11 May 2015

short log, HFDVL and UK WinDRM modems

08345.0 ---: Unid 0634 USB STANAG-4197 (08May15) (AAI)
13560.0 ---: British Mil/Gov, G 1310 USB winDRM modified, OFDM 51-tone Br 37.5 Sh 46.8 (06May15) (AAI) [1] 

14828.6 ---: Unid 1850 USB HFDVL modem OFDM 73-tone Br 30 Sh 37.5 PSK-4 [2]
(04May15) (AAI)14836.0 ---: Russian Mil 1135 USB CIS-12/AT-3004D MPSK-12 Br 120 PSK-2 (08May15) (AAI)
18713.0 ---: Russian Diplo 1220 USB Serdolik MFSK-34 Br 40, Sh 40 (08May15) (AAI)


Two interesting waveforms here: 

[1] UK Mil/Gov modified WinDRM
[2] HFDVL modem OFDM 73-tone Br 30 Sh 37.5 PSK-4


2 comments:

  1. in HFDVL,I guess modulation is PSK4.

    If tone is used for scatterd pilot (every 3 symbols) constelations seems to be psk8.

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  2. found some doc with the following specification for HFDVL modem:

    Total carriers 73
    Pilot carriers 13
    Data symbols per OFDM symbol 41
    Sample rate (sps) 9600
    FFT length 256
    Modulation QPSK
    Bit rate (bps) 2460
    Bandwidth (Hz) 2737.5
    Samples per OFDM symbol 320

    Specification confirms our OFDM analysis about samples and tones. Moreover, yes you are right: QPSK modulation is ok and there are 13 (scatered?) pilot tones.
    Browse the FTP link printed at the bottom in the page http://www.hfdvl.eu then papers/ETT_Wiley_Dic06.pdf

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