Signal Guide

Service Description Selection DRM

Here you will find information about the selected service, along with measurement examples.

DRM Theory & Details
Broadcast
Typical Frequency Range:

LW, MW, SW, VHF

General:

DRM (digital radio mondiale) was developed by a consortium of radio broadcasters and manufacturers in order to utilize the frequency ranges previously used by AM transmitters (DRM30 with the four transmission modes A through D). A further variant includes the former FM range (mode E). Audio, video and / or data signals are transmitted. DRM is standardized by ETSI.

Modulation: OFDM, QAM, QPSK

COFDM (coded orthogonal frequency division mutiplex) with various bandwidths. COFDM systems use OFDM modulation with forward error correction. Individual carriers are usually QAM (quadrature amplitude modulation) or QPSK modulated (quadrature phase shift keying). The guard intervals do not show a drop in the carrier.

DRM Measurement Examples
Spectrum
Shows a DRM channel at 5.94 MHz, 10 kHz wide. The steep edges of the COFDM modulation are typical. In contrast, a typical AM channel with carrier and sidebands is seen at 5.98 MHz. The dual use by AM and DRM at 5.95 MHz is interesting. The Avg display offers advantages here due to averaging.
Spectrogram
Overview measurement which also captures an adjacent channel marginally. The channel at 5.94 MHz is occupied only by DRM; the channel starting from 5.95 MHz is used by DRM and AM (cf. Spectrum).
HiRes Spectrogram Full
Overview measurement in only the payload channel here. The spectrum shows mostly even distribution.
HiRes Spectrogram Zoom
Section from HiRes Spectrogram Full gives no further information.
Persistence Spectrum
Light density display from the same data as HiRes Spectrogram Full. Can reveal irregularities in evenly distributed digital signals. Interestingly, other displays do not show the continuous carrier at 5.943 MHz.
Magnitude
Scope
Shows no information because DRM is broadcast as a continuous signal.