Provide dimensioning information for OFDM modulator
infostruct = info(hMod)
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]
hMod — OFDM modulatorOFDM modulator, specified as a comm.OFDMModulator System
object.
infostruct — Dimensions of structure for OFDM modulatorDimensions of structure for OFDM modulator, returned as a structure containing these fields.
DataInputSize — Dimensions of input dataDimensions of input data, returned as a 3-D array of numeric values. The dimensions of this field are Ndata-by-Nsym-by-Nt, where Ndata is the number of data subcarriers such that Ndata = NFFT − NleftG − NrightG − NDCNull − Npilot − NcustNull.
For variable definitions, see Variable Definitions.
PilotInputSize — Dimensions of the pilot input dataDimensions of the pilot input array, returned as a 3-D array of numeric values. The output dimensions of this field are Npilot-by-Nsym-by-Nt.
OutputSize — Dimensions of modulator output dataDimensions of the modulator output data, returned as a 3-D array of numeric values. The dimensions of this field are ((NFFT + NCP)×Nsym)-by-Nt.
For variable definitions, see Variable Definitions.
Data Types: struct
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. |
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