Sennheiser EM 3731-II Stereo Receiver User Manual


 
Additional information
42
Diversity reception
The receivers operate 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 radio micro-
phones are), the “field strength gap” will then occur with a different trans-
mitter 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 sepa-
rated. 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 (A or B) (see
“Diversity display” on page 10).
Receiver section A Receiver section B