Error control coding is part of modulation properties for transmitters and demodulation properties for receivers.
STK 10 and later:To apply error control coding, follow these steps in STK:
- Open the properties window for the object. For a Transmitter, go to the Modulator tab on the Basic > Definition page. For a Receiver, go to the Demodulator tab on the Basic > Definition page.
- Using the Name shortcut menu, choose a modulation scheme that includes error control coding. Installed examples include *-BCH-* or Convolutional Coding (BPSK-Conv-*).
You can also create a custom modulation or demodulation file, if you have your own scheme. Information on how to build a external modulation file is in the STK Help documentation at
STK Help > Capabilities > Communications & Radar > External File Formats > External Modulator File. Example files are in C:\Program Files\AGI\STK 12\STKData\Comm\SrcModFiles. A typical file looks like this:
| ModulationName | BPSK-BCH-63-30 |
| BERPoints | |
| 4.4 | 1.0e-2 |
| 5.0 | 3.0e-3 |
| 5.5 | 1.0e-3 |
| 5.95 | 3.0e-4 |
| 6.3 | 1.0e-4 |
| 6.65 | 3.0e-5 |
| 6.9 | 1.0e-5 |
| 7.25 | 3.0e-6 |
| 7.5 | 1.0e-6 |
| 7.75 | 3.0e-7 |
| 7.95 | 1.0e-7 |
The first column is Eb/No and second column is BER. This example uses BCH coding with code rate = 2.1 = 63/30, meaning 30 bits into the encoder and 63 bits out. You can pull data from a table or graph of any user-defined BER curve.
STK 9 and before:The process for choosing an installed modulation scheme is the same as the process described above. The format for external modulation schemes are a little different. Information on how to build a external modulation file is in the STK Help documentation installed locally with your STK 9 or earlier version. Example files are in C:\Program Files\AGI\STK 9.0\STKData\Comm\SrcModFiles. A typical file looks like this:
| BandwidthRatio | 4.2 |
| ModulationType | BPSK |
| CodeType | BCH |
| CodeRate | 2.1 |
| NumberOfPoints | 11 |
| | |
| 4.4 | 1.0e-2 |
| 5.0 | 3.0e-3 |
| 5.5 | 1.0e-3 |
| 5.95 | 3.0e-4 |
| 6.3 | 1.0e-4 |
| 6.65 | 3.0e-5 |
| 6.9 | 1.0e-5 |
| 7.25 | 3.0e-6 |
| 7.5 | 1.0e-6 |
| 7.75 | 3.0e-7 |
| 7.95 | 1.0e-7 |
The first column is Eb/No and the second column is BER. This example uses BCH coding with code rate = 2.1 = 63/30, which means 30 bits into the encoder and 63 bits out. You can pull data from a table or graph of any user defined BER curve.
To learn more about modulation in STK, please see the STK Help System at
STK Help > Capabilities > Communications & Radar > Receivers & Transmitters > Modulators .
