Digital Communication

What is a carrier wave?

An electromagnetic wave whose amplitude of frequency is modulated to transmit information.

What is sampling rate and what does the sampling rate of a pixel determine?

The number of samples per second; it determines the quality of the image.

What is the definition of analog?

Smooth and continuous data.

How can a digital wave become more like an analog wave?

Increase the sampling rate to a very high frequency.

What are the advantages of digital waves?

\-Better resolution + sound fidelity

\-Less effected by sources of noise

\-Can be stored, copied, and transmitted more reliably

\-Uses available broadcast frequencies more efficiently

\-Provides more sound and video choices

What is the first step to sending a text message?

Each text message is a character, which the phone translates into a binary sequence (a series of 1s and 0s).

What is the second step to sending a text message?

A carrier wave is modulated from the binary sequence (code). The digital electromagnetic wave carries the message to the friend's phone.

What is the final step to sending a text message?

The phone demodulates (decodes) the carrier wave in order for the message to be read.

What are some examples of analog media?

Radio, film, and traditional audio recording.

What is an image made out of?

Pixels.

What is a video?

A sequence of images displayed very rapidly, usually 30 images per second.

How does a phone transmit sound?

The phone translates words into a series of binary pitch and volume values, which happens in the microphone. The phone attaches the binary message to a digital carrier wave, just like what happens when word messages are sent. The receiving phone then demodulates the message so the voice can be heard.

What is one advantage of digital signals?

It eliminates noise in the signal. Computers can clean up digital data and improve the signal quality.