterodyne receiver for the purpose of FM/FSK modulated signals, I'm wondering if the location of an optional automatic gain control (AGC) circuit is always placed on the IF amplifier in such receivers, or if there are other options? I've been reading Superhet Radio... (more) |
— | over 2 years ago |
| Edit | Post #285375 |
Post edited: |
— | over 2 years ago |
| Suggested Edit | Post #285375 |
Suggested edit: (more) |
helpful | over 2 years ago |
| Comment | Post #285346 |
That is, we did pretty much as in your upper left example picture. (more) |
— | over 2 years ago |
| Comment | Post #285346 |
Reason I ask is I've been in several projects where we placed the via more or less directly adjacent to a pad. Tight designs with 144QFP and similar. I don't know if it is actually good practice though, or if some tricks were used with solder masking or stencils. Though I don't recall the PCB vendor ... (more) |
— | over 2 years ago |
| Comment | Post #285346 |
On the actual pad or very close to it? Could you post an example picture of the proposed via layout? (more) |
— | over 2 years ago |