Sennheiser SR 3256 User Manual

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Additional information
HDX 
noise reduction
Progress you can hear:
The product family is equipped with 
HDX
, the Sennheiser noise
reduction system that reduces RF interference. It increases the
signal-to-noise ratio in wireless audio transmission to more
than 90 dB.
HDX
 is a wideband compander system which compresses the
audio signal in the transmitter in a 2:1 ratio (related to dB) to
lift it above the inherent noise floor of the RF link. In the receiver
the signal is expanded in an identical and opposite way in a 1:2
ratio to restore the original signal, at the same time reducing
the RF noise to below the noise floor of the receiver.
HDX
 has been specially developed for high quality radio
microphone systems.
Note:
Only transmitters and receivers that are equipped with 
HDX
can work correctly with each other. If non HDX equipment
was mixed with 
HDX
, the dynamic range would be
drastically reduced and the transmission would sound blunt
and flat.
RF link
Transmitter
Receiver
Inherent 
noise of 
the RF link