The History of Radio and Television (Part 1)
... • In the United States, government may fund
electronic-media experiments, but it’s up to
business to apply the results.
• The key to telecommunications is that
electromagnetic energy can be transmitted
between two points.
• The early stage of media development is a
process to which many people contr ...
The Fundamentals of Ham Radio and Emergency Communications
... This caused a problem as more people started to use radio technologies especially in the cities
where several radio operators could live within a few blocks from each other. the radios created
lots of radio frequency (RF) interference, and the receivers would pick up anything. To fix the
problems, c ...
In-band on-channel (IBOC) is a hybrid method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency.By utilizing additional digital subcarriers or sidebands, digital information is ""multiplexed"" on an AM or FM analog signal, thus avoiding re-allocation of the broadcast bands. However, by putting RF energy outside of the normally-defined channel, interference to adjacent channel stations is increased when using digital sidebands.IBOC does allow for multiple program channels, though this can entail taking some existing subcarriers off the air to make additional bandwidth available in the modulation baseband. On FM, this could eventually mean removing stereo. On AM, IBOC is incompatible with analog stereo, and any additional channels are limited to highly compressed voice, such as traffic and weather. Eventually, stations can go from hybrid mode (both analog and digital) to all-digital, by eliminating the baseband monophonic audio.