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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.
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What are the different forms of amplitude modulation?
There are many types of modulation. A few examples...AmplitudeFrequencyPhase ShiftModified Frequency (MFM)Non Return to Zero Inverted (NRZI)Frequency Shift Keying (FSK)Other contributors - Please add to this list
What is the difference between a frequency modulator and a frequency mixer?
A mixer is a non-linear circuit that multiplies two signals together. If the inputs are sinewaves at frequencies f1 and f2 the output will contain signals at four different frequencies, f1, f2, f1 + f2, and f1 - f2. Some mixers may eliminate some of those outputs and post filtering can remove any other unwanted components. This is the way AM and SSB are typically generated. Modulation is a more general concept, and depending on the type of modulation you are doing, a mixer may or may not be involved in the modulation process.
What is the special symbol allowed in a variable name?
Any letter of the Greek or Roman alphabet, or any other alphabet can be used to represent a variable. There are also non-alpha symbols, for example for the Dirac constant (or reduced Planck constant).
When can't selection structures be represented in CASE?
When the case statement represents a non-constant expression or a non-integral type. The switch statement's expression must be of an integral type or of a type that can be unambiguously converted to an integral type.
Why is used just 2 or 4 poles in non salient pole rotor?
to force the generation machines ( generator in power plant) to work on constant speed which mean constant frequency for any power network n= 120 F / p
Which of the following modulation is non linear?
frequency modulation is non linear due to cross over term.
Why is Angle Modulation called nonlinear modulation?
angle modulation is called non linear modulation because the information is stored in phase of the carrier signal
Why angle modulation is called exponential modulation?
The reason it is called exponential (non-linear) modulation is that the information is encoded within the phase of carrier.
What is the difference between constant and non-constant motion?
Acceleration is the difference between constant and non-constant motion.
What is non-constant speed?
non-constant speed is when the speed for an object does not stay the same
What is non constant speed?
non-constant speed is when the speed for an object does not stay the same
Why noice level less in FM than am?
Frequency modulation differs from amplitude modulation. FM coverage distance is less with more clarity due to non interference with carrier waves.
What is mean by non isothermal columns?
isothermal means 'constant temperature' so to be non-isothermal means to have non-constant temperature.
What is square law diode modulator?
Methods of amplitude modulation can be put in the two categories namely Linear modulation methods and Square law modulation methods. Linear modulation method utilizes the linear region of the current voltage characteristics of the amplifying device that is transistor or electron tube. Square law modulation method utilizes the square law region of some current voltage characteristics of a diode or transistor or electron tube. A large number of linear modulation methods have been devised and have been used to varying degree. These methods are namely linear shunt plate modulation or anode choke modulation, linear series plate modulation, grid bias modulation, cathode modulation, suppressor grid modulation, screen grid modulation, collector modulation. Square law modulation circuits make use of non linear current voltage characteristics of diodes or triodes and are in general suited for use at low voltages. Important square law modulation methods are square law diode modulation and balanced modulator.
What is used to enclose a message?
An envelope encloses a written message (non-computer).
What is a fact for constant of variation?
It is non-zero.It is non-zero.It is non-zero.It is non-zero.
What is non numeric constant?
An algebraic letter. e/g 5a 'a' is a non numeric constant. Remember in algebraic , when a letter is given , it means that the value of the letter is a constant, but the value is unknown .
