Pi vs Tau

You might want to check out Vi Hart's videos...

The one about Pythagoras is a hoot too!

George H.

I don't see how having to use 2/tau would be easier than using 2 pi. Alot, alot of things are 2 pi. I realize that.

Why not just use both ? Or are they running out of Greek letters or something ?

Pythagoras

Those are both fun! Mikek

Sometimes it's more convenient to work in radian frequency instead of hertz, e.g. when designing PLL loop filters.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Or just do it all with macros. My latest OpAmp excess-phase solver (2-point... I'm working a 3-point which will find that extra pole not visible in the LoopGain plot)...

• C:\Projects\Expments\LoopGain\PhaseMaker.sch

• Schematics Version 15.7.0

• Mon Jun 23 12:52:55 2014 .PARAM DEGREES1=45

• DEGREES2=60

• THETA1={DEGREES1/180*pi}

• THETA2={DEGREES2/180*pi}

• .PARAM F1=11Meg

• F2=12Meg

• OMEGA1={2*pi*F1}

• OMEGA2={2*pi*F2}

• NUM={TAN(THETA2/2)/OMEGA2-TAN(THETA1/2)/OMEGA1}

• DEN={TAN(THETA2/2)*OMEGA2-TAN(THETA1/2)*OMEGA1}

• Y={NUM/DEN}

• X={TAN(THETA1/2)*(1/OMEGA1-Y*OMEGA1)}

** Analysis setup ** .ac DEC 101 10 100Meg .OP

• From [PSPICE NETLIST] section of C:\OrCAD\OrCAD_15.7i\tools\PSpice\PSpice.ini: .lib "C:\PSpice\SymbolLib\mylib.lib" .lib "C:\PSpice\SymbolLib\nom.lib" .INC "PhaseMaker.net"

**** INCLUDING PhaseMaker.net ****

• Schematics Netlist * R_R1 N_1 0 1K R_R2 N_2 0 1K E_E1 0 N_4 N_3 0 1 V_VAC N_3 0 DC 0V AC 1V L_LXP N_4 N_5 {sqrt(Y)} C_CXP OUT N_5 {sqrt(Y)} R_RXP N_3 OUT {X/(sqrt(Y))} V_V1 N_1 0 {sqrt(Y)} V_V2 N_2 0 {X/(sqrt(Y))} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

I'm talking about an old-fashioned method called "algebra". ;)

It's not an issue with computers.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

I did it first in "Algebra", then entered it onto a schematic to automate it (and eliminate the by-hand errors)... it's part of my toolset for behavioral modeling of OpAmps.

You'll note, if you follow thru... it's just the step-by-step solving of two simultaneous equations... for a tailored all-pass. Next tool will be for finding the unknown (far-out) pole location plus the excess phase term... solving three simultaneous equations in phase versus frequency... better detail than from gain data. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Mike Keith said, "thinking in terms of pi is like reaching your destination and saying you're twice halfway there."

..snip....very long URL that Aioe complained about We seem to get stuck with our conventions.

Mikek

so that means given a set of equally separated parallel lines on the floor and a stick that is exactly that separation distance in length. Upon throwing the stick out onto your floor, the probability of landing on a line is now going to be 2 over tau? We can't use 1 over pi anymore?

Someone PLEASE look up that statistic!

Think about the ramifications for first contact with aliens as well.

There we are, transmitting Pi in binary, and the aliens shake their heads (or whatever is their anatomical equivalent) in bafflement, decide we're deranged, and go home.

Sylvia.

Or exterminate us in fear of galactic contamination!

Jamie

No, that's why they dropped *you* off here, a form of exile.

they night just decide we misplaced the point, the two numbers are rather similar.

--
umop apisdn 


--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

I was wondering who'd notice that - I didn't want to spoil the story.

In practice, I doubt one would even bother with the point (which raises the issue of how to represent it). Just send the binary digits. If the aliens are worth knowing, they'll figure it out pretty quickly.

Sylvia.

More likely the opposite. Should planet Earth ever be visited by genuine aliens, we would likely follow the traditions of our ancestors. Something like "kill them and eat them".

