Sennheiser EM 500 G2 Notice D'emploi page 60

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Squelch
Pilot tone squelch
The ew 500 G2 transmitters adds a pilot tone to the audio signal. The receiver
checks incoming audio signals to see if the pilot tone is present. In the
absence of the pilot tone, the receiver's audio output will remain muted, even
if a strong RF signal is present.
This prevents strong interfering signals from causing hissing noise in the
receiver when the transmitters are switched off.
In order to benefit from this feature, the pilot tone function must be activated
on both the transmitter and the receiver. The receiver's pilot tone function is
factory-preset to "ON" (= activated).
Field strength-dependent squelch
Depending on the strength of the received RF signal, the receiver's audio
output is opened or muted. Via the "Squelch" menu of the receiver, the
squelch threshold can be adjusted in three steps (Low, Mid, High).
Diversity reception
The receiver operates on the "true diversity" principle:
A receiving antenna receives not only the electromagnetic waves which reach
it by a direct path, but also the reflections of these waves which are created
in the room by walls, windows, ceilings and fittings. When these waves are
superimposed, destructive interference occurs, which can also be called "field
strength gaps". Repositioning the receiving antenna can bring a solution.
With mobile transmitters, however (which all radiomicrophones are), the
"field strength gap" will then occur with a different transmitter position.
These "field strength gaps" can only be eliminated with true diversity
receivers.
In true diversity, instead of one antenna and one receiver there are now two
antennas and two receiver sections. The antennas are spatially separated. By
means of a comparison circuit, the receiver section with the strongest RF
signal is always switched to the common AF output. The risk of the
occurrence of "field strength gaps" in both antennas at the same time is
virtually nonexistant.
The receiver display panel shows the active diversity section (I or II) .
Electronic
Control signal Control signal
switch-over of
Receiver section I AF signal Receiver section II
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