Trigonometry terminology

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

Just find a good machinist friend and have him cut you a custom heavy platter for your cheaper drive, and then suspend it from rubber bands (the entire turntable) instead of putting it on a stand or floor connected hard mount.

That's as pro as it gets. All you need to do is decide on material(s) and construction. Get the mass right and you excede their methods. Press a nice, sintered bronze bearing into it and slide it onto a hard, micro-polished center shaft, and knock 'em all dead.

Of course, my $80 plastic POS sounded just as good, as long as you played it from another room than the one with the sound playback, and put a nice $150 Ortofon cartridge on it (1984 dollars). It made scratched recordings sound good. Best cartridge I ever owned/used.

** Go f*ck yourself !!!!

You PIG ignorant, retarded, stinking TROLL !!!!!!!!!!

"Phase locked" implies to me that (a) some sort of PLL is involved, which may be true but is not inherent in the idea of two sine waves of different amplitudes and phases but the same (average) frequency.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

Phil Hobbs wrote in news:q3ih0r$fn$ snipped-for-privacy@dont-email.me:

The military uses both 1 pps and 10MHz and even has timestamped pings that get sent. Everything else can get referenced to that for synching, etc.

quote:

10MHz is a frequency reference, PPS is a time reference its an important distinction.

You use 10 MHz to discipline the oscillators in connected equipment so that they having matching and accurate frequency. You use PPS to coordinate time (As in wall clock) between devices, often in connection with a UTC time value emitted via the RS232 port on the GPSDO.

The PPS signal is already synchronous to the 10MHz clock in such a way that all connected devices will sample a PPS edge on the same 10MHz clock edge. /quote

In a GPS receiver, the prime signal is the 1 PPS pulse. A 5 or 10 MHz oscillator is often phase locked (or "disciplined") by the 1 PPS.

What's interesting is that the 10 MHz does not usually have a defined phase relationship to the 1PPS. In fact it can't. There could be

9,999,999 or 10,000,002 cycles of 10 MHz between two 1PPS ticks, and the 1PPS rising edge can wander across 10 MHz cycles.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

phase locked does not specify frequency. In fact one of these days, probabl y this year... Since the audiophiles seem to like second harmonic distortio n in their single ended triode amps, I want to see what the phase relations hip does to the sound. In generally the second harmonic pollution is locked

fifty grand for a turntable is insane. They're starting to approach the co st of the lathe that cuts the record.

"Phase locked" is entirely neutral about how the two different waveforms g et to have the exactly the same (instantaneous) frequency. Since one way of visualising frequency is as the rate of rotation of the complex voltage ve ctor, one can talk about an instantaneous frequency.

--
Bill Sloman, Sydney

Phil's ideas about what "phase locked" might imply are trifle daft, as his idea that Jeroen's situation might involve an "average" frequency - in Jer oen's case the instantaneous frequency is to be identical for both signals.

GPS receivers wander around, which automatically messes up their phase rela tionship to the notional 10MHz reference frequency that the receiver infers from the real signals it gets from satellites whizzing overhead.

This is a long way from Jeroen's original post.

--
Bill Sloman, Sydney.

heavy platter..."

I know a few people who can do that.

material(s) and construction."

Yeah, piece of cake...

Get a Dual 12XX series. They are excellent at that and I got a secret forya. If you get feedback, change the absolute phase of both speakers. If you get the feedback you are going to get the feedback but the absolute phase determines at what frequency.

I had the Audio Technica AT13Ea wit the 2X7 hyperhyper elliptical. Silky smooth highs. Flat from 10Hz to 30,000Hz. The Ortofon might be better but I didn't see one locally so I bought the Audio Technica.

scratched recordings sound good."

I found conical styli in cheap cartridges to be better at f***ed up records, but I never owned an Ortofon so I can't say.

John Larkin wrote in news: snipped-for-privacy@4ax.com:

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It is like the grid and all synching to 3600 rpm to get 60 cycles. It wanders small amounts but ends up staying fully synched.

