120 Degree Phase Shift Osc.

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serving

You would not be serving me, but yourself - as long as you don't provide the quote on which you base your claim that I am a liar, the suspicion has to be that you made a mistake and are too dishonest to admit it.

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tasheet

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Keil make development systems for microprocessors. You claimed to have got your data sheet from the Intel web-site. There seems to be more than ten seconds of searching involved in bridging that difference.

I also note that datasheet is labelled preliminary, and dated December

1995 - which is fifteen years ago, not twenty. It seems that your claim about a twenty year-old micro was based on a misapprehension, in much the same way as your claim about me being a liar.

You really do seem to be losing your wits.

-- Bill Sloman, Nijmegen

--
Shame on you.

That's a nonsensical red herring and has nothing to do with whether
the word "rheostat" has currency here.

hree

ip-

H-bridge? Just make the 3x signal* and sum them--two resistors instead of one.

*Using JF's spare flop.

-- Cheers, James Arthur

om

three

flip-

20

Depends what you are doing - in Mark Weaver's circuit it would save you the resistors. His application would work fine with an H-bridge, though you'd need to measure the coil inductance and figure it into a low pass filter structure.

-- Bill Sloman, Nijmegen

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

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it happenedBillSloman

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wrote:

(PDT),BillSloman

wrote:

(PDT),BillSloman

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until

about it.

Wrong. I know how to design. You don't.

Wrong, liar. I have no interest in jumping your rope.

that

datasheet

More proof that you're a liar, too. I said I found it by searching the web.

I used the FC version in a product that first shipped in '90. I wasn't even working in the same location in '95. I had it a bit before '95, dummy.

More lies from Slowman as he continues to attempt to bury the world in his bullshit.

m

.com

ed three

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120 a d e t

Yes, if you already had an H-bridge that would work.

Here's John Fields' circuit with the 2-resistor thing. I threw in an integrator too to make a segmented approximation to a sinewave, then fed into John's lowpass.

I railed the integrator lightly to get 8 segments--two extra segments and flat tops for free.

Even harmonics are suppressed, 3rd harmonic is 40bB down, 5th and higher harmonics all lower.

None of it's optimized--I've got to run.

