Communication

Communication devices are a wide variety of parts used in electronic communications systems. They are elements of the information interface, the channel processing and transceiver subsystems. Communication devices may transduce physical effects containing information into electronic signals. They may engage in processing electronic signals between the local transducer and the transceiver subsystem, including encapsulating information in a format to facilitate transfer. They may also be part of the conversion and transception of data over the electromagnetic spectrum.
Communications systems can include wired systems where the physical transfer medium is a cable or power line. They can be wireless systems including HF equipment through to microwave broadband systems. They may also be photonic transceivers using infrared LED interfaces or even Optic Fiber. They are usually broken down into two main categories—digital and analog. Digital communication transmits and receives data that is modulated as an encoded binary sequence where symbols are directly represented by a combination of amplitude and phase. Analog systems transceive data as a continuous modulated signal that is up or down converted between the high-frequency band and the original unmodulated base-band signal.

Transducers used in communications systems include microphones and speakers for audio, ultrasonic transducers, image sensors or even special purpose environmental monitoring, geolocation, and movement sensors. Many systems communicate control events and data. For example, remote control equipment. Voice and image data can require compression or expansion to allow it to fit within the transmission mediums bandwidth constraints using encoder or decoder devices, for example h.264 encoders.

Channel processing may incorporate encapsulation of data into frames which may include different layers of datagrams which include flow control information (headers) with checks on correctness (CRCs), error correction (FEC), encryption (Ipsec) and channel control information. Such devices include Ethernet MACs, Digital Signal Processors (DSP), Modems and even general purpose CPUs running services like TCP/IP.

Transmitter and receiver oriented devices include integrated circuits and passives specifically designed to meet the needs of the communications standard required to transceive across the physical medium used. This includes the amplifiers, oscillators, VCXOs, filtering components, transformers, connectors and even special purpose low noise power supplies.