EngeeComms.DQPSK_ModulatorBaseband
Differential quadrature phase modulation.
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Description
The DQPSK_ModulatorBaseband system object performs signal modulation with usage of the differential quadrature phase shift keying method. The output signal is a modulated signal in the baseband. The input signal must be sampled in time.
To modulate using the differential quadrature phase shift keying method, follow the steps below:
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Create an object EngeeComms.DQPSK_ModulatorBaseband and set its properties.
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Call the object with arguments as if it were a function.
To learn more about how to work with system objects, see Engee system objects.
Signals with an integer value
If the property InputType property is set to Integer, the allowed input values are 0, 1, 2 and 3. In this case, the system object accepts the input signal as a scalar or column vector.
If the first input signal is m, the modulated symbol at the output will be of the form:
,
where is the phase shift.
If the subsequent input signal is also m, then the modulated symbol at the output is equal to the previous modulated symbol multiplied by .
Signals with binary value
If the property InputType is set to Bit, the input contains pairs of binary values. In this case, the system object accepts a column vector whose length is equal to an even integer.
More generally, if the property PhaseRotation is set to for some integer k, then the signal constellation has 2k points.
Syntax
Creation
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dqpskmod = EngeeComms.DQPSK_ModulatorBaseband()creates a system object to perform modulation usage of thedqpskmoddifferential quadrature phase manipulation method with by default properties.Example:
dqpskmod = EngeeComms.DQPSK_ModulatorBaseband() -
dqpskmod = EngeeComms.DQPSK_ModulatorBaseband(Name=Value)creates a system object to perform modulation usage of thedqpskmoddifferential quadrature phase manipulation method with the specifiedNameproperty set to the specifiedValuevalue. You can specify additional arguments as a name-value pair in any order (Name1=Value1,…,NameN=ValueN).Example:
dqpskmod = EngeeComms.DQPSK_ModulatorBaseband(InputType=Bit)
Arguments
Properties
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PhaseRotation —
phase rotation
Float64 real number
Details
The phase difference between the previous and current modulated symbols when the input is zero.
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InputType —
input signal type
String
Details
Indicates whether the input signal consists of integers or bit pairs.
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ConstellationOrdering —
order of signal constellations
String
Details
Determines how the system object maps each pair of input bits to the corresponding integer, using either the Binary or Gray scheme.