Frequency modulation is a type of modulation where the frequency of the carrier is varied in accordance with the modulating signal. The amplitude of the carrier remains constant. The information-bearing signal (the modulating signal) changes the instantaneous frequency of the carrier. Since the amplitude is kept constant, FM modulation is a low-noise process and provides a high quality modulation technique which is used for music and speech in hi-fidelity broadcasts. In addition to hi-fidelity radio transmission, FM techniques are used for other important consumer applications such as audio synthesis and Read More

Satellite radio refers to a number of subscription-based radio broadcasting programs that are available in the US, Europe, and elsewhere that are dependent on satellites to provide mobile users with constant radio access. While terrestrial-based FM radio stations only provide radio broadcasts to a specific area, usually confined to the city they are located in, satellite radio is available even while the listener is moving between cities, states, and even countries. Satellite radio has been available for just over a decade, with the first artist ever broadcasted on satellite radio Read More

The decibel is a standard unit for measuring relative levels of current, voltage, or power. The decibel shows the ratio between the input and the output. Decibel is abbreviated dB. A minus sign before the dB indicates a loss and a plus sign or no sign at all before the dB indicates a gain. The Decibel Formula The decibel value of a change between input and output can be expressed utilizing the following algorithm: db = log10 Input / Output A Decibel Table Decibel Gain Ratio of Gain 1 1.3 Read More

HD Radio offers a new and better way to broadcast radio programs. The "HD" in HD radio is a trademarked brand name that's given by its developer and that doesn't stand for anything. HD Radio technology is developed without any intention to replace traditional FM and AM radio broadcast. HD Radio is currently being broadcast along with conventional FM and AM signals. The main difference of HD Radio compared to Amplitude Modulation (AM) and Frequency Modulation (FM) is the form of signal that it uses to carry information. Both AM Read More

Packet radio is a type of digital data transmission which is most commonly used to link two computers together. It is based on the X.25 protocol used previously by amateur radio enthusiasts. The new generation of this technology as it is used in packet radio is known as the AX.25 data link layer. Packet radio gets its name from the technology behind it. A type of technology known as packet switching is the primary driving force of packet radio. Packets, or small bits of information, are switched between nodes, such Read More

Those on a tight budget and would like to save possibly hundreds of dollars on installation costs and those who would like to customize their car audio system may want to install the car audio system themselves. Whatever the reason, it is quite easy to install a car audio system and here are some tips. What is a Car Audio System? Before installing a car audio system, it is best to define what a car audio system is. Usually, a car audio system includes a car stereo, sometimes referred to Read More

Although radios have become less and less of a household commodity due to television, Internet, and media players, they are still used on a daily basis by millions of people worldwide. We tend to take these little devices, which we find in our cars, offices, or homes, for granted, but rarely think about how they actually work. AM and FM radios are the common type of radios we find in our homes. They communicate by means of radio waves – hence the name – which is the lowest frequency of the Read More

A high-frequency alternator is an electrical device used for radio communications. It yields high-frequency, periodically alternating current that can go as high as 100,000 Hz for the purpose of producing stable radio waves. The History of High-Frequency Alternators By the first decade of the 20th century, wireless telegraphy was already in place and was no longer a novelty. The problem, however, was that the primary means of wireless communication – the spark-gap transmitter – was seen to pose major problems. For one, communications took place through the Morse Code system. Read More

A frequency changer makes it possible to change electricity moving at one frequency to another frequency. However, in order to fully understand what a frequency changer does, it is helpful to understand the frequency of electricity. The Frequency of Electricity Electricity doesn't move at one specific speed. In fact, it can move at many speeds. Some electronic devices require a set frequency or speed, while others can run proficiently at a range of speeds. The speed of electricity or frequency is measured in Hertz or Hz. One Hertz is one Read More

An attic antenna is one that is mounted inside of an attic in order to provide maximum range as well as protection from rain, snow, sun, wind, and animals. Attic antennas are rather common and provide quality reception for those who live in rural areas, away from most radio transmitters. While attic antennas do not have as good a reception as outdoor antennas, they are covered and do not detract from the home’s appearance. How Attic Antennas Work Except that they are mounted indoors, attic antennas use the same principles Read More