Pulse Amplitude Modulation (PAM) is the simplest form of pulse modulation. This technique transmits data by varying the voltage or power amplitudes of individual pulses in a timed sequence of electromagnetic pulses. In other words, the data to be transmitted is encoded in the amplitude of a series of signal pulses. PAM can also be used for generating additional pulse modulations.
If you look at this from a purely theoretical standpoint, the possible pulse amplitudes in pulse amplitude...
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Modulation is the process of varying some characteristic of a periodic wave with an external signals.
Modulation is utilized to send an information bearing signal over long distances.
Radio communication superimposes this information bearing signal onto a carrier signal.
These high frequency carrier signals can be transmitted over the air easily and are capable of traveling long distances.
The characteristics (amplitude, frequency, or phase) of the carrier signal are varied in...
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Traditional radio equipment works because all parties involved in the communication agree on what frequencies they will utilize. Traditional radio scanners work by scanning for and then listening to those frequencies.
Trunking radios, on the other hand, constantly renegotiate the frequencies utilized for the conversation. This allows for more efficient utilization of limited frequencies because each conversation does not require a dedicated channel. However, it also makes it very...
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Pulse Code Modulation (PCM) was pioneered by the British engineer Alec Reeves in 1937. The first transmission of a message using PCM was the SIGSALY voice encryption equipment used in high-level Allied communications during World War II starting in 1943.
The original primary application for PCM was to convert analog signals into digital format by taking samples of wave forms that fall within 8 to 192 KHz and converting them into a digital number 8 to 24 bits long. In short, PCM refers...
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Pulse Width Modulation, abbreviated as PWM, is a method of transmitting information on a series of pulses. The data that is being transmitted is encoded on the width of these pulses to control the amount of power being sent to a load. In other words, pulse width modulation is a modulation technique for generating variable width pulses to represent the amplitude of an input analog signal or wave. The popular applications of pulse width modulation are in power delivery, voltage regulation and...
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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...
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XM Radio is a satellite radio service. Satellite radio is a technology that for the most part has been around for many years. For instance, many television studios have been using satellites to beam TV signals from far away locations to viewers for decades, however satellite radio has been in operation in America since 2001.
Satellite radio is pretty easy to describe. The programs for satellite radio include music, talk shows, live sporting events and sport analysis shows. These shows are...
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We tend to take these little devices, which we find in our cars, offices, or homes, for granted. In other words, we are not at all bothered about how these songs, news and other information reaches our radios and hence to our ears. This article tries to take a sneak peep into the various steps that eventually lead to the voice that we hear from a speaker.
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...
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The F connector is a particular type of radio frequency connector that was developed in the early 1950's. Eric Winston is usually credited with the creation of the F connector, while developing cable television as an alternative to the broadcast television options of the day. What does the F Connector do?
The F connector provides an inexpensive connection for coaxial cables to communications devices and to other cables. While the cost of an F connector is generally less than many...
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When it comes to automobile security, the world is raving about car radio security codes. Most people who use vehicles will often find a car radio security code which is already in use. They may not, however, know about it because different car manufacturers term them differently. They are popularly referred to as radio code, theft-lock, unlock code, security code, anti-thief code, or decoding.
The purpose of the radio code is not to protect your vehicle itself, but as the name suggests...
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