COFDMTV
 | |
|---|---|
| Mode | SSB,FM,AM |
| Modulation | COFDM,8-PSK,QPSK |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 1.6 kHz,2.5 kHz,2.7 kHz,3.2 kHz,2.25 kHz,2.4 kHz |
| Location | |
| Short Description | COFDMTV is an easy-to-use picture transmission mode based on Coded Orthogonal Frequency-Division Multiplexing (COFDM). |
| I/Q Raw Recording | — |
| Audio Sample | |
The modes below use a 2/3-rate shortened systematic polar code and are differentially modulated:
using SPC(64800, 43072):
mode 6: 8PSK8-Phase Phase-Shift Keying (3 bits per symbol), 2700 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 10 seconds long
mode 7: 8PSK8-Phase Phase-Shift Keying (3 bits per symbol), 2500 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 11 seconds long
mode 8: QPSKQuadrature Phase-Shift Keying (2 bits per symbol), 2500 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 16 seconds long
mode 9: QPSKQuadrature Phase-Shift Keying (2 bits per symbol), 2250 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 18 seconds long
using SPC(64512, 43072):
mode 10: 8PSK8-Phase Phase-Shift Keying (3 bits per symbol), 3200 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 9 seconds long
mode 11: 8PSK8-Phase Phase-Shift Keying (3 bits per symbol), 2400 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 11 seconds long
mode 12: QPSKQuadrature Phase-Shift Keying (2 bits per symbol), 2400 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 16 seconds long
mode 13: QPSKQuadrature Phase-Shift Keying (2 bits per symbol), 1600 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). BW and about 24 seconds long
The modes allow for a payload of up to 5380 bytes. COFDMTV is based on COFDMCoded Orthogonal Frequency-Division Multiplexing (coded orthogonal frequency-division multiplexing) technology:
- 160 msmilliseconds (.001 of a second) long OFDMOrthogonal Frequency-Division Multiplexing symbols
- 6.25 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). per sub-carrier
- 1⁄8 guard interval
- Differentially encoded PSKPhase-Shift Keying (phase-shift keying) modulation
- Systematic polar codes for forward error correction
Frequencies[edit]
This mode is often used on UHFCB, PMR446, and FRS.
Video Example[edit]
- Receiving COFDMTV encoded picture from a shortwave radio using AM modulation
- Receiving COFDMTV encoded picture from PMR handheld radio