So the thing is meant to guage long term points within systems meant to work together. The bigger the distance between components the more it needds to be there.

In a 14 rack stimulator for the F-35 having over 1000 channels, all synched up and combined such that events stimulated and subsequnetly "read" by the aircraft sensors is occurring and being recorded at known points in time synched to within nanoseconds of each other at the big anechoic chamber down at Hughes.

Each rack had 9 4U devices with 16 channels in each all fed into a central 5U combiner which then feeds all of those to yet another rack where all of the event logging and stimulus gets calibrated out.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

I never made any comparisons. It was my first (and only) turntable aside from the '60s era Grey speaker cabinet that opens up into a 'record changer'. Yeah those 'changed' your records for you.

But that one I got was given to me by my Boss' son at a place I worked at. He was pretty well to do, and it already had that cartridge on it. He also sold my my favorite car. My first year model, 1970 Chevrolet Monte Carlo in Plum (burgundy) Vinyl top... for only $35! I loved that car.

This particular phrase, yes. I'll be going into frequency-domain and time-domain reflectometry, the relation between the two and some pros and cons of each. My target audience is mathematically sophisticated, which is why I have to get my terminology right, but they have limited knowledge of electronics.

Jeroen Belleman

No, it's simulated because he's simulating a return from an unmatched termination with a synthesized signal.

noun imitation or enactment, as of something anticipated or in testing.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

No, it is "stimulated" because it is a reflection you are observing and that had to be generated by the initial wave, that is the very definition of stimulation.

It matters not whether the 'signal' was "synthesized" or not. It matters not the termination. The fact that there is a reflection makes that reflection a stimulated signal and your observation of it is "reflectometry".

You may think that you "simulated" the signal because it was "synthesized", but your 'simulated' signal STIMULATED the circuit it was fed into and observed operating on. That 'circuit' is your 'unmatched termination'.

He is simulating the signal with which he is STIMULATING a return event with. One observes the return event data.

Again, that is the very definition of circuit stimulation.

Sorry, but it is a common mistake.

or put a sheet of something heavy on the platter. I'm not sure it's an ideal solution though.

A Technics deck is as pro as it gets - pro does not mean best quality.

I got a bunch of Ortofons, pointy things that came in plastic cylinders, never was a fan. I see they've got even pointier since then. Shures were always my fave.

NT

On Feb 6, 2019, Don Kuenz wrote (in article ):

_Coherent_ is correct, and it applies to reference signals generated from one another by frequency multiplication or division. The key is that the ratio of the rates of phase advance is constant. In the case of a signal and a frequency-doubled (or -halved) version of the same signal, that ratio is exactly two.

All correlated signals are coherent, but not all coherent signals are correlated. A signal and a frequency doubled version of that signal are coherent, but are uncorrelated.

The original definition of coherent was simply that coherent beams of light could be made to interfere and cancel. This was subsequently expanded to handle such things as frequency-doubled light.

Useful ref: "A unifying view of coherence in signal processing", William A. Gardner, Signal Processing, Volume 29 Issue 2, Nov. 1992, Pages 113 - 140.

Joe Gwinn

Thanks Joe, Don. To me, 'coherent' had the stronger meaning of 'same phase', but I see now that that was too restrictive. It looks like it's a winner then. Thanks again.

Jeroen Belleman

Yes, you are uncommonly sorry. You are also a genetic mistake.

On Feb 10, 2019, Jeroen Belleman wrote (in article ):

By the way, while in the above example the constant ratio happens to be an integer, this is not required. It can be any real number, and is often a rational number.

Joe Gwinn

John S wrote in news:q3q8ra$dpd$1@dont- email.me:

testing.

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Leave it to a twerp whom constantly makes such immature posts to do so yet again.

How UNscientific of you, dork boy.

Injecting a signal into a circuit IS STIMULATION.

Too bad you are such a bullheaded putz.