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Is important to use as high a percentage modulation as possible while ensuring that overmodulation does not occur. The side bands contain the information and have maximum power at 100% modulation. And AM transmiters attempt to maintain betwen 90 and 95 percent modulation as a compromise between efficiency and the change of drifting into into overmodulation.
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page 76 second paragraph of the MODERN ELECTRONIC COMUNICATION
By Jeffrey S.Beasley and Gary M.Miller
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∙ 12y ago
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Why you calculate percentage modulation?
For AM (amplitude modulation) signals, it is the ratio (x100 of course) of the modulating signal to the carrier signal. presumably FM calculations follow a similar course.
What is it called when a high percentage of the species on Earth dies off?
Mass extinction
Why do power plants emit such a high percentage of pollutants?
Because of the chemicals needed to produce energy.
What is the difference between the standard amplitude modulation linear addition and multiplication of signals?
In modulation u r sending two signals but their frequencies are sum or difference of carrier frequency and signal frequency.In addition u send two signals at two different frequencies so more interference.
What is 76g as a percentage?
as a percentage of what.
How do you xxplain Why modulation is desirable?
Explain why modulation is necessary or desirable.
In what stage modulation is done on high power amplitude modulation transmission?
In high power AM transmission, modulation is done at
What characteristic of an audio tone determines the percentage of modulation of an FM broadcast transmitter?
Only the amplitude of the audio tone determines the percentage modulation of an FM transmitter
What is high level AM modulation?
High level AM modulation is a type of modulation using class c (90 percent) amplifiers. The system uses medium power tubes or transistors and is bulky.
Explain Why high Quality factor is needed in RLC Circuits?
the higher the Q the narrower the bandpass or band-rejection. however high Q is not always desirable. for example in receiver IF stages too high a Q will filter out some of the needed modulation bandwidth, destroying signal information.
What are the advantages frequency modulation amplitude modulation?
Frequency modulation have some advantages over amplitude modulation, FM is not sensitive to the amplitude noise, and have high efficient use of transmitted power
What is lowlevel amplitude modulation and highlevel amplitude modulation?
low level amplitude modulation occurs when the carrier signal is first modulated and then amplified,whereas in high level modulation,the carrier signal is first amplified and then is modulated.
Why you calculate percentage modulation?
For AM (amplitude modulation) signals, it is the ratio (x100 of course) of the modulating signal to the carrier signal. presumably FM calculations follow a similar course.
What is high level modulator?
High level AM modulation is a type of modulation using class c (90 percent) amplifiers. The system uses medium power tubes or transistors and is bulky.
How velocity modulation is different from normal modulation?
As we know normal modulation is superimposing the wave with another carrier signal but the concept of velocity modulation is totally different, as The modulation in velocity of a beam of electrons or ions caused by passing the beam through a high-frequency electric field, as in a cavity resonator there is no concept of superimposition.
Is it desirable for a battery to have a high internal resistance?
No, it is desirable for a battery to have a low internal resistance.
What is the critical flicker fusion frequency?
By definition, the CFFF is "the highest or lowest temporal frequency, at a given percentage modulation, that can be resolved." (Schwartz, Visual Perception, 3rd ed.) In other words, the limits of distinguishing a flashing light from a steady one (at both the slow and fast end limits). Percentage modulation is calculated using the amplitude of the luminance of the light source, and the time-averaged luminance of said light source. In other words, the difference between the brightest/dimmest points in the cycle, averaged over the speed it takes to vary between the two points. Percentage modulation is used to calculate Relative Sensitivity, which is (1 / Percentage Modulation). For example: A lightbulb powered by Alternating Current (AC) is flickering. This is not visible to the normal human eye for two reasons (both variables in the definition of CFFF.) The temporal frequency of the AC in most American homes is 60Hz. The high temporal frequency cut-off for human sensitivity varies, and some cells are known to be sensitive to frequencies as high as 250 Hz, but for general daytime vision, it is lower than 60Hz. Also, the percentage modulation of a light bulb is low, since the change in brightness of the filament is very small. Relative sensitivity is the inverse of the percentage modulation. For flicker to be visible, a light source must have a relatively large change in level of brightness, and flicker at a rate within the human sensitivity range, somewhere between 2 and 50Hz. By definition, the CFFF is "the highest or lowest temporal frequency, at a given percentage modulation, that can be resolved." (Schwartz, Visual Perception, 3rd ed.) In other words, the limits of distinguishing a flashing light from a steady one (at both the slow and fast end limits). Percentage modulation is calculated using the amplitude of the luminance of the light source, and the time-averaged luminance of said light source. In other words, the difference between the brightest/dimmest points in the cycle, averaged over the speed it takes to vary between the two points. Percentage modulation is used to calculate Relative Sensitivity, which is (1 / Percentage Modulation). For example: A lightbulb powered by Alternating Current (AC) is flickering. This is not visible to the normal human eye for two reasons (both variables in the definition of CFFF.) The temporal frequency of the AC in most American homes is 60Hz. The high temporal frequency cut-off for human sensitivity varies, and some cells are known to be sensitive to frequencies as high as 250 Hz, but for general daytime vision, it is lower than 60Hz. Also, the percentage modulation of a light bulb is low, since the change in brightness of the filament is very small. Relative sensitivity is the inverse of the percentage modulation. For flicker to be visible, a light source must have a relatively large change in level of brightness, and flicker at a rate within the human sensitivity range, somewhere between 2 and 50Hz.
