Combining high frequencies to get a large frequency

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Discussion Overview

The discussion revolves around the concept of combining high frequencies to achieve a larger wavelength or lower frequency. Participants explore the implications of wave interactions, particularly in the context of interference patterns and applications in various fields such as radio and microscopy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants question the meaning of "large" frequency and suggest it may refer to achieving a low frequency or increased wavelength.
  • There is a discussion about whether two waves interact when they meet and the nature of that interaction.
  • One participant asserts that it is possible to combine high frequencies to achieve a larger wavelength, citing applications in radio technology and piano tuning as examples of this phenomenon, referred to as beat frequency.
  • Another participant introduces the term "heterodyning" as a technique related to the discussion, noting its application in microscopy to exceed classical resolution limits.
  • A later reply shares a personal experience with fiber-optic technology, mentioning observations of interference patterns and their potential relevance to microscopy and heterodyning.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of "large frequency" and whether combining high frequencies can effectively increase wavelength. The discussion includes both supportive and questioning perspectives, indicating that multiple competing views remain.

Contextual Notes

Some claims rely on specific definitions of frequency and wavelength, and the discussion does not resolve the mathematical or conceptual details surrounding wave interactions and heterodyning.

kmarinas86
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"Combining high frequencies to get a large frequency"

"Combining high frequencies to get a large wavelength"

Is this possible? There will be constructive and destructive interference, but can there be anything that increases the wavelength?
 
Last edited:
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What is a "large" frequency?
 
billiards said:
What is a "large" frequency?
I think he means "to get a low frequency" and "anything that increases wavelength".
 
DaveC426913 said:
I think he means "to get a low frequency" and "anything that increases wavelength".

Ya... that's what i meant ... don't know why i didn't see that =p
 
Well, do 2 waves interact with each other if they meet? And if they do, in what level?
 


kmarinas86 said:
"Combining high frequencies to get a large wavelength"

Is this possible? There will be constructive and destructive interference, but can there be anything that increases the wavelength?

Yes it is and its quit common. Radios use this to bring rf frequencies down to audio f. Piano tuners use this to tell when they're approaching the right string tension. Pilots use it to sync up twin engines on boats and planes. It's call a beat frequency. I bet wikipedia.org has something on it. take a look.
alex
 


The technique is referred to as heterodyning.
 


Heterodyning is also beginning to be applied to microscopy, to move spatial frequencies beyond the classical resolution limit back into the exit pupil. One way is off-axis illumination, but there are several:

Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13081-6. "Nonlinear structured-illumination microscopy: wide-field fluorescence imaging with theoretically unlimited resolution.", Gustafsson MG.
 


Interesting..
When coupling a fiber-optic bundle image transfer block to a fibre-optic faceplate on an image intensifier, we used to rotate the part to a place where the Moire patterns and other effects were minimum.

I noticed once that as the planes of fibres came to line up with the faceplates (bundles of hexagons) structure, I could make in the interference patterns, a clear image of the boundaries, including broken interfaces and distorted joins. Also, I could get several versions of these, getting bigger as I approached "zero beat".

This was about 15 years ago. I wondered at the time whether the effect could be used for microscopy, and now, whether what I saw is part of this.

Heterodyning is also beginning to be applied to microscopy, to move spatial frequencies beyond the classical resolution limit back into the exit pupil. One way is off-axis illumination, but there are several:

Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13081-6. "Nonlinear structured-illumination microscopy: wide-field fluorescence imaging with theoretically unlimited resolution.", Gustafsson MG.
 

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