The RapidM modems include the narrowband HF data modem waveforms which are in compliance with STANAG 4529. This standard describes the Serial Tone Mode (STM) providing data rates ranging from 75 to 1200 bps coded and 600 to 1800 bps uncoded in a 1240 Hz channel.
The original STANAG 4529 (Edition 1) – “Characteristics of Single Tone Modulators/Demodulators for Maritime HF Radio Links in 1240 Hz Bandwidth” was released in February 1995.
- Non-Autobaud capable waveforms providing data rates ranging from 75 to 1200 bps coded and 600 to 1800 bps uncoded in a 1240 Hz channel. The STM waveforms are recommended for backwards interoperability with NATO Broadcast and Ship-to-Shore (BRASS) systems used by Navies.
- The STANAG 4529 waveform does not have embedded AUTOBAUD fields. Thus, the transmitter and receiver need to be set up to the desired data rate and interleaver at both ends of the link. The setting used in one direction of the link does not need be the same as in the reverse direction.
- A narrower occupied bandwidth, compared to STANAG 4285, is achieved by using a symbol rate of 1200 symbols per second.
- The STANAG 4529 waveform is suitable for shore-to-ship use in 1240 Hz channels.
- The single tone PSK waveforms are important for backwards interoperability with NATO BRASS systems used by Navies.
Single Tone Mode (STM):
The table below summarises the complete STANAG 4529 waveform suite. Included in the table are the modulation, code rate and interleaver settings for each data rate. The STANAG 4285 waveform includes tone excision whereby suppression of up to 4 tones is possible. The inclusion of tone excision improves the waveform resilience and performance in the presence of channel interference.
|Waveform||Data Rate (bps)||Modulation
|Coding Rate||Interleaver Settings||Tone Excision Capability|
|75 C||BPSK||1/8||S, L||YES|
Table 1: STANAG 4529 – STM Waveform Suite
The following table gives performance results for the RM Modems (measured using HF Channel Simulator).
The STANAG 4529 standard does not specify any performance requirements. The requirements and measurement conditions given below are based on MS 110A. Please note that the SNR is measured in 3 kHz to alleviate comparisons.
|STANAG 4203 Filters excluded, Test based on MIL-STD-188-110A requirements SNR units: [dB] in 3 kHz|
|IB||HF Channel Conditions||Design Objective||RM Modem SNR
|Doppler Spread [Hz]||Amplitude Path 2 [dB]||Multi-Path Spread [ms]||BER||SNR
Table 2: Performance: STANAG 4529 (STANAG 4203 filters excluded)
STANAG 4529 Modems
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