Cheers, James Arthur

------------------------ Version 4 SHEET 1 1624 1476 WIRE -224 -112 -256 -112 WIRE -112 -112 -144 -112 WIRE 224 -16 96 -16 WIRE 352 -16 224 -16 WIRE -1856 0 -2448 0 WIRE -1600 0 -1856 0 WIRE -1376 0 -1600 0 WIRE -1088 0 -1376 0 WIRE -864 0 -1088 0 WIRE -592 0 -864 0 WIRE -256 0 -256 -112 WIRE -256 0 -288 0 WIRE -208 0 -256 0 WIRE -112 0 -112 -112 WIRE -112 0 -144 0 WIRE -64 0 -112 0 WIRE 96 16 96 -16 WIRE -1856 48 -1856 0 WIRE -1600 48 -1600 0 WIRE -1376 48 -1376 0 WIRE -1088 48 -1088 0 WIRE -864 48 -864 0 WIRE 224 80 224 -16 WIRE 240 80 224 80 WIRE -1936 96 -1968 96 WIRE -1744 96 -1776 96 WIRE -1680 96 -1744 96 WIRE -1456 96 -1520 96 WIRE -1232 96 -1296 96 WIRE -1168 96 -1232 96 WIRE -944 96 -1008 96 WIRE -416 96 -784 96 WIRE -288 96 -288 0 WIRE -288 96 -336 96 WIRE -208 96 -288 96 WIRE 352 96 352 -16 WIRE 352 96 304 96 WIRE 416 96 352 96 WIRE 480 96 416 96 WIRE -64 112 -64 0 WIRE -64 112 -144 112 WIRE -16 112 -64 112 WIRE 96 112 96 80 WIRE 96 112 64 112 WIRE 128 112 96 112 WIRE 224 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SYMATTR Value PULSE(-3 3 0 1E-6 1E-6 .008333 .016666) SYMATTR InstName V1 SYMBOL cap -2096 240 R90 WINDOW 0 -33 25 VBottom 0 WINDOW 3 -33 27 VTop 0 SYMATTR InstName C1 SYMATTR Value 100nF SYMBOL res -2064 304 R90 WINDOW 0 68 58 VBottom 0 WINDOW 3 71 58 VTop 0 SYMATTR InstName R1 SYMATTR Value 100k SYMBOL Digital\\dflop -1600 48 R0 WINDOW 3 8 168 Invisible 0 SYMATTR Value trise 1e-7 tfall 1e-7 vhigh 3 vlow -3 SYMATTR InstName A2 SYMBOL Digital\\dflop -1376 48 R0 WINDOW 3 8 168 Invisible 0 SYMATTR Value trise 1e-7 tfall 1e-7 vhigh 3 vlow -3 SYMATTR InstName A3 SYMBOL Digital\\dflop -1088 48 R0 WINDOW 3 8 168 Invisible 0 SYMATTR Value trise 1e-7 tfall 1e-7 vhigh 3 vlow -3 SYMATTR InstName A4 SYMBOL Digital\\dflop -864 48 R0 WINDOW 3 8 168 Invisible 0 SYMATTR Value trise 1e-7 tfall 1e-7 vhigh 3 vlow -3 SYMATTR InstName A5 SYMBOL cap 192 432 R0 WINDOW 0 -41 34 Left 0 WINDOW 3 -88 65 Left 0 SYMATTR InstName C7 SYMATTR Value 11nF SYMBOL cap 64 320 R0 WINDOW 0 -55 -2 Left 0 WINDOW 3 -87 35 Left 0 SYMATTR InstName C8 SYMATTR Value 22nF SYMBOL res 64 400 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R7 SYMATTR Value 1meg SYMBOL res 208 400 R90 WINDOW 0 -30 53 VBottom 0 WINDOW 3 -28 56 VTop 0 SYMATTR InstName R8 SYMATTR Value 1meg SYMBOL voltage -2208 496 R180 WINDOW 3 37 109 Invisible 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 0 -41 6 Left 0 SYMATTR Value 3 SYMATTR InstName V4 SYMBOL voltage -2304 384 R0 WINDOW 3 37 109 Invisible 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 WINDOW 0 14 107 Left 0 SYMATTR Value 3 SYMATTR InstName V5 SYMBOL cap 208 128 R0 WINDOW 0 -41 34 Left 0 WINDOW 3 -88 65 Left 0 SYMATTR InstName C2 SYMATTR Value 11nF SYMBOL cap 80 16 R0 WINDOW 0 -55 -2 Left 0 WINDOW 3 -87 35 Left 0 SYMATTR InstName C3 SYMATTR Value 22nF SYMBOL res -320 80 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R2 SYMATTR Value 100k SYMBOL res 224 96 R90 WINDOW 0 -30 53 VBottom 0 WINDOW 3 -28 56 VTop 0 SYMATTR InstName R3 SYMATTR Value 1meg SYMBOL cap 192 752 R0 WINDOW 0 -41 34 Left 0 WINDOW 3 -88 65 Left 0 SYMATTR InstName C4 SYMATTR Value 11nF SYMBOL cap 64 640 R0 WINDOW 0 -55 -2 Left 0 WINDOW 3 -87 35 Left 0 SYMATTR InstName C5 SYMATTR Value 22nF SYMBOL res 64 720 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R4 SYMATTR Value 1meg SYMBOL res 208 720 R90 WINDOW 0 -30 53 VBottom 0 WINDOW 3 -28 56 VTop 0 SYMATTR InstName R5 SYMATTR Value 1meg SYMBOL Opamps\\LT1677 272 32 R0 SYMATTR InstName U1 SYMBOL res 400 112 R0 SYMATTR InstName R6 SYMATTR Value 1k SYMBOL res 384 416 R0 SYMATTR InstName R9 SYMATTR Value 1k SYMBOL res 384 736 R0 SYMATTR InstName R10 SYMATTR Value 1k SYMBOL Opamps\\LT1677 256 336 R0 SYMATTR InstName U2 SYMBOL Opamps\\LT1677 256 656 R0 SYMATTR InstName U3 SYMBOL res -320 208 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R11 SYMATTR Value 200k SYMBOL Digital\\dflop -592 128 R0 WINDOW 3 8 168 Invisible 0 SYMATTR Value trise 1e-7 tfall 1e-7 vhigh 3 vlow -3 SYMATTR InstName A6 SYMBOL res 80 96 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R12 SYMATTR Value 1meg SYMBOL Opamps\\LT1677 -176 48 R0 SYMATTR InstName U4 SYMBOL cap -144 -16 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C6 SYMATTR Value 200nF SYMBOL res -128 -128 R90 WINDOW 0 65 62 VBottom 0 WINDOW 3 70 60 VTop 0 SYMATTR InstName R13 SYMATTR Value 1meg TEXT -2432 560 Left 0 !.tran 1.3S startup uic TEXT -2432 592 Left 0 !;ac oct 128 1 100 TEXT 464 720 Left 0 ;>PHASE 1 TEXT 464 400 Left 0 ;>PHASE 2 TEXT 480 96 Left 0 ;>PHASE 3 TEXT -1168 -200 Left 0 ;Three-phase sine generator, idea by John Fields

three

flip-

You'd have done better on the 3rd harmonic - which is the hardest to filter - if you'd set R11 to 300k rather than 200k. Clipping is not your friend when it comes to the third harmonic. I had to drop R13 to

56k to see the 3rd harmonic at 80dB down, as well as throwing away most of the "integration" by reducing C6 to 33nF. The fifth harmonic ended up at 40dB down and the seventh at 50dB down. Increasing C6 above 33nF makes the 3rd harmonic content higher and doesn't make much difference to the 5th and 7th harmonics.

An extra couple of poles of output filtering would get the 5th and 7th down to the -80dB level too.

Don Lancaster's "magic sine" binary sequences could probaby do quite a lot better. They can be concocted to suppress the first 20 harmonics.

