FLDIGI Users Manual 4.0
Olivia is a family of MFSK modes with a high redundancy Forward Error Correction system similar to MT63. The family is very large, with 40 or more different options, which can make it very difficult to work out which is which. The mode works well on poor HF paths and has good sensitivity. There are three popular modes, which have 8-FSK, 16-FSK and 32-FSK, thus having three, four or five bits per symbol. These three modes can be selected without additional configuration. The tone frequency spacing and integration period should always be left at 8 and 4 respectively unless you are experimenting with another station running an Olivia modem that can be changed. These must always be the same at both ends of the Olivia QSO. The modes have two serious shortcomings - excessive bandwidth combined with slow typing rate, and excessive latency which is the apparent typing delay caused by the integration period.
Each Olivia transmission can start and end with two distinctive tones. These tones are exactly at the lowest and uppermost tones for the selection of tones and bandwidth. They can assist the receiving station in tuning the Olivia signal on the waterfall.
The start/stop tones can be disabled.
See Operating Olivia for additional information.