info

Provide dimensioning information for OFDM modulator

Syntax

infostruct = info(hMod)

Description

infostruct = info(hMod) returns the input, pilot, and output data dimensions for the specified OFDM modulator System object™.

Examples

Determine OFDM Modulator Data Dimensions

Get the OFDM modulator data dimensions by using the info object function.

Construct an OFDM modulator System object™ with user-specified pilot indices, an inserted DC null, and specify two transmit antennas.

hMod = comm.OFDMModulator('NumGuardBandCarriers',[4;3], ...
    'PilotInputPort',true, ...
    'PilotCarrierIndices',cat(3,[12; 26; 40; 54], ...
    [11; 25; 39; 53]), ...
    'InsertDCNull',true, ...
    'NumTransmitAntennas',2);

Use the info object function to get the modulator input data, pilot input data, and output data sizes.

info(hMod)

ans = struct with fields:
     DataInputSize: [48 1 2]
    PilotInputSize: [4 1 2]
        OutputSize: [80 2]

Input Arguments

hMod — OFDM modulator

System object

OFDM modulator, specified as a comm.OFDMModulator System object.

Output Arguments

infostruct — Dimensions of structure for OFDM modulator

struct

Dimensions of structure for OFDM modulator, returned as a structure containing these fields.

DataInputSize — Dimensions of input data

3-D array

Dimensions of input data, returned as a 3-D array of numeric values. The dimensions of this field are N_data-by-N_sym-by-N_t, where N_data is the number of data subcarriers such that N_data = N_FFT − N_leftG − N_rightG − N_DCNull − N_pilot − N_custNull.

For variable definitions, see Variable Definitions.

PilotInputSize — Dimensions of the pilot input data

3-D array

Dimensions of the pilot input array, returned as a 3-D array of numeric values. The output dimensions of this field are N_pilot-by-N_sym-by-N_t.

OutputSize — Dimensions of modulator output data

3-D array

Dimensions of the modulator output data, returned as a 3-D array of numeric values. The dimensions of this field are ((N_FFT + N_CP)×N_sym)-by-N_t.

For variable definitions, see Variable Definitions.

Data Types: struct

More About

List of Variables

The variables mentioned in this table are defined in this table:

Variable Definitions

Variable	Description
NFFT	Number of subcarriers
NleftG	Number of subcarriers in the left guard band
NrightG	Number of subcarriers in the right guard band
NDCNull	Number of subcarriers in the DC null (either 0 or 1)
Npilot	Number of pilot subcarriers
NcustNull	Number of subcarriers used for custom nulls (applies only when the PilotCarrierIndices property of input hMod is a 3-D array)
Nt	Number of transmit antennas
NCP	Length of cyclic prefix.