mil188qammod

MIL-STD-188-110 B/C standard-specific quadrature amplitude modulation (QAM)

Syntax

y = mil188qammod(x,M)

y = mil188qammod(x,M,Name,Value)

Description

y = mil188qammod(x,M) performs QAM modulation on the input signal, x, in accordance with MIL-STD-188-110 and the modulation order, M. For more information, see MIL-STD-188-110.

y = mil188qammod(x,M,Name,Value) specifies options using one or more name-value pair arguments. For example, 'OutputDataType','double' specifies the desired output data type as double. Specify name-value pair arguments after all other input arguments.

Examples

Apply 32-QAM to Data Per MIL-STD-188-110C

Modulate data using 32-QAM as specified in the MIL-188-110C standard. Display the result using a scatter plot.

Set M to 32 and create a data vector containing all possible symbols.

M = 32;
x = (0:M-1);

Modulate the data using QAM as specified in MIL-STD-188-110C.

y = mil188qammod(x,M);

Display the constellation as a scatter plot.

scatterplot(y)

Normalize 16-QAM Modulated MIL-STD-188-110B Signal by Average Power

Modulate data using 16-QAM as specified in the MIL-STD-188-110B standard. Normalize the modulator output so that it has an average signal power of 1 W.

Set M and generate random data.

M = 16;
x = randi([0 M-1],1e5,1);

Modulate the data applying 16-QAM as specified in MIL-STD-188-110B. Using name-value pairs, set the unit average power to true and enable the constellation plot.

y = mil188qammod(x,M,'UnitAveragePower',true,'PlotConstellation',true);

Verify that the signal has approximately unit average power.

avgPow = mean(abs(y).^2)

avgPow = 1.0012

Apply 64-QAM MIL-STD-188-110B Modulation to Bit Data

Modulate a sequence of bits using 64-QAM as specified by MIL-STD188-110B. Display the constellation.

Set the modulation order and generate a sequence of random bits.

M = 64;
numBitsPerSym = log2(M);
data = randi([0 1],1000*numBitsPerSym,1);

Modulate the data applying 64-QAM as specified by MIL-STD-188-110B, and output constellation symbols of single data type.

y = mil188qammod(data,M,'InputType','bit','OutputDataType','single');

Plot the result constellation using a scatter plot.

scatterplot(y)

Input Arguments

x — Input signal

scalar | vector | matrix

Input signal, specified as a scalar, vector, or matrix. The elements of x must be binary values or integers that range from 0 to (M – 1), where M is the modulation order.

Note

To process input signal as binary elements, set the 'InputType' value to 'bit'. For binary inputs, the number of rows must be an integer multiple of log₂(M). Groups of log₂(M) bits in a column are mapped onto a symbol, with the first bit representing the MSB and the last bit representing the LSB.

Data Types: double | single | int8 | int16 | int32 | uint8 | uint16 | uint32 | logical

M — Modulation order

integer

Modulation order, specified as a power of two. The modulation order specifies the total number of points in the signal constellation.

Example: 16

Data Types: double

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: y = mil188qammod(data,M,'InputType','bit','OutputDataType','single');

'InputType' — Input type

'integer' (default) | 'bit'

Input type, specified as the comma-separated pair consisting of 'InputType' and either 'integer' or 'bit'. If you specify 'integer', the input signal must consist of integers from 0 to M – 1. If you specify 'bit', the input signal must contain binary values, and the number of rows must be an integer multiple of log₂(M).

Data Types: char | string

'OutputDataType' — Output data type

'double' (default) | 'single'

Output data type, specified as the comma-separated pair consisting of OutputDataType and 'double' or 'single'.

Data Types: char | string

'UnitAveragePower' — Unit average power flag

false (default) | true

Unit average power flag, specified as the comma-separated pair consisting of 'UnitAveragePower' and a logical scalar. When this flag is true, the function scales the constellation to an average power of 1 watt referenced to 1 ohm. When this flag is false, the function scales the constellation based on specifications in the relevant standard, as described in [1].

Data Types: logical

'PlotConstellation' — Option to plot constellation

false (default) | true

Option to plot constellation, specified as the comma-separated pair consisting of 'PlotConstellation' and a logical scalar. To plot the constellation, set PlotConstellation to true.

Data Types: logical

Output Arguments

y — Modulated signal

scalar | vector | matrix

Modulated signal, returned as a complex scalar, vector, or matrix. The dimension of the output depends on the specified InputType value.

InputType	Dimensions of Output
'integer'	y has the same dimensions as input x.
'bit'	The number of rows in y equals the number of rows in x divided by log2(M).

Data Types: double | single

More About

MIL-STD-188-110

MIL-STD-188-110 is a US Department of Defense standard for HF communications using serial PSK mode of both data and voice signals.

The standard specifies physical layer modulation schemes for tactical and long-haul communications. The modulation scheme specified by the standard is a mix of QAM and APSK. For a detailed description of the modulation scheme, see [1].

References

[1] MIL-STD-188-110B & C: "Interoperability and Performance Standards for Data Modems". Department of Defense Interface Standard, USA.

Extended Capabilities

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