-- Bill Sloman, Nijmegen

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

it happenedBillSloman

(PST)) it happenedBillSlom=

:

wrote:

(PDT),BillSloman

wrote:

(PDT),BillSloman

(PDT),BillSloman

be

until

about it.

serving

You may know how to design - though we've not seen any evidence of it here - but this is notrelevant at this point. What you need to understand is that if you make a claim and can't - or don't - supply the obvious evidence that would support your claim, objective observers will find your claim less than credible, and will also become sceptical about every other claim that you make where supporitng evidence may be harder to come by.

One wonders what you are actually interested in. Granting your enthusiasm for calling me a liar in every alternative sentence, there does seem to be some evidence of personal animosity, and there's not much evidence of anything else.

that

datasheet

True. I can't imagine why I thought that you said that you'd found it on the Intel web-site. You aren't only one who suffers from occasional misapprehensions.

But that data sheet clearly doesn't apply to a device that you used in a product that you shipped in 1990. So you haven't found the data sheet for the part that you used. The part number that you have been touting clearly wasn't available in 1990, if the data sheet was still preliminary in December 1995

A preliminary data sheet from 1995 for a device that you claim to have used in 1990? It's not me who is peddling implausible bullshit here. You may think that the rest of the world is composed of gullible nitwits, but we aren't as gullible as that.

-- Bill Sloman, Nijmegen

I'm burning the past-midnight AND early morning oil right now, so I thank you for experimenting with it.

ISTM a pseudo-sine made of line segments into the final filter will give purer output than a stair-stepped approximation into the same 2- pole filter, because the filter isn't very tight. I don't know though--I haven't given it much thought.

I know it's possible to perfectly cancel the 3rd harmonic by choosing the ideal resistor ratio, and meant to go 3:1 due to the Fourier weightings. The 2:1 value ratio did that as a resistive divider, but I lost that ratio when I threw in the integrator, since that turned the node from a divider into a summing junction--good catch.

I can get your results with no integrator at all--just chop it out, use my original resistor ratio, and the harmonic content is the same.

I still suspect a line-segment approximation using the integrator is much better, since the harmonic content going into the filter is sooo much better, but I just can't think about it right now.

Thanks for the comments and the tweaks.

Yes, but can you do *that* with six flip flops? I'd like to see it!

-- Cheers, James Arthur

, a

an

I couldn't resist a tweak myself--change my 3rd harmonic canceller resistor R11 to 300k into the integrator, as you noticed, and increase the integrating cap slightly to prevent the integrator clipping.

The 3rd harmonic is then gone, 5th harmonic is 57dB down, everything else is in the dirt, and the trick is done.

-- Cheers, James Arthur

, a

an

The URL I posted talks about 24 pulses, but I suspect that they aren't equally spaced - it probably needs programmable read only memory.

Six flip-flops is something of an under-kill when you can buy cheap plds - Farenll don't even stock the 32-macrocell Xilinx CoolRunner, and the 64-macrocell and 128-macrocell parts are tolerably cheap.

-- Bill Sloman, Nijmegen

ve

ge,

to a

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A trick is done. Capacitors aren't exactly ideal components, so your amplitude is loosely toleranced and becomes somewhat temperature dependent

-- Bill Sloman, Nijmegen

hree

ip-

And it would be trivial with a micro, just connect the coils between two pins and do: hh, hl ll lh ...

-Lasse

om

three

flip-

20

But a micro is an over-kill for this application. A dead-simple all-in- one-package over-kill, if you are familiar with a suitable micro, but still quite a lot more computing power than the problem needs, which is to say more transistors switching than you really need, which is an extra current drain, though apparently a fairly minor extra current drain with the right micro.

-- Bill Sloman, Nijmegen

We have a certain product where there's a microcontroller whose sole purpose in life is to... flash an LED. :-) OK, it does some "fancy" LED flashing, but still... I kinda cringe knowing that we threw in hundreds of thousands of transistors to flash an LED... but it's hard to argue with a part that's

--
The OP was clear in that he wasn't looking for bang-bangish into the
coils, but rather for three 10Hz _sinusoids_, separated in time by 120
degrees, in order to create a smoothly rotating magnetic field.

Shoulda used a 555. ;-)

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST),BillSloman

(PST)) it happenedBillSloman

(PST)) it happenedBillSlom=

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wrote:

(PDT),BillSloman

(PDT),BillSloman

(PDT),BillSloman

to

be

assertion until

about it.

serving

I don't have to supply the evidence that you're a liar. You do that well enough daily.

incompetent that

datasheet

is

No, it's not surprising that you tried to get away with yet another lie.

Clueless. If you could read, you would have learned that that datasheet replaced the FA, FB, and FC datasheets. When? Who cares? The part came out in early '89. I had them in my hands in January or February.

Again, more lies from Slowman.

I kinda prefer 74xx123's for blinking LEDs in response to fast trigger lines, actually. :-)

The software in that LED flasher micro was even written in C, amazingly enough.

But at least no RTOS.

Hey, I've finally been noticing all the Clear-Com Tempest units strapped to the college football guys as you had mentioned. Now *there's* a product that someone probably wanted to use an RTOS for!

---Joel