Information is electronically represented as some energy that is changing, therefore we measure an on state (1) and an off state (0), to create a (0,1) binary representation of the information.
Now a static magnetic field by definition has a frequency of 0 Hz, so frequency modulation can't happen. But what if we modulate the amplitude? (Tesla), would that consist as a static field?
- Can an amplitude modulation work to send information from an electronic device that creates a magnetic field with constant frequency?
- What if the device is already electrically shielded, as this is a follow up to my previous question. If we already have a device that is sufficiently electrically shielded, can information leak out from the magnetic field via amplitude modulation?
I am specifically interested how can / if possible / information leak out from an electrically shielded device by modulating a magnetic field.
EDIT: I made the question more precise. Referring specifically to the relationship between amplitude modulation / frequency modulation, and a static magnetic field. I believe a magnetic field with 0 frequency is only static if the amplitude is constant as well, reading the answers below.