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What is the most commonly used quadrature amplitude modulation?
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What does am frequency stand for?
AM stands for Amplitude Modulation. In theory, amplitude modulation could be applied to a radio signal on any frequency but the AM band on most domestic radios stretches from 530 to 1700KHz.
What is the difference between amplitude shift keying and AM modulation?
Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a http://wiki.answers.com/wiki/Radio http://wiki.answers.com/wiki/Carrier_wave. AM works by varying the strength of the transmitted signal in relation to the information being sent. Angle modulation is a class of http://wiki.answers.com/wiki/Analog_signal http://wiki.answers.com/wiki/Modulation. These techniques are based on altering the http://wiki.answers.com/wiki/Angle or http://wiki.answers.com/wiki/Phase_%28waves%29 of a http://wiki.answers.com/wiki/Sinusoidal http://wiki.answers.com/wiki/Carrier_wave to http://wiki.answers.com/wiki/Transmission_%28telecommunications%29 data. The two main types of angle modulation are: http://wiki.answers.com/wiki/Frequency_modulation (FM) in which the http://wiki.answers.com/wiki/Frequency is varied, http://wiki.answers.com/wiki/Phase_modulation (PM) in which the http://wiki.answers.com/wiki/Phase_%28waves%29 is varied.
What is an amplitude modulation transmitter?
Amplitude Modulation, AM, is a technique where a high frequency carrier of constant amplitude and frequency is modulated by a lower frequency signal. This modulation varies the amplitude of the carrier, and the resultant modulated carrier is what is transmitted. A typical carrier in the standard AM broadcast band is 550 kilohertz to 1.6 megahertz, while the modulating signal is audio, in a range less than 20 kilohertz.Demodulation involves tuning the centerpoint of the carrier and detecting the envelope of modulation, often with a peak follower such as a diode, capacitor and resistor. Very simple AM radios can be built with only a few components, typically with less than six.While there are several demodulation techniques, by for the most common is the superhetrodyne technique. Since selectivity and sensitivity are opposing factors, the RF stage of such a receiver generally trades selectivity for sensitivity, simply boosting the gain with a middle of the road semi-broad band amplifier. Then this is mixed with a local oscillator that is tuned to be exactly 455 kilohertz away from the desired carrier frequency. The mixed signal then is shifted to a center point of 455 kilohertz.This is followed by a very steep skirt band pass filter, the IF stage, which filters out everything but the desired shifted carrier. This is where the selectivity comes in, and since the IF stage is tuned to only one frequency, it can be highly optimized. Actually, the IF stage is three stages, each tuned to slightly different frequencies, so that the response curve, while having steep skirts, and centered at 455 kilohertz, still has the bandwidth necessary to cover the audio range needed.The output of the IF stage is then demodulated using some kind of peak follower, and the output is the original signal.If you analyze the frequency domain of the modulated carrier, you discover that there is a carrier, and two side bands. The carrier contains no information, and consumes about 67% of the total power, while each side band carries the exact same information, but each is backwards to the other.This has led to improvements in design. Sometimes you can suppress the carrier prior to the final amplifier in the transmitter. This gives you the ability to put more power into the side bands. The down side is that the receiver is more complex, and has to regenerate the original carrier and mix it with the suppressed carrier signal before then mixing it for the downshift into the IF stage.You can take this even further, by suppressing both the carrier and one of the sidebands, since all of the signal is contained in both sidebands. Of course, this makes the receiver even more complex.Some CB and Amateur radios are single sideband suppressed carrier, simply known as SSB, in order to boost range. Most broadcast stations are double sideband non-suppressed carrier, simply known as AM, in order to simplify the receiver. Different areas of the world use slightly different terminology, such as SSB-SC, but the intent is the same.
What is the most commonly used text input device?
A keyboard is the most commonly used tool for entering text into digital devices.
What is meant by non constant envelope modulation?
A constant-envelope modualtion is a modualtion scheme in which the amplitude of the modualted tone remains constant with time. Main advantage of such modualtion schmes is that they relax the linearity requirements of the power amplifier (PA) and hence a less linear and more efficient PA can be used. Most modualtion schemes are not constant-envelope. For example, BPSK, QPSK, 16-QAM are not constant-envelope. Few modualtion schemes such as GFSK are constant-envelope.
What is mean by the term amplitude modulation?
The term amplitude modulation, or also known as AM, is a method of impressing data onto an alternating current. This is most commonly used for transmitting information via a radio carrier wave.
What does am frequency stand for?
AM stands for Amplitude Modulation. In theory, amplitude modulation could be applied to a radio signal on any frequency but the AM band on most domestic radios stretches from 530 to 1700KHz.
