Learning about Electrical signals
Learning about Electronics , signals , communication
Communication
Communication is sending information from one place to another.
In wireless communication, we don’t use wires or cables — instead, we use waves to send information.
Wave is simply a way to move energy or information from one place to another. Imagine throwing a pebble in a pond, ripples carry energy outwards
Waves in communication work in a similar way, but instead of water, they travel through air or space.
Electrons exchange virtual photons (which disappears fast enough such that we cannot detect it) and experience a repulsive force in space like ( every action has an equal and opposite reaction kind off ) to consider all these interaction we take in account electric field Electrons “talk” to each other by throwing invisible “balls” (virtual photons). When one throws a ball, it recoils, and when the other catches it, it feels the push. This back-and-forth exchange creates the repulsive force we observe as the action of the electric field.
A “field” refers to an area or space where forces can be felt. Also we can imagine it as an football field where electrons play
And at the special relativity level, we see that electrons and protons , they contract in the direction of the motion .. think of this as , at high speed a plane moving towards right direction gets compressed and things in opposites gets delayed and this relativity effect happen in objects and as they are made up of atoms they experience a force and this force on charge in an movement of electrons and protons is called Magnetic field.
Coiled wire and the forces it experiences
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Information in waves ?
How information encodes and travels in air ? Doesnt get lost ? penetrates through objects ? How far can that go?
1. Waves carry information in there characteristics ..
Amplitude (height of the wave) Frequency (how often waves repeat) Phase (timing of the waves)
AM Radio: Changes amplitude to encode sound FM Radio: Changes frequency to encode sound Modern digital: Uses combinations of these to pack more information
- $ travels $ travel in line of people standing close together and vibrating Low frequencies (like bass) travel farther and penetrate objects better High frequencies (like treble) travel shorter distances and are easily blocked
3. Actually, they do! Waves get weaker (attenuate) due to: Spreading out (like ripples in a pond getting smaller) Absorption by air/objects Interference from other waves Temperature and weather conditions
What is electromagnetic ?
Sunlight is an EM wave Electromagnetic waves to send information wirelessly. These waves are made up of:
Electric fields: Invisible “push” forces. Magnetic fields: Invisible “pull” forces. They work together and move through the air at the speed of light.
Imagine you want to send a message across a lake:
Digital Signal: You tap a wooden stick in the water in a precise pattern (e.g., tap-tap…pause…tap-tap-tap). The taps represent your message in 0s and 1s.
EM Wave: The ripples in the water are what actually carry your taps to the other side of the lake.
In the real world, the digital message (your taps) often rides on EM waves to travel from one place to another, like how Wi-Fi or mobile data works.
How does cellphones transmit sound and stuff ?
Your voice goes to microphone ( that is an analogue signal ) with the help of MEMS sensor and IC it gets converted to digital signal aka binary signal ( 0’s and 1’s) Then this binary signal is taken up by antenna to convert to EM wave
0 is low frequency and 1 is high frequency
Cellular tower, ( cell tower ) , each area is divided in hexagonal parts and each part has its own tower and frequency slot