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DVBS-APSK Demodulator Baseband

DVB--S2/S2X/SH standard-specific amplitude phase shift keying (APSK) demodulation

  • Library:
  • Communications Toolbox / Modulation / Digital Baseband Modulation / APM

    Communications Toolbox / Modulation / Digital Baseband Modulation / Standard-Compliant

Description

The DVBS-APSK Demodulator Baseband block demodulates the input signal using Digital Video Broadcasting (DVB-S2/S2X/SH) standard-specific amplitude phase shift keying (APSK) demodulation. For a description of DVB-compliant APSK demodulation, see DVB Compliant APSK Hard Demodulation and DVB Compliant APSK Soft Demodulation.

This icon shows the block with all ports enabled:

Ports

Input

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DVB-S2/S2X/SH standard-specific APSK modulated signal, specified as a scalar, vector, or matrix. When this input is a matrix, each column is treated as an independent channel. This port is unnamed until the Var port is enabled.

Data Types: double | single
Complex Number Support: Yes

Noise variance, specified as a positive scalar or vector of positive values. When the noise variance or signal power result in computations involving extreme positive or negative magnitudes, see DVB Compliant APSK Soft Demodulation for demodulation decision type considerations.

Dependencies

This parameter applies when Noise variance source is set to Input port.

Data Types: double | single

Output

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Demodulated signal, returned as a scalar, vector, or matrix. The dimensions of the demodulated signal depend on the specified Output type and Decision type. This port is unnamed on the block.

Output type Decision typeDemodulated Signal DescriptionDimensions of Demodulated Signal
IntegerDemodulated integer values in the range [0, (M – 1)]The output signal has the same dimensions as the input signal.
BitHard decisionDemodulated bitsThe number of rows in the output signal is log2(M) times the number of rows in the input signal. Each demodulated symbol is mapped to a group of log2(M) elements in a column, where the first element represents the MSB and the last element represents the LSB.
Log-likelihood ratioLog-likelihood ratio value for each bit
Approximate log-likelihood ratioApproximate log-likelihood ratio value for each bit

M is the value of Modulation order.

Use Output data type to specify the output data type.

Parameters

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Standard suffix for DVB modulation variant, specified as S2, S2X, or SH.

Frame length, specified as Normal or Short.

Dependencies

This parameter applies only when DVB standard suffix is set to S2 or S2X.

Modulation order, specified as a power of two. The modulation order specifies the total number of points in the constellation of the input signal. The list of valid modulation orders varies depending on the setting for DVB standard suffix and Frame length.

DVB standard suffixFrame lengthModulation order Options
S2Normal or Short16 or 32
S2XNormal8, 16, 32, 64, or 256
Short16 or 32
SHNot applicable16

Code identifier, specified as a character vector. The list of valid code identifier values varies depending on the setting for DVB standard suffix, Frame length, and Modulation order. This table lists the available options for Code identifier values.

Modulation orderDVB standard suffixFrame length Code identifier Options
8

S2X

Normal

100/180 or 104/180

16

S2 or S2X

Normal

2/3, 3/4, 4/5, 5/6, 8/9, or 9/10

Short

2/3, 3/4, 4/5, 5/6, or 8/9

16

S2X

Normal

26/45, 3/5, 28/45, 23/36, 25/36, 13/18, 140/180, 154/180, 100/180, 96/180, 90/180, 18/30, or 20/30

Short

7/15, 8/16, 26/45, 3/5, or 32/45

32

S2 or S2X

Normal

3/4, 4/5, 5/6, 8/9, or 9/10

Short

3/4, 4/5, 5/6, or 8/9

32

S2X

Normal

128/180, 132/180, 140/180, or 2/3

Short

2/3 or 32/45

64

S2X

Normal

128/180 , 132/180, 7/9, 4/5, or 5/6

128

S2X

Normal

135/180 or 140/180

256

S2X

Normal

116/180, 124/180, 128/180, 20/30, or 135/180

For more information, refer to Tables 9 and 10 in the DVB-S2 standard [1] and Table 17a in the DVB-S2X standard [2].

Dependencies

This parameter applies only when DVB standard suffix is set to S2 or S2X.

Constellation scaling, specified as Outer radius as 1 or Unit average power.

Dependencies

This input argument applies only when DVB standard suffix is set to S2 or S2X.

Output type, specified as Integer or Bit.

Data Types: char | string

Demodulation decision type, specified as Hard decision, Log-likelihood ratio, or Approximate log-likelihood ratio. See DVB Compliant APSK Soft Demodulation for algorithm selection considerations.

Dependencies

This parameter applies when Output type is set to Bit.

Noise variance source, specified as:

  • Property — The noise variance is set using the Noise variance parameter.

  • Input port — The noise variance is set using the Var input port.

Noise variance, specified as a positive scalar or vector of positive values.

  • When specified as a scalar, that value is used on all elements in the input signal.

  • When specified as a vector, the vector length must be equal to the number of columns in the input signal. Each noise variance vector element is applied to its corresponding column in the input signal.

When the noise variance or signal power result in computations involving extreme positive or negative magnitudes, see DVB Compliant APSK Soft Demodulation for demodulation decision type considerations.

Dependencies

This parameter applies when Noise variance source is set to Property and Decision type is set to either Log-likelihood ratio or Approximate log-likelihood ratio.

Data Types: double

Output data type, specified as one of the acceptable values from this table. Acceptable Output data type values depend on the Output type and Decision type parameter values.

Output typeDecision typeOutput data type Options
IntegerNot applicabledouble, single, int8, uint8, int16, uint16, int32, or uint32
BitHard decisiondouble, single, int8, uint8, int16, uint16, int32, uint32, or logical
Log-likelihood ratio or Approximate log-likelihood ratioThe output signal is the same data type as the input signal.

Dependencies

This parameter applies only when Output type is set to Integer or when Output type is set to Bit and Decision type is set to Hard decision.

Type of simulation to run, specified as:

  • Code generation –– Simulate the model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations as long as the model does not change. This option requires additional startup time.

  • Interpreted execution –– Simulate the model using the MATLAB® interpreter. This option shortens startup time. In Interpreted execution mode, you can debug the source code of the block.

For information on execution speed, see Tips.

Block Characteristics

Data Types

double | single | Boolean | base integer

Multidimensional Signals

Yes

Variable-Size Signals

No

More About

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Tips

  • For faster execution of the DVBS-APSK Demodulator Baseband block, set the Simulate using parameter to:

    • Code generation when using hard decision demodulation.

    • Interpreted execution when using soft decision demodulation.

References

[1] ETSI Standard EN 302 307 V1.4.1: Digital Video Broadcasting (DVB); Second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB-S2), European Telecommunications Standards Institute, Valbonne, France, 2005-03.

[2] ETSI Standard EN 302 307-2 V1.1.1: Digital Video Broadcasting (DVB); Second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB-S2X), European Telecommunications Standards Institute, Valbonne, France, 2015-02.

[3] ETSI Standard EN 302 583 V1.1.1: Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for Satellite Services to Handheld devices (SH), European Telecommunications Standards Institute, Valbonne, France, 2008-03.

[4] Sebesta, J. “Efficient Method for APSK Demodulation.” Selected Topics on Applied Mathematics, Circuits, Systems, and Signals (P. Pardalos, N. Mastorakis, V. Mladenov, and Z. Bojkovic, eds.). Vouliagmeni, Athens, Greece: WSEAS Press, 2009.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Introduced in R2018b