lpmay

I would never have guessed this configuration was so rare. D-sub connectors seem to have more active use in aerospace and defense that you might expect (Until I started working professionally, I always associated them with "old" computers, not high end stuff).

yes sorry, pitch is smaller density is higher

The important distinction is between on-silicon interconnects and off-silicon. On silicon, the interconnect density is much higher so it's feasible to get high bandwidth by having lots of "channels" (wide busses). This becomes less desirable off chip (on the PCB) for many reasons. Some of them are: 1) The interconnect density is much lower, and having such a large bus becomes physically large 2) The bus is larger and less precise, which makes maintaining skew between channels more and more challenging 3) The parasitic capacitance/inductance (i.e. energy storage) of the bus becomes larger as it gets physically larger, meaning each channel needs a relatively large driver circuit (which costs expensive silicon area) and dissipates more power to drive correctly, and even more power if the speed is increased.

Increasing the symbol complexity of each channel does more than just move the bottleneck around, because it allows fewer chip to chip interconnects to carry more data.

I don't work in this regime, but as a layman I'm not convinced using full QAM for on-board chip to chip interconnects makes sense. One major advantage you natively have over the RF case is you can be easily coherent (shared clock). Throwing this away to do carrier recovery introduces a lot of complexity and potentially reduces the available bandwidth. Assuming you transmit without a carrier, can you have "baseband" QAM without a separate I and a Q signal? If you transmit an I and Q signal separately, does that not just become the same thing as two PAM-32 signals?

The "PIC32" family from microchip is also MIPS based

No problem! You are not the first person I've heard express the impression that the MSP430 is slipping into irrelevance, and while I agree the places it shines may be getting squeezed by low power ARM parts I think they can be pretty compelling for applications where they are a good fit. They are simple, yet modern enough to support full featured c compilers, have a history of focusing on low power and the FRAM is a pretty solid differentiator if your use case can take advantage of it. Jay's article here can't really show any of that off because the one dollar price point is below the sweet spot where most of the nice features kick in

I think the platform is very much still alive and kicking. It is still the only uP platform I am aware of which is available with embedded FRAM which is low power, non volatile, extremely more write durable than flash and rad hard. Again, maybe not top selling features for a hobbyist project but absolutely compelling for certain industrial use cases.

It's up to hobbyists what's worth it to them, but the power consumption of the ESP 8266/32 is not _really_ comparable to the '430. "Deep sleep" mode on the ESP seems to be about 20uA, an MSP430FR5969 can go to a 20nA LPM 4.5 mode (factor of 1000 lower). Harder to compare in a HN comment, but active mode power consumption is also in the MSP's favor for many applications particularly when using the built in hardware accelerators like LEA.

Of course the MSP430 doesn't have a WiFi modem or a giant hobbyist community like the ESP, so I'm really not trying to make an argument for which is "better" just trying to add some contrast to the low power features you asked about.

Don't know if their copy editors read these, but "Gallium Nitrate" is surely a typo for "Gallium Nitride" (GaN). GaN is a wide bandgap semiconductor, Gallium Nitrate is apparently some sort of drug.

It's because the speed of sound (in any material) is much slower than the speed of light (even in high dk materials). To make a selective and low loss filter you want to use resonators which have dimensions which are a large fraction of a wavelength (i.e. a quarter wave). When the wave speed is slower, a wavelength is compressed into less space ( cycles per second / meters per second ) which is what enables the miniaturization.

I believe the acoustic loss in many of these materials is also lower than the dielectric loss in most materials, which also improves filter q and achievable selectivity.

Just a hint - extra attributes in the `mkShell` appear as environment variables in the built shell. So instead of a `shellHook` for this you can just have an attribute `ERL_LIBS="";`

I'm not completely sure but I think this approach is preferred because shellHook only runs in `nix-shell` but if you ever wanted to `nix-build` a release it might not run.

Also see meson's[0] built in package management called wrap-db[1]

[0] https://mesonbuild.com/ [1] https://wrapdb.mesonbuild.com/

Down to DC? That should be a surprise, because it's certainly not true! Faraday's law of induction only applies to varying fields, which means AC or physical movement. Remember, it's perfectly normal and common to have a square wave with a DC component of zero!

What is "OBD-C"? Did the appropriate the USB-C connector for an OBD connection for some reason?

No, the power consumed is equal. The capacitance doesn't stop charging at time tao as you imply, it continues to charge until it reaches the final driving voltage, which is why integrating to infinity is a (very) much closer approximation

No, the power consumed is equal. The capacitance doesn't stop charging at time tao as you imply, it continues to charge until it reaches the final driving voltage, which is why integrating to infinity is a (very) much closer approximation

Yes, but I don't think your refuted my point. 16 bits (96dB SNR) is pretty good for an 18MHz signal processing system. Comparing it to a 18MHz 8bit AVR with a 10bit, 15ksps ADC is probably missing what makes this potentially cool.

