audiofish
Joined 11 years ago
Karma
23
Submissions
14
Member since
Aug 20
Recent submissions
Comment · 1 year ago
Same experience here, plus serial port drivers that don't work, bootloader bugs causing bricked machines in the field. This on a platform nearly a decade old! The hardware is great but the software quality is abysmal, when compared to other industrial SoC manufacturers.
Comment · 1 year ago
Really cool tool, but perhaps not for the original use-case. I often find myself trying to figure out what call tree a large Bash script creates, and this looks like it visualises it well.
This would have been really useful 6 months ago, when I was trying to figure out what on earth some Jetson tools actually did to build and flash an OS image.
Comment · 1 year ago
There are multiple NOx sources during combustion.
Fuel NOx is only one of them, which you quite rightly point out is not dominant in methane combustion due to the rarity of nitrogen in the fuel.
The dominant source in methane combustion is thermal NOx, which forms due to the extreme temperature of the combustion, causing atmospheric nitrogen to decompose and react with atmospheric oxygen.
Source: https://www.epa.gov/sites/default/files/2020-09/documents/1....
Comment · 1 year ago
Picochip?
Comment · 1 year ago
DSP engineer here:- the typical way to do this for better performance would be to do the FM modulation of each channel at a lower rate, say 100kHz, then use an FFT-based channeliser to mix each sub-band to the right carrier frequency and upsample in one step. That helps to break the n^2 problem mentioned in the article.
Comment · 2 years ago
Low cost and low power DRM radio receiver is now available for general sale.
It can receive DRM/AM/FM, with an integrated class-D amplifier.
Dev kits and modules available from Mouser: https://www.mouser.co.uk/ProductDetail/CML-Micro/DRM1000?qs=...
Comment · 2 years ago
This looks very similar to the Picochip designs used in a lot of small cellular base stations for SDR. I hope it is similar, because those were fantastic chips to program for. That influence could have come via Intel's acquisition of Picochip.
Comment · 3 years ago
You're probably right. I was put off by early DAB deployments, and haven't tried with DAB+. I would be interested to try again with the new standard.
Comment · 3 years ago
That is true, although I know of one company close to production of a <10$ module for OEMs to integrate.
Comment · 3 years ago
Agreed, but the alternative here is AM which has never been good quality. DAB was a big step down from FM quality because the choice of codec / bandwidth assigned to stations was pretty bad (and bandwidth == $$!)
Comment · 3 years ago
AM radio is a pretty poor standard considering how much power and bandwidth it uses, due much to the very limited modulation technology available in the 1920s.
DRM (no not that DRM--Digital Radio Mondiale) is a modern digital standard that promises much better spectral efficiency, power efficiency and range. See https://www.drm.org/. It is similar in concept to DAB, using an OFDM carrier, but with more robust error correction and equalisation, and lower bit rate codec to handle larger broadcast areas.
There is a hope that this could upgrade existing AM broadcast infrastructure, allowing rapid coverage of large areas without the expense of building out new towers.
The MW/HF bands are great for coverage because of the longer wavelength, relative to the VHF bands used for FM and DAB.
Comment · 9 years ago
I've done some work with Octasic's Opus DSP system [http://www.octasic.com/technology/opus-dsp-architecture]
The cores themselves are asynchronous, with all of the benefits of lower power. The memories sitting outside of the cores are clocked, however.
I remember being a little bit disturbed by the temperature dependence of the chip on wall-clock execution time but it didn't affect our applications.
It was interesting to find this stuff as a product-ready platform.
Comment · 11 years ago
This is what surprised me too!
That's just asking for problems.