Regarding Home Theater Audio Receivers

When contemplating how to put together a home theater system, one should not forget a crucial component to the audio and visual experience. Home theater audio and video are controlled by a receiver which is the central unit where the inputs and outputs of the home theater are based.
A home theater receiver combines the functions of three components. First, a tuner for AM and FM, in some cases high definition radio or Sirius Satellite or Internet radio. Second, a preamp that controls the audio or video source selected - Blu-ray play, DVD player, iPod etc. Last, a built in multi-channel amplifier that sends the surround sound signals to the speakers and also supplies power to the speakers.
The modern audio visual receiver (AVR) is a complex device, perhaps one of the more complex electronic devices in the home. It has a computer, amplifiers, audio signal processing chips, signal converter chips. Many AVRs have video processing chips as well. The main circuits in an AVR are: Power supply; Processor; Analog Audio; Digital Audio; Analog Video; Digital Video; Amplifier.
Each of these groups can be one or more circuit boards, or some could be combined onto a single circuit board. Care must be taken in the design such that circuits don't interfere with each other. There's also the need to deal with physical needs such as connector placement and air flow for proper cooling.
Stereo receivers have two channels of amplification, while AV receivers may have more than two. The standard for AV receivers is five channels of amplification. These are usually referred to as 5.1 receivers. This provides for a left, right, center, left surround and right surround speaker to be powered by the receiver. 7.1 receivers are becoming more common and provide for two additional surround channels, left rear surround and right rear surround.
AV receivers usually provide one or more decoders for sources with more than two channels of audio information. This is most common with movie soundtracks, which use one of a variety of different types of encoding formats.
As the number of playback channels were increased on receivers, more decoders have been added to some receivers. For example, Dolby Labs created Dolby Pro Logic IIx to take advantage of receivers with more than five channels of playback. With the introduction of high definition players like Blu-ray Disc and HD DVD, even more decoders have been added to some receivers. Dolby TrueHD and DTS-HD Master Audio decoders are available on many receivers.
All this information can be a lot to take in, however many web resources are dedicated to receivers alone. When choosing to revamp or build from scratch a home theater audio and video system, investigate the receivers offered to make the best choice for your personal theater needs