KYOWA MRS-100 Series, Инструкция по эксплуатации

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7-2. Reception system using two receiving antennas (diversity reception techniques)
Reception techniques called “diversity reception methods” are used to increase the reliability of radio
communication. For example, multiple receiving antennas may be used to prioritize signals from antennas