EngeeComms.DQPSK_DemodulatorBaseband

Demodulates data modulated using the DQPSK method.

Library	`EngeeComms`.
Block	DQPSK Demodulator Baseband

Description

The system object EngeeComms.DQPSK_DemodulatorBaseband demodulates a signal that has been modulated using the differential quadrature phase shift keying (DQPSK) method. The input is a basic representation of the modulated signal.

The input signal must be a discrete complex signal. The output depends on the phase difference between the current and previous symbol. The first integer (or binary pair if the property OutputType is set to Bit) at the output of the system object is the initial state of zero, since there is no previous symbol.

To demodulate a signal that has been modulated using the differential quadrature phase manipulation method, perform the following steps:

Create an object EngeeComms.DQPSK_DemodulatorBaseband and set its properties.
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.

Output data types and constellations

If the property OutputType is set to Integer, the system object displays the phase difference between and , where is the value of the property PhaseRotation and takes the value 0, 1, 2 or 3.

If the property * OutputType property is set to Bit, the output is pairs of binary values.

Syntax

Creation

dqpskdemod = EngeeComms.DQPSK_DemodulatorBaseband() creates a dqpskdemod system object to perform demodulation of a signal that has been modulated using the differential quadrature phase shift keying method, with by default properties.

Example:
```
dqpskdemod = EngeeComms.DQPSK_DemodulatorBaseband()
```
dqpskdemod = EngeeComms.DQPSK_DemodulatorBaseband(Name=Value) creates a dqpskdemod system object to perform demodulation of a signal that has been modulated using the differential quadrature phase manipulation method, with the specified Name property set to the specified Value value. You can specify additional arguments as a name-value pair in any order (Name1=Value1,…,NameN=ValueN).

Example:
```
dqpskdemod = EngeeComms.DQPSK_DemodulatorBaseband(OutputType=Bit)
```

Usage

outsignal = dqpskdemod(insignal) performs demodulation of a signal that has been modulated using the differential quadrature phase manipulation method as specified in dqpskdemod. The result is returned in outsignal.

Arguments

Input arguments

In - input DQPSK modulated signal
scalar | vector

Details

The input DQPSK-modulated signal as a scalar or vector.

Data types

Float64

Output arguments

Out - demodulated signal
vector | scalar

Details

Demodulated signal in the form of a scalar or vector.

Data types

Float16, Float32, Float64, Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Bool

Properties

# PhaseRotation — phase rotation
Float64 real number

Details

The phase difference between the previous and current modulated symbols when the input is zero.

# OutputType — output signal type
String

Details

Indicates whether the output signal consists of integers or bit pairs.

# ConstellationOrdering — constellation ordering
String

Details

Determines how the system object maps each pair of input bits to the corresponding integer, using either the Binary or Gray scheme.

Methods

Common for all system objects

`step!`	Start the system object’s operating algorithm
`reset!`	Reset the internal states of the system object