Additional information

Additional information

HiDyn plus™ (HDP) or HDX noise reduction

RF link

Inherent

noise

of the RF link

Transmitter

Receiver

This product family is equipped with the Sennheiser noise reduction systems HDP and HDX. Both compander systems operate on the same principle (described in the following for HDP) but use different parameters (e.g. time constant, type of control). HDP reduces RF interference. It increases the signal-to-noise ratio in wireless audio transmission to more than 110 dB. HDP 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.

HDP has been specially developed for high quality radio microphone systems.

All receivers of the product family feature a AES3 digital audio output for digital mixing consoles. In the receiver the audio signal is digitalized as early as possible so that the noise reduction (compander) can be realized digitally.

Only transmitters and receivers that are equipped with the same compander system can work correctly with each other. If this is not the case, the dynamic range will be drastically reduced and the transmission will sound blunt and flat.

Squelch

Depending on the strength of the received RF signal, the receiver’s audio output is opened or muted. Via the “Squelch” menu, the squelch threshold can be adjusted in 13 steps from 0 to 30 μV.

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