Tactical HF modem performance: a simplified comparison of serial tone vs. parallel tone approach

A simplified analysis of performance of the PTM (parallel tone modem) and STM (serial tone modem) equipments demonstrates that the PTM will equal or exceed the performance of the STM for short haul tactical HF links. The MilStd 188-110a STM technology demonstrates advances in HF modem technology for channels that exhibit severe multipath conditions. The MilStd 188-110a STM will also enhance performance in disturbed HF channel conditions as occur in the auroral regions. Coding and interleaving are, however, still the most significant factors affecting overall performance in both voice and data communications. In data communications interleaving of up to 5 s with good modern coding techniques will enable acceptable performance with either approach. For voice communications the voice and coding integration applied in the ANDVT works quite effectively and mitigates any advantages of applying MilStd 188-110a STM solutions to this application. This is also unwise given the interoperability achieved under existing military and NATO standards