SSTV.org.ukDRM specification · DRM+
Time- and frequency-selective VHF channels.
VHF DRM+ operation on a 100 kHz raster with the same DRM multiplex/signalling model and a much shorter frame.
| Parameter | Value |
|---|---|
| Useful symbol duration Tu | 2.25 ms |
| Guard duration Tg | 0.25 ms |
| Total symbol duration Ts | 2.5 ms |
| Guard ratio Tg/Tu | 1/9 |
| Carrier spacing | 444.44 Hz |
| Transmission frame | 40 symbols / 100 ms |
| Nominal channel widths | 100 kHz |
Higher bandwidth and shorter OFDM timing suit VHF broadcast planning, not narrow HF SSB digital SSTV audio channels.
| Occupancy | Bandwidth | Kmin | Kmax | Unused indices | Occupied positions |
|---|---|---|---|---|---|
| 0 | 100 kHz | -106 | 106 | none | 213 |
Select DRM Mode E and provide 192 kHz complex I/Q. In the downloadable WAV, channel one is I and channel two is Q. The 100 kHz channel cannot be recovered from ordinary voice-band microphone audio.
Synchronization identifies the waveform. FAC describes the multiplex; SDC describes services and stream allocation; MSC carries the application data. The image in this sample is an MOT object. FAC lock alone does not prove image recovery, and an audio-only broadcast may provide no image to display.
The digital test-card JPEG carried in a DRM MOT image service.
192,000 samples/s · 2 channels · 24.00 s
Complex I/Q data. Import as I/Q with the listed sample rate and I,Q channel order; speaker playback is not a decode preview.
Generated by the SSTV 2.0 pinned transmitter library; PCM16 WAV verified by its writer.
The sample uses 4-QAM MSC, 4-QAM SDC and long interleaving in the native Mode E profile. The payload is a JPEG test card, not a recording of a broadcast station.