Obscure Electronics Topics

The most obscure facet of electronics I've learned recently is the PWM output of the NS9360, see PDF page 145 (document page 121) :

If you concatenate the timers, you can control the pulse with and the period with both timers, but this allows 1:1, 1:2, 1:3... duty cycles, only. I wonder for what this obscure PWM output can be used for.

There is an "alternative" described in the datasheet: Just stop all interrupts, use the same frequency for both timers and start the second timer after some manual programmed delay loop. Ok, WindowsCE might crash and it might be not so fast, if you do it too often, but at least the PWM works, with a whopping precision of 1% !

Literally, sphincter tension?

Strange things have been made... Behavioral scientists need to measure sexual arousal somehow, for instance!

Tim

-- Deep Fryer: A very philosophical monk. Website @

This is already being done with CAT scans...

Oh I get it, your sexual arousal manifests as sphincter tension, that is not a good sign...

You'd prefer just the opposite, I suppose.

Best regards, Spehro Pefhany

Couldn't imagine it...don't want to either.

If you can get a copy of "Methods of Experimental Physics", volume 12, there's an astonishingly good discussion of how to make accurate measurements with PMTs.

Cheers,

Phil Hobbs

Jim's Alzheimer's seems to have gotten worse - why else would he confuse a mobile stage with a house? Maybe he's reverting to a time when he was trailer trash, and his homes all had wheels.

-- Bill Sloman, Nijmegen

D from BC snipped-for-privacy@comic.com posted to sci.electronics.design:

I don't suppose that you have tried looking for three or four winding SMD transformers?

Vladimir Vassilevsky antispam snipped-for-privacy@hotmail.com posted to sci.electronics.design:

I am pretty curious about the physical understanding / application of the 3D FFT.

Not yet... But would that SMD transformer be 1206 size? Tapped 100uH. Small signal current.

D from BC

The understanding is pretty simple: imagine a cube where the FFT is computed along X, Y, Z. This works very good for the applications like video compression, where the third dimension is time. The 3d FFT approach is capable of better compression then the traditional schemes like MPEG, and the computing workload is significantly lower. However in MPEG the decompressor requires somewhat 100 times less of processing, then the compressor, whereas in the 3d FFT approach the decompressor demands are comparable to that of the compressor. So the decoders for MPEG are cheap and simple, and all of the complexity is on the encoder side. This is better for the typical consumer video applications.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

D from BC snipped-for-privacy@comic.com posted to sci.electronics.design:

Nobody else will know until someone looks and posts back here.

Spehro Pefhany found something that may be similar.

Well, there are SMT common mode chokes intended for removing common mode noise on differential lines. If you connected the dot side of one coil to the anti-dot side of the other coil, you would have a center tapped autotransformer.

Depending on what you are trying to do, those might serve. They are quite small.

Example: Murata DLW21HN670SQ2L

Digikey has them.

Well whatdayahknow....

But I'm not sure how to go from common mode impedance to inductance... The common mode impedance is 67 ohm at 100Mhz. I'll guess 67/2 = 2*Pi*100Mhz*L

If so...that's ~53nH...Perhaps that's why it's so small.

I'll look for similar CM xformers at 100uH.

Thanks.. D from BC

Yeah, it is dicey to assume that the impedance is purely inductive.

Murata also has parts in a bigger package up to 2200 Ohms at 100 MHz. I still don't think that will get you where you need to be.

I think TDK also makes them.

In the end, I suspect Win's advice is the best. ;-)

--Mac