This is the proprietary HFHigh Frequency (3-30 MHz) Data Signal Protocol for the Rohde & Schwarz HFHigh Frequency (3-30 MHz) Modem GM2100. The modem itself supports three data modes, this special R&H data format, STANAG 4285, and MIL-STD-188-110.
This R&S signal format is compatible with those of data modems GM857C4 and GM2000. For GM2100 it was optimized to give data rates between 900 and 5400 bit/sBits per second (bps).
It uses 2PSKBinary Phase-Shift Keying (1 bit per symbol), 4PSKQuadrature Phase-Shift Keying (2 bits per symbol), and 8PSK8-Phase Phase-Shift Keying (3 bits per symbol) modulation. Each frame is 320 symbols, and ACFAutoCorrelation Function is 133.33 msmilliseconds (.001 of a second). Every frame is made up of 5 data subframes of 64 symbols (26.66 msmilliseconds (.001 of a second)).