What does frequency stand for?
AM stands for Amplitude Modulation. In theory, amplitude modulation could be applied to a radio signal on any frequency but the AM band on most domestic radios stretches from 530 to 1700KHz.
What does the AM in AM Radio stand for?
Amplitude Modulation (AM) and Frequency Modulation (FM) AM tuning changes the amplification size of the waves being received, FM tuning controls the frequency of the waves being received. As commercial radio rose from it's early form, the AM 'band' stood for years as the only type of radio available. As technology improved, engineers discovered that they could modulate 2 channels of higher quality sound inside of one carrier frequency. The Federal Communications Commission designated from 87 MHz to 108 MHz for the new FM format. And, with this, FM radio was born.
Which modulation technique is most prone to noise PWM or AM?
AM = Amplitude Modulation and is more prone to noise because the signal amplitude caries the intellegence, Noise changes this easily. PWM is Pulse Width Modulation and noise does not change the width of the pulses, though it may introduce other pulses. Therefore the original intellegence is still recoverable.
What is the difference between amplitude shift keying and AM modulation?
Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a http://wiki.answers.com/wiki/Radio http://wiki.answers.com/wiki/Carrier_wave. AM works by varying the strength of the transmitted signal in relation to the information being sent. Angle modulation is a class of http://wiki.answers.com/wiki/Analog_signal http://wiki.answers.com/wiki/Modulation. These techniques are based on altering the http://wiki.answers.com/wiki/Angle or http://wiki.answers.com/wiki/Phase_%28waves%29 of a http://wiki.answers.com/wiki/Sinusoidal http://wiki.answers.com/wiki/Carrier_wave to http://wiki.answers.com/wiki/Transmission_%28telecommunications%29 data. The two main types of angle modulation are: http://wiki.answers.com/wiki/Frequency_modulation (FM) in which the http://wiki.answers.com/wiki/Frequency is varied, http://wiki.answers.com/wiki/Phase_modulation (PM) in which the http://wiki.answers.com/wiki/Phase_%28waves%29 is varied.
What is difference between ask and am?
The most fundamental difference, I would say, is that Amplitude Modulation (AM) is a kind of Analog Modulation Technique (the modulation is applied continuously in response to the analog information signal) where Amplitude Shift Keying is a type of Digital Modulation Technique ( an analog carrier signal is modulated by a discrete signal, digital modulation methods can be considered as digital-to-analog conversion, and the corresponding demodulation or detection as analog-to-digital conversion. The changes in the carrier signal are chosen from a finite number of M alternative symbols).
Why is that amplitude modulation is mostly affected by man made interference than frequency modulation?
since man made devices always produce noise for other electronic devices and noise always add at the amplitudes of any wave.in the am,amplitude is varying w.r.t. the information or modulating signal so it is most prone to noise and hence affected most by man made devices
What property of a sound wave is most commonly associated with loudness?
I believe you're referring to amplitude.
Amplitude modulation compared to Pulse position modulation'?
Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent. For example, changes in the signal strength can be used to reflect the sounds to be reproduced by a speaker, or to specify the light intensity of television pixels. (Contrast this with frequency modulation, also commonly used for sound transmissions, in which the frequency is varied; and phase modulation, often used in remote controls, in which the phase is varied) In the mid-1870s, a form of amplitude modulation-initially called "undulatory currents"-was the first method to successfully produce quality audio over telephone lines. Beginning with Reginald Fessenden's audio demonstrations in 1906, it was also the original method used for audio radio transmissions, and remains in use today by many forms of communication-"AM" is often used to refer to the mediumwave broadcast band (see AM radio). Pulse-position modulation (PPM) is a form of signal modulation in which M message bits are encoded by transmitting a single pulse in one of 2M possible time-shifts. This is repeated every T seconds, such that the transmitted bit rate is M/T bits per second. It is primarily useful for optical communications systems, where there tends to be little or no multipath interference.
Which cellular system uses the most bandwidth efficient modulation?
I think it is Frequency Modulation with Phase modulation which it the most bandwidth efficient
How is information transmitted using waves?
In the most extreme case, you can turn the wave on and off completely; this is commonly used in Ethernet for example. You can also modulate some aspect of the wave, such as amplitude (amplitude modulation), frequency (frequency modulation) or phase (phase modulation).Let's consider turning the wave signal on and off. The simplest way to transfer information this way is to agree to send (for example) one bit every second; in that case, if the signal is ON during one second, that might represent a "1", and if the signal is OFF during some other second, that might represent a "0". In practice, much more than one bit per second is usually transmitted (for example, 100 million bits every second is typical, nowadays, for home Ethernet); and more complicated systems are generally used to encode the signal.
