RCF VHF Diversity wireless michrophone system RX1000 - Manuale (Pagina 21)

ENGLISH
21
AFP – Anti-feedback processor (RX 1001-AFP ONLY)
Receivers RCF RX 1001-AFP have a complex electronic section dedicated
to the digital
processing of the signal received via radio. This makes it possible not only
to suppress the acoustic feedback (usually a “whistling” noise), but also
introduces a very useful function of frequency response equalisation.
The extreme speed and precision of identifying and eliminating the
frequencies that trigger
feedbacks, the high audio quality (thanks to the 20 bit AD/DA converters)
and the easy use allow radiomicrophones to work properly also in the worst
amplification conditions such as in acoustically critical environments.
The feedback problem, which normally occurs when a microphone is too
close to loudspeakers or when the amplification levels are very high, has
always afflicted audio systems. The AFP system quickly recognises the
rising feedback frequencies and eliminates them by using up to 15 highly
selective dynamic filters (operating simultaneously). If necessary, the filters
can be continuously shifted by the digital signal
processor (DSP) to different frequencies, in order to follow the changing
conditions for the feedback rising due to the transmitter use in motion. The
filter selectivity and breadth are optimised to get the best compromise
between the feedback suppression and the sound quality, as filters basically
remove only the acoustic energy necessary to eliminate feedbacks.
The user can choose two modes with different sensitivity about
identifying and eliminating feedbacks:
• “Low”, suitable for all normal conditions;
• “High”, useful when working under extreme conditions.
USE - On the front panel of the receiver RX 1001-AFP, there is a yellow LED
that indicates the AFP activation. On the receiver back panel, there are two
switches: one with three positions (AFP) and the other with two positions
(EQUALIZER).
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