User's Manual

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How the Digital Wireless System Works
Signal waveforms are used to represent sound, and the state of the sound is expressed according to the
width or height of the waveform. Wireless microphones transduce the waveform of audio entering the
microphone into an electrical signal and transmit that signal to a tuner over radio waves. In this event, it is
an analog wireless system that processes the audio signal as it is in the waveform. On the other hand, it is a
digital wireless system that digitally processes the audio signal.
More specifically, in the digital system, after an analog signal (waveform) is transduced into a digital signal (a
signal simplified by binary numbers 0 and 1) and transmitted by radio, the digital signal is demodulated
into an analog signal and then the audio is output. By digitally processing and simplifying the audio
information to be transmitted, the system can have a variety of advantages, including strong immunity to
noise and maintenance of clear sound.
Let’s have a look at the “D/U ratio” of analog-to-digital wireless systems. The D/U ratio refers to the ratio of the
desired (D) signal to the undesired (U) signal (unit: dB). The desired signal represents the level of that signal,
while the undesired signal represents the level of signal interference, otherwise called noise. The D/U ratio
decreases as the undesired signal increases. The D/U ratio can be considered to be a value necessary to
maintaining clear sound in a wireless system.
If a comparison is made of the necessary D/U
ratio between analog and digital wireless systems,
it is 40dB for analog systems and 20dB for digital
systems. From this, it can be seen that the digital
wireless system has an edge over the analog
wireless system by 20dB in terms of necessary
D/U ratio, indicating that the digital system can
maintain clear sound in circumstances where a lot
of undesired signals are present.
» How the Digital Wireless System Works
» Why are digital wireless systems resistant to interference signals?
Analog System Digital System
D/U ratio needs
be 40dB or more
for clear sound
reproduction.
D/U ration may be
over 20dB for clear
sound reproduction.
Desired
signal
Undesired
signal
• •
• •
Spectrum Spectrum
Can function correctly
even if more undesired
signals are present as
compared with
analog systems.
Digital signal processing
of analog audio
Demodulation of digital
to audible analog signal
Audio
(analog)
“Hello”
“Hello”
Audio
(analog)
1 2
Wireless microphone Wireless receiver Broadcast
Digital
modulation
Digital
demodulation
1
2
1
2