COMMS - ECE 412

Invented the first telegraph

Who predicted the existence of electromagnetic waves?

Who were the first to transfer voice over a device? (telephone)

Who confirmed the existence of electromagnetic waves?

Produced the first wireless radio signals through the earth's atmosphere.

The first station to broadcast AM signals.

Patented frequency modulation (FM).

___________ is a logarithmic unit that can be used to measure ratios of virtually anything.

A negative dB indicates that the output power is greater than the input power. It indicates a power gain or amplification.

The fundamental purpose of an electronic communications system is to _________ from one place to another.

A ___________ is a collection of one or more electronic devices or circuits that converts the original source information to a form more suitable for transmission over a particular transmission medium.

_____________ is any unwanted electrical signals that interfere with the information signal.

The process of changing one or more properties of the analog carrier in proportion with the information signal.

Signals from two or more sources are transmitted at the same time, they would interfere with each other

Assigns frequencies and communications services for free-space radio propagation

Is an international agency in control of allocating frequencies and services within the overall frequency spectrum.

_________ also known as surface waves. They follow the curvature of the earth and can travel distances beyond the horizon.

It consists of electrical signals that originate from outside the Earth’s atmosphere and is also called deep-space noise.

High intensity sporadic disturbances caused by sunspot activity and solar flare-ups. This pattern repeats every _____________.

It is caused by the random arrival of carriers at the output element of an electronic device, such as a diode, field-effect transistor, or bipolar transistor.

Unwanted sum and difference frequencies