Any and all increases in digital mode usage creates a higher noise floor for every RF communication service.
I won't go fully into it but here goes in as few words as possible.
Modulation theory and frequency "creation" is simple. When you modulate in AM, for instance, you use two sinewaves.
If the information (modulation) is 100%, ALL the power is gone from the carrier frequency and is contained in two symmetric sidebands.
If we create ONE digital "change of state", that is, one "bit" of data, turning on and off (completely) creates sidebands which
basically attempt to put some energy on ALL frequencies from DC to light.
This is because of the square shoulder to the waveform of the "full-on full off" digital.
As opposed to the well-behaved nature of information (AND ENERGY) into two clean sidebands in analog.
Now multiply that by your number of sidebands per station, AND your modulation rate, and there's no doubt what is raising
the noise floor.
It's no problem in a cable or fiber optic, where bandwidth can be endlessly created simply by running more of it.
And I fully approve of digital in such environments.
But there is only one "ether", and the fact is, you'd rather have your lamp dimmer than a useful radio.
As more and more devices create ever more noise, I expect things to get really ugly when the solar cycle comes back to the upswing.
It's a very big problem in radio, permitting full-out garbage to spewed as long as it's got useful information in the pollution.
Discontinuous current devices are the bane of radio, and once upon a time the FCC acted to stop (or noise suppress ) such devices.
But don't listen to a radio engineer, listen to the salespeople, right?
Have a nice digital day.
I won't go fully into it but here goes in as few words as possible.
Modulation theory and frequency "creation" is simple. When you modulate in AM, for instance, you use two sinewaves.
If the information (modulation) is 100%, ALL the power is gone from the carrier frequency and is contained in two symmetric sidebands.
If we create ONE digital "change of state", that is, one "bit" of data, turning on and off (completely) creates sidebands which
basically attempt to put some energy on ALL frequencies from DC to light.
This is because of the square shoulder to the waveform of the "full-on full off" digital.
As opposed to the well-behaved nature of information (AND ENERGY) into two clean sidebands in analog.
Now multiply that by your number of sidebands per station, AND your modulation rate, and there's no doubt what is raising
the noise floor.
It's no problem in a cable or fiber optic, where bandwidth can be endlessly created simply by running more of it.
And I fully approve of digital in such environments.
But there is only one "ether", and the fact is, you'd rather have your lamp dimmer than a useful radio.
As more and more devices create ever more noise, I expect things to get really ugly when the solar cycle comes back to the upswing.
It's a very big problem in radio, permitting full-out garbage to spewed as long as it's got useful information in the pollution.
Discontinuous current devices are the bane of radio, and once upon a time the FCC acted to stop (or noise suppress ) such devices.
But don't listen to a radio engineer, listen to the salespeople, right?
Have a nice digital day.