Some Radio Guys .....
More correctly said is - "....the polarity of the output signal is inverted with respect to the input.
Do you want me to come around and slap this into this 'radio guy' ???.
The correct terms are 'Relative Phase' and 'Absolute Polarity' - two entirely different things actually.
Relative phase is signal delay or lead measured in degrees (or radians) with respect to a reference signal.
Absolute polarity is the sign of a signal WRT a system reference polarity.
Acoustic Absolute Polarity refers to in room sound wave polarity - IOW compression or rarefaction pulses.
A balanced system does not have two 'phases' - it has two signals that are inverted in sign WRT to each other.
I slap my apprentices for using wrong terminolgy, and then they don't forget.
Eric.
Not quite right - anti-phase is not a proper term.
More correctly said is - "....the polarity of the output signal is inverted with respect to the input.
Do you want me to come around and slap this into this 'radio guy' ???.
The correct terms are 'Relative Phase' and 'Absolute Polarity' - two entirely different things actually.
Relative phase is signal delay or lead measured in degrees (or radians) with respect to a reference signal.
Absolute polarity is the sign of a signal WRT a system reference polarity.
Acoustic Absolute Polarity refers to in room sound wave polarity - IOW compression or rarefaction pulses.
A balanced system does not have two 'phases' - it has two signals that are inverted in sign WRT to each other.
I slap my apprentices for using wrong terminolgy, and then they don't forget.
Eric.
Anti-phase
If I remember this correctly, and I am pushing my memory, this is typically used in discussions about antenna systems. Phasing is critical in these systems where you are using multiple elements to construct complicated systems to combine signals, combine amplifiers, combine elements, constuct directional paterns and such.
One would have to think pretty hard to make it analogous, though I suppose it is possible.
If I remember this correctly, and I am pushing my memory, this is typically used in discussions about antenna systems. Phasing is critical in these systems where you are using multiple elements to construct complicated systems to combine signals, combine amplifiers, combine elements, constuct directional paterns and such.
One would have to think pretty hard to make it analogous, though I suppose it is possible.
This whole thread reminds of the TV add that claims "x is 3 times less expensive than y" BUZZZ. X can be 1/3 as expensive as Y, but to be 3 times less expensive they would have to pay you to take it (ie X would end up having a negative cost).
By the way there are a couple of very good reasons why pro audio people keep using the term phase reversal instead of the correct term polarity reversal.
- The phase symbol fits easier on top of the little polarity reverse buttons on their mixers, +/- takes up more real estate. Given how crowded most large mixers are this is not a trivial issue.
- If you say polarity then any fool knows what you are talking about (we all use batteries). Sprinkling references to phase in your conversation adds a useful element of mystery and implies you hold esoteric knowledge. We all like to feel special after all.
Phil
By the way there are a couple of very good reasons why pro audio people keep using the term phase reversal instead of the correct term polarity reversal.
- The phase symbol fits easier on top of the little polarity reverse buttons on their mixers, +/- takes up more real estate. Given how crowded most large mixers are this is not a trivial issue.
- If you say polarity then any fool knows what you are talking about (we all use batteries). Sprinkling references to phase in your conversation adds a useful element of mystery and implies you hold esoteric knowledge. We all like to feel special after all.
Phil
Okay then, here's the newbie
First, some informal stats.
Ways to approach the issue
1) Semantically
2) Logically
3) Graphically
4) Historically
5) Mathematically
6) Psychologically
7) Empirically
8) Experientially
9) Cynically
10) Sorry if I missed you...
Ways to argue against another approach
1) See 1-9 above
2) See 10 above
I've noticed that the lesson is often in walking the proverbial mile in someone else's shoes, or not.
I think I'm not ever going to use either term again. I'll just say things like - Is that in reverse or backwards? Are you sure it isn't delayed somehow? What about flipping the wires? Wait, can you try that the other way around?
There needs to be a way to describe tolerances in language - kind of +/- indicator, more or less (excuse the quadruple pun). Just like with drawings for manufacturing, if I don't indicate a variance (oh, is that another word?) then I've asked for something absolute(ly) perfect, and so curiously, it inverts into a flaw.
Bear (polar?) in mind that every approach has it's defects. Some examples to debunk the more "precise" methods:
Mathematical - a little noise throws everything into chaos
Historical - ask yourself if the winner writes the history book or does the author of the history book determine the winner
Graphical - you forgot about polar coordinates (grizzly (sic) eh?)
Experiential - the event and its memory are the same
Empirically - Heisenberg
And finally, for the cynical - it's just a phase.
ensen.
PS: I'll bet half of all posts are to prevent loss of phase.
PPS: I prefer a good whine over beer. Maybe one of those ridiculously expensive Zinfandels please.
First, some informal stats.
Ways to approach the issue
1) Semantically
2) Logically
3) Graphically
4) Historically
5) Mathematically
6) Psychologically
7) Empirically
8) Experientially
9) Cynically
10) Sorry if I missed you...
Ways to argue against another approach
1) See 1-9 above
2) See 10 above
I've noticed that the lesson is often in walking the proverbial mile in someone else's shoes, or not.
I think I'm not ever going to use either term again. I'll just say things like - Is that in reverse or backwards? Are you sure it isn't delayed somehow? What about flipping the wires? Wait, can you try that the other way around?
There needs to be a way to describe tolerances in language - kind of +/- indicator, more or less (excuse the quadruple pun). Just like with drawings for manufacturing, if I don't indicate a variance (oh, is that another word?) then I've asked for something absolute(ly) perfect, and so curiously, it inverts into a flaw.
Bear (polar?) in mind that every approach has it's defects. Some examples to debunk the more "precise" methods:
Mathematical - a little noise throws everything into chaos
Historical - ask yourself if the winner writes the history book or does the author of the history book determine the winner
Graphical - you forgot about polar coordinates (grizzly (sic) eh?)
Experiential - the event and its memory are the same
Empirically - Heisenberg
And finally, for the cynical - it's just a phase.
ensen.PS: I'll bet half of all posts are to prevent loss of phase.
PPS: I prefer a good whine over beer. Maybe one of those ridiculously expensive Zinfandels please.
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