Digital Radio Mondiale (DRM)

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Digital Radio Mondiale (DRM)
DRMimage.png
Frequencies 909 kHzKiloHertz (kHz) 10^3 Hz909,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
0.909 MHzMegaHertz (MHz) 10^6 Hz
,26060 kHzKiloHertz (kHz) 10^3 Hz26,060,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
26.06 MHzMegaHertz (MHz) 10^6 Hz
909 kHzKiloHertz (kHz) 10^3 Hz
0.909 MHzMegaHertz (MHz) 10^6 Hz
26,060 kHzKiloHertz (kHz) 10^3 Hz
26.06 MHzMegaHertz (MHz) 10^6 Hz
Frequency Range 909 kHzKiloHertz (kHz) 10^3 Hz909,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
0.909 MHzMegaHertz (MHz) 10^6 Hz
- 26.06 MHzMegaHertz (MHz) 10^6 Hz26,060,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
26,060 kHzKiloHertz (kHz) 10^3 Hz
Mode USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
Modulation QAMQuadrature Amplitude Modulation,OFDMOrthogonal Frequency-Division Multiplexing
ACFAutoCorrelation Function 400 msmilliseconds (.001 of a second)
Bandwidth 4500 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).4.5 kHzKiloHertz (kHz) 10^3 Hz
0.0045 MHzMegaHertz (MHz) 10^6 Hz
,5000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).kHzKiloHertz (kHz) 10^3 Hz
0.005 MHzMegaHertz (MHz) 10^6 Hz
,9000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).kHzKiloHertz (kHz) 10^3 Hz
0.009 MHzMegaHertz (MHz) 10^6 Hz
,10000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).10 kHzKiloHertz (kHz) 10^3 Hz
0.01 MHzMegaHertz (MHz) 10^6 Hz
,18000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).18 kHzKiloHertz (kHz) 10^3 Hz
0.018 MHzMegaHertz (MHz) 10^6 Hz
,20000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).20 kHzKiloHertz (kHz) 10^3 Hz
0.02 MHzMegaHertz (MHz) 10^6 Hz
4.5 kHzKiloHertz (kHz) 10^3 Hz
0.0045 MHzMegaHertz (MHz) 10^6 Hz
20 kHzKiloHertz (kHz) 10^3 Hz
0.02 MHzMegaHertz (MHz) 10^6 Hz
Location Worldwide
Short Description Digital Radio Mondiale (DRM) is a digital commercial broadcasting mode used to deliver FMFrequency Modulation-comparable sound quality to shortwave radio.
I/Q Raw Recording
Audio Sample
Digital Radio Mondiale (DRM) is a digital commercial broadcasting mode used to deliver FMFrequency Modulation-comparable sound quality to shortwave radio. DRM is a digital alternative to AMAmplitude Modulation shortwave radio. WinDRM is an amateur adoption of this mode.

DRM uses COFDMCoded Orthogonal Frequency-Division Multiplexing (Coded Orthogonal Frequency Division Multiplexing) with QAMQuadrature Amplitude Modulation (Quadrature Amplitude Modulation).

DRM is commonly seen with 10 kHzKiloHertz (kHz) 10^3 Hz of bandwidth. Other bandwidths are used rarely.


Bandwidths[edit]

DRM is commonly seen with 10 kHzKiloHertz (kHz) 10^3 Hz of bandwidth. Other bandwidths are used rarely.

  • 4.5 kHzKiloHertz (kHz) 10^3 Hz. Gives the ability for the broadcaster to do a simulcast and use the lower-sideband area of a 9 kHzKiloHertz (kHz) 10^3 Hz raster channel for AMAmplitude Modulation, with a 4.5 kHzKiloHertz (kHz) 10^3 Hz DRM signal occupying the area traditionally taken by the upper-sideband.[12] However the resulting bit rate and audio quality is not good.
  • 5 kHzKiloHertz (kHz) 10^3 Hz. Gives the ability for the broadcaster to do a simulcast and use the lower-sideband area of a 10 kHzKiloHertz (kHz) 10^3 Hz raster channel for AMAmplitude Modulation, with a 5 kHzKiloHertz (kHz) 10^3 Hz DRM signal occupying the area traditionally taken by the upper-sideband. However the resulting bitrate and audio quality is marginal (7.1–16.7 kbit/sKilobits per second (kbps) for 5 kHzKiloHertz (kHz) 10^3 Hz). This technique could be used on the short wave bands throughout the world.
  • 9 kHzKiloHertz (kHz) 10^3 Hz. Occupies half the standard bandwidth of a region–1 long wave or medium wave broadcast channel.
  • 10 kHzKiloHertz (kHz) 10^3 Hz. Occupies half the standard bandwidth of a region–2 broadcast channel. could be used to simulcast with analogue audio channel restricted to NRSC5. Occupies a full worldwide shortwave broadcast channel (giving 14.8–34.8 kbit/sKilobits per second (kbps))
  • 18 kHzKiloHertz (kHz) 10^3 Hz. Occupies full bandwidth of region–1 long wave or medium wave channels according to the existing frequency plan. This offers better audio quality.
  • 20 kHzKiloHertz (kHz) 10^3 Hz. Occupies full bandwidth of region–2 or 3 AMAmplitude Modulation channel according to the existing frequency plan. This offers highest audio quality of the DRM30 standard (giving 30.6–72 kbit/sKilobits per second (kbps)).

Modes[edit]

DRM has 4 main modes, from A to D. Different modes are used to accommodate varying propagation conditions.

  • A: Gaussian channel with very little multipath propagation and Doppler effect. This profile is suited for local or regional broadcasting.
  • B: multipath propagation channel. This mode is suited for medium range transmission. It is nowadays frequently used.
  • C: similar to mode B, but with better robustness to Doppler (more carrier spacing). This mode is suited for long distance transmission.
  • D: similar to mode B, but with a resistance to large delay spread and Doppler spread. This case exists with adverse propagation conditions on very long distance transmissions. The useful bit rate for this profile is decreased.
Mode OFDMOrthogonal Frequency-Division Multiplexing carrier spacing (HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).) Number of carriers Symbol length (msmilliseconds (.001 of a second)) Guard interval length (msmilliseconds (.001 of a second)) Nb symbols per frame
kHzKiloHertz (kHz) 10^3 Hz 10 kHzKiloHertz (kHz) 10^3 Hz 18 kHzKiloHertz (kHz) 10^3 Hz 20 kHzKiloHertz (kHz) 10^3 Hz
A 41.66 204 228 412 460 26.66 2.66 15
B 46.88 182 206 366 410 26.66 5.33 15
C 68.18 - 138 - 280 20.00 5.33 20
D 107.14 - 88 - 178 16.66 7.33 24

Frequencies[edit]

Most DRM broadcasts are found in the shortwave band usually between 1 MHzMegaHertz (MHz) 10^6 Hz to 26 MHzMegaHertz (MHz) 10^6 Hz. A list of DRM broadcasts and times can be found at this Schedule of DRM broadcasts. The only VHFVery High Frequency (30-300 MHz)-based DRM as of 2015 is a 98900 kHzKiloHertz (kHz) 10^3 Hz Slovakian broadcast.

Decoding Software[edit]

Hobby Level Software

Decoding Tutorials[edit]

Video Examples[edit]

Additional Links[edit]

Additional Images[edit]