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April 17 Information
How do they make sure radio waves won't overlap each other?
We watch Televising by grabbing radio waves that carry a video signal representing moving images, along with a synchronized audio channel. How do they make sure this radio waves won't overlap each other?
Rizosome (
talk)
17:14, 17 April 2021 (UTC)reply
Three answers, depending on what you mean by "overlap";
If you are in a room with two light bulbs, how do you make sure the light waves won't overlap each other?
Different TV and radio stations are on different frequencies, and (in the US) the FCC makes sure that they don't interfere with each others signals on a particular frequency.
That's because the signal is strong enough to bypass the antenna circuit and begin to drive the speaker circuit directly. The purpose of the antenna circuit is to amplify a specific signal and send that amplified signal to your speakers. If the signal in the air is already stronger than the amplified signal from the antenna circuit, then it will be broadcast instead of your antenna signal. This is more pronounced with AM radio than with FM radio; indeed, with AM radio, you can build a simple receiver without a battery; if you're close to the transmitter it will broadcast the signal without any external power source at all; the RF signal is sufficient to drive a small speaker itself.
This page describes building simple radio receivers that don't require any power source. --
Jayron3214:05, 19 April 2021 (UTC)reply
For radio waves in vacuum, or air, or on the surface of metal, or in common insulators, the response is linear so that the
superposition principle applies. This means that the waves can be separated out again and can pass through each other without affecting each other. Some materials are
non-linear. (see
Nonlinear optics) These include semiconductors with junctions or some kinds of crystals. In these the waves can mix to make difference and sum outputs, and also harmonics. But the TV will make sure that these are only used by design and not by mistake. Baseball Bugs' example will be due to a non-linearity in the first stage of the receiver that is loaded beyond its design limit.
Graeme Bartlett (
talk)
12:47, 19 April 2021 (UTC)reply
Another answer:
Radio antennae use something called a
LC circuit, or
inductor-
capacitor circuits. Both electronic components have a certain
frequency, and when they are the same, the LC circuit enters a 'resonance' state, where the inductor and capacitor are synchronized. This leads to them receiving only a certain frequency of wave (see
LC circuit#Applications). This can tune the receiver to whatever frequency you want. I don't know if that's what you're asking, but there's my two cents.
Sungodtemple a
tcg fan
!!1!11!! (
talk)
14:07, 20 April 2021 (UTC)reply
Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a
transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the
current reference desk pages.
April 17 Information
How do they make sure radio waves won't overlap each other?
We watch Televising by grabbing radio waves that carry a video signal representing moving images, along with a synchronized audio channel. How do they make sure this radio waves won't overlap each other?
Rizosome (
talk)
17:14, 17 April 2021 (UTC)reply
Three answers, depending on what you mean by "overlap";
If you are in a room with two light bulbs, how do you make sure the light waves won't overlap each other?
Different TV and radio stations are on different frequencies, and (in the US) the FCC makes sure that they don't interfere with each others signals on a particular frequency.
That's because the signal is strong enough to bypass the antenna circuit and begin to drive the speaker circuit directly. The purpose of the antenna circuit is to amplify a specific signal and send that amplified signal to your speakers. If the signal in the air is already stronger than the amplified signal from the antenna circuit, then it will be broadcast instead of your antenna signal. This is more pronounced with AM radio than with FM radio; indeed, with AM radio, you can build a simple receiver without a battery; if you're close to the transmitter it will broadcast the signal without any external power source at all; the RF signal is sufficient to drive a small speaker itself.
This page describes building simple radio receivers that don't require any power source. --
Jayron3214:05, 19 April 2021 (UTC)reply
For radio waves in vacuum, or air, or on the surface of metal, or in common insulators, the response is linear so that the
superposition principle applies. This means that the waves can be separated out again and can pass through each other without affecting each other. Some materials are
non-linear. (see
Nonlinear optics) These include semiconductors with junctions or some kinds of crystals. In these the waves can mix to make difference and sum outputs, and also harmonics. But the TV will make sure that these are only used by design and not by mistake. Baseball Bugs' example will be due to a non-linearity in the first stage of the receiver that is loaded beyond its design limit.
Graeme Bartlett (
talk)
12:47, 19 April 2021 (UTC)reply
Another answer:
Radio antennae use something called a
LC circuit, or
inductor-
capacitor circuits. Both electronic components have a certain
frequency, and when they are the same, the LC circuit enters a 'resonance' state, where the inductor and capacitor are synchronized. This leads to them receiving only a certain frequency of wave (see
LC circuit#Applications). This can tune the receiver to whatever frequency you want. I don't know if that's what you're asking, but there's my two cents.
Sungodtemple a
tcg fan
!!1!11!! (
talk)
14:07, 20 April 2021 (UTC)reply