Signal Guide

Service Description Selection DAB

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

DAB Theory & Details
Broadcast
Typical Frequency Range:

174 – 230 MHz (VHF-Band)
1452 – 1467.5 MHz (L-Band)

General:

DAB, digital audio broadcasting or digital radio, is a digital broadcasting system for sound broadcasting in the VHF and L bands. Common frequency networks are possible. DAB is standardized by ETSI as EN 300 401.

Modulation: COFDM, QPSK

COFDM (coded orthogonal frequency division multiplex). COFDM systems use OFDM modulation with forward error correction. Individual carriers are QPSK modulated (quadrature phase shift keying). The guard intervals do not show any carrier drop.

DAB Measurement Examples
Spectrum
Shows a DAB channel, normally evenly distributed but here strongly affected by reflections (breakthrough at 200.6 MHz). These effects are compensated for by error correction.
Spectrogram
The line spectrum gives information about the guard intervals.
HiRes Spectrogram Full
Overview measurement over 125 ms. Shows two guard intervals and otherwise even occupancy. The breakthrough at 200.6 MHz caused by reflections is clearly seen.
HiRes Spectrogram Zoom
Section from the same data as HiRes Spectrogram Full. Spectrogram Full with enlarged display of the guard gap. The lowered carriers can be seen. Underlying in-band interference would be easy to spot here.
Persistence Spectrum
Light density display from the same data as HiRes Spectrogram Full. Can reveal irregularities in evenly distributed digital signals.
Magnitude
Obtained from the same data as HiRes Spectrogram Full. The DAB transmission shows two guard intervals separated by 96 ms.
Scope
The DAB transmission shows two guard intervals separated by 96 ms. The variety of displays possible in Scope is much more flexible than in Magnitude.