However, the real problem is communications. It is quite true that any sufficiently advanced communications technology is indistinguishable from noise (also known as spread spectrum). An advanced alien civilization is unlikely to use crude modulation schemes like AM, FM, CW, etc. Were they to detect our crude modulation schemes, endlessly sending Pi, my guess is that they would consider us rather primitive. Endless repetition is a sign of madness, not intelligence, which they will surely deduce. The alien diplomatic protocol would probably require that they ignore us for a few hundred solar revolutions until we become sufficiently advanced to provide an intelligent and non-repetitive discourse.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

That's not the prevailing opinion. If they come here to colonize, they won't be the least interested, and will exterminate the human race..

Glad you could join the party, you fit right in.

Jamie

I can't see why. If they're remotely intelligent themselves, which seems likely given the circumstances, they'd have already examined the problem of communication on first contact. They might even have faced the problem on multiple occasions. They'd surely have realised that math is the obvious starting point, with mathematical constants like Pi and e, being easy to express and recognise.

On receiving an amplitude modulation of Pi in base 2, they should reply with something like e in the same form.

Of course, this assumes they're interested in communication. If they're not then the mode used in attempted communication really doesn't matter.

Sylvia.

ok happy Tau day then ;)

Cheers

The availability of RF spectrum is essentially limited. Wasting it on broadcasting endless repetitions, instead of sending something useful, would probably be considered pollution by an advanced civilization capable of receiving it, and which has probably run out of spectrum long ago.

Incidentally, in spread spectrum, narrow band noise sources, such as the AM or CW transmission of Pi, are eliminated in the receiver when de spreading. Accidental fly-by reception by a passing flying saucer on their spread spectrum based receiver is unlikely. Therefore, any alien civilization that might be expected to hear our narrow band transmissions will probably need to build an antique dedicated receiver to hear it.

Sending Pi in binary assumes that the advanced alien civilization uses or recognizes a binary number system. They could have advanced to quantum computing, where devices have states other than just zero or one. They may have developed a number system based on tri-state logic, where the available values are 0, 1, and open. Should they be able to modulate time, the added dimension would also provide a 3rd state of 0, 1, and when.

They also could have advanced quite nicely without a binary number system. For example, Roman numerals do not include a zero, and like the Inca civilization, which had no written language. Or, the alien politicians could have gained control over science and mandated that Pi is equal to exactly 3.0.

True. But if they remotely experienced in communicating with other intelligences, they're also likely to have had some rather bad learning experiences. I would suspect that they have a minimum acceptable criteria for initial contact, and a protocol for minimizing conflicts in place. One such criteria would probably be the degree of advancement of the aliens (that's us). Were the aliens excessively advanced, the visitors would likely to have been defeated in a short battle, killed, and then eaten. Were they of equal technical abilities, there would be little to learn from them and therefore not worth contacting. Were they technically retarded, as in a civilization unable to think of something beyond mindless repetition of Pi, it's either a trap to make them appear technically retarded, or we will become a burden for the aliens, where we are put on welfare until we can be brought up to speed. My guess(tm) is that the only criteria for acceptable contact is if we have something that they want, and that we are sufficiently advanced to defend it. Acting like idiots by repetition is not going to impress any potential buyers. Transmitting advertising and spam would be more effective.

Too easy. Sending a raster scan image, such as a 1 level fax picture, might be better. Send Pi if you must, but include something intelligent as a payload.

Pretend for a moment this was done at audio frequencies instead of RF. You fire off a megawatt megaphone belching primitive repetitious on/off keyed blasts of narrow band tones around the neighborhood. How would you react? Probably not very favorably and likely with retaliatory suppressive fire. It's like attempting to meet the neighbors by dumping sewage in their front yard. An advanced civilization will probably treat RF spectrum as a valuable resource and not take kindly to us trashing it.

If they're genuinely interested, it might more of an exercise in bureaucracy. Do they have the patience, resources, and capital to support a backwards civilization like ours? It's like the conquerors problem. After the conqueror pillages and takes over another town or civilization, they are eventually obligated to pacify, stabilize, and eventually maintain their conquests. If they lack the resources to do so, they invariably end up with a revolt. If this alien civilization has had some bad experiences in past visits and conquests, they might be rather hesitant to take on new responsibilities.

Bottom line: It pays to advertise and mindless repetition does not provide the required image.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558