Don't get me wrong, I think this is a pretty niche thing that doesn't have a lot of applications. DSP is great, and it's not going to get overthrown anytime soon. But if you were looking for things that make signal processing in the analog domain exciting to think about, I stand by high equivalent bit depth for the processing bandwidth and power consumed as a valid advantage.

Sure, but analog processing happens continuously and at an SNR that is equivalent to a very high bit depth. If you had an analog processing chain with 18MHz of BW (which granted you'd need somewhat more GBP), that would be more akin to a digital system that can produce output samples at 40Msps+. If each output sample needed even just a few dozen processing clocks to compute, you're already looking at a 500MHz+ clock. Although you could build that digital solution, it wouldn't surprise me if the analog solution was significantly lower power.

The Waytools text blade sounds somewhat similar to what you're describing:

https://waytools.com/

I love this article, but I just can't help but pick at this nit I have with the "charging the capacitors" part. I'm not intimately familiar with Ethernet specifically, but I am an electrical engineer. Since the voltage on a capacitor is directly related to the charge it has stored ( scaled by a factor called it's capacitance :-) ), holding the capacitors at any fixed voltage for any length of time does not change how "charged up" it is at all. I would believe that there is a "line balancing" goal to the transmissions, but I'd be willing to bet it is to avoid driving the isolation transformers into saturation, and has nothing to do with low pass filter capacitors...

Nice.

Do you have any guides you wrote or used that you can recommend? I'm looking at getting SmartOS set up at home as well, but I know I've got a lot to learn.

Maybe even hotter than inside, since the epoxy reaction is exothermic as it cures.

Another cool thing, that was counter intuitive to me is that more than just rejecting multipath, spread spectrum can actually make use of multipath to improve the link (although I doubt it is done much in practice).

Conceptually, what you do is correlate on the incoming signal like normal, this first lock is the dominant path. You take the component that correlated and subtract it from the incoming signal and correlate again on what remains. This lock is the second multipath. You can do this to recover as many multipaths as you want or have dynamic range for. Finally, the relative offsets in the correlations tell you how to re-align all the multipaths in time. Once they are aligned you can sum them together and get more SNR than if there had been no multipath at all.

Also, the input stage is where noise figure is critical. Larger transistors are lower noise figure.

Yea, it's quite possible that something changes at these (scary) high charge rates. Maybe charge efficiency takes a nosedive, or there are some other effects that are non-linear with charge rate. Thanks for the link.

Oh, no doubt heat is also not good for batteries (neither is the cold). I didn't mean to imply it wasn't.

However I'm still not sure heat is the first order effect limiting charge rates. If you consider that the charge efficiency of the cell is something around 99%, the total losses at a 1C rate relative to the thermal mass of the cell are pretty negligible ( nominally, around 3.6mW per A of charge current ). I'd wager that when your cellphone heats up under charge, that's primarily due to losses in the ~90+% efficient charger circuitry. Heat is heat, and that is still not good for the battery of course. I believe the cooling system in the Tesla is primarily for when the cells are being discharged, but it would be really interesting to hear the full story on that from a Tesla engineer.

I found the below link which also seems to imply the lithium plating as well as other chemical effects are the first order issues. http://batteryuniversity.com/learn/article/bu_808b_what_caus...

I'm not an electrochemist, but I have been told one of the major wear mechanisms is lithium plating, which is a function of anode voltage and charge current (and probably 100 other things). As I understand, the standard CI/CV charge cycle is very conservative to avoid this complexity. I believe more sophisticated parts like the TI Max charge series get around this by running estimators of the cells anode voltage and can scale charge current appropriately.

Sorry no good references to offer off hand, this is all just stuff I've been told by engineers and chemists. Take with a grain of salt.

Mixers are physical systems. The precise words for the distinction you are trying to make is between linear and non linear systems.

I don't see it mentioned here, but the dask library looks like a promising solution,. It has ways to handle to these kinds of large datasets, and efficiently schedule computations that don't fit a numpy model. Worth a look.

For the antenna case (and I believe for the optics case too, but I'm not an optics guy) the beam disperses as 1/r^2 in both cases.

In transmit , the reflector provides focusing, which puts more power in less of the volume. In receive, the increased aperture allows the antenna to capture a greater area of the incoming wave giving more receive power. The effects are equal and usually just thought of as"gain" which is reciprocal for transmit and receive.

Interesting. I've used an EM and antenna simulation tool called FEKO that is also originally from South Africa. Is there a university there with a strong electromagnetics focus?