Distortion & Static

[ItsYikez]

What causes distortion and static? It's probably something simple, but I'm always fascinated when I hear static on the radio or see distortion in a video when I'm out of "the range"

[imatfaal]

What causes distortion and static? It's probably something simple, but I'm always fascinated when I hear static on the radio or see distortion in a video when I'm out of "the range"

 

You might not be old enough to remember but when the TV channels used to stop broadcasting at night you would get a white noise that filled the TV (it was called snow in England) - this was, in part, the highly attenuated and dispersed echo of the big bang. Well it was the TV picking up a portion of the Cosmic Microwave Background Radiation (or I believe signals generated by atmospheric interaction with the CMBR). Thermal Noise from within your system, mains hum at 50 or 60 Hz, and just stray and uninterpretable signals

[Velocity_Boy]

What causes distortion and static? It's probably something simple, but I'm always fascinated when I hear static on the radio or see distortion in a video when I'm out of "the range"

 

 

Both are simply the result of a weakened transmission signal. Or I should say, diminished or weakened reception. I guess it could be both. Whichever, in the case of both, the transmitted signal is not being recieved at the optimal level or strength by the recieving device. Be it a TV or a radio or a phone.

 

A note: when you referred to a distorted video I assumed you meant a transmitted one? I ask because we can of course see distorted videos on pre-recorded storage devices. Such as pixellation of video break-up on a DVD. Or a VHS tape. These would of course be caused not by a sub-optimal signal reception but by a flaw in the sotrage medium itself, i.e. a scratch on the DVD.

 

http://www.abc.net.au/reception/radio/radio_troubleshooting.htm

Edited April 12, 2017 by Velocity_Boy

[Bender]

Signal to noise ratio.

 

Analogue signals need to be amplified. This means you will also amplify the noise. If the ratio is high, you don't notice the noise. If it is low, the noise will become more important.

If there is no signal, the noise will be amplified to the level the signal would otherwise be.