29 May 2015

CIS-60 HDR modem 35.5 Bd, π/8-DPSK8

CIS-60 is one of the Russian OFDM HDR (High Data Rate) Modem modes,  it uses 60 data carriers and 1 pilot carrier located 3300 Hz from dial frequency, as usual in CIS HDR modem series. According to my logs, CIS-60 comes in two waveforms (I have logged both the twos):
- Baudrate 30, modulation QPSK
- Baudrate 35.5, modulation π/8-DPSK8
in both the cases the carriers are 44.5 Hz spaced and the signals spreads a 2800 Hz bandwidth. Sometimes you could hear operators chatting (in voice) followed by a waveform switch, i.e. from DPSK-4 to DPSK-8: I do not know if it's for tests purposes or for some other reason. The original signal has been resampled to 8888.8 Hz.

radioscanner.ru reports CIS-60 DPSK-8 waveform here:

No comments:

Post a Comment