DQPSK Modulator Baseband
Differential quadrature phase modulation.
Description
Unit DQPSK Modulator Baseband performs modulation with usage of the differential quadrature phase shift keying method. The output signal is a modulated signal in the main frequency band. The input signal must be sampled in time.
Signals with integer value
If the Input type parameters are set to Integer, the allowed input values are 0, 1, 2 and 3. In this case, the block 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 a binary value
If the Input type parameters are set to Bit, the input contains binary value pairs. In this case, the block accepts a column vector whose length is an even integer.
This quadrature vector diagram shows the complex numbers by which the block multiplies the previous character to calculate the current character, depending on whether the Constellation ordering parameters are set to Binary or Gray.
In the following DQPSK signal state transitions diagram, the Phase rotation parameters are set to .
More generally, if the Phase rotation parameters are set to for some integer k, then the signal constellation has 2k points.
Parameters
Input type - type of input signal
Integer(by default) | Bit
Indicates whether the input signal consists of integers or bit pairs.
Constellation ordering - the ordering of the signal constellations
Gray (By default) | `Binary `
Determines how the block maps each pair of input bits to the corresponding integer, using either the Binary or Gray scheme.
Phase rotation (rad) - phase rotation
The phase difference between the previous and current modulated symbols when the input is zero.
Output Data type - output data type
double (by default) | single.
Output Data Type. By default it is set to double.
| Port | Supported data types |
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Input |
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Output |
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