A digital signal is a discrete signal representing data as binary values. It takes only two states: on or off, 1 or 0. There is no in-between. Digital signals are robust. Noise can be removed. Errors can be corrected. They can be stored, compressed, and encrypted. They are the language of computers.

Digital signals replaced analog for most communication. A phone call is digitized. A photo is a grid of numbers. A song is a stream of bits. The conversion happens at the edges. Microphones and cameras produce analog signals. ADCs convert them to digital. DACs convert them back.

Advantages of digital

• Noise immunity: errors can be detected and corrected
• Compression: data can be reduced in size
• Encryption: data can be secured
• Storage: data can be stored indefinitely
• Processing: data can be manipulated by computers

Digital signals are not perfect. They require more bandwidth than analog in some cases. They need synchronization. They can fail abruptly. But their advantages outweigh their costs. The world went digital. It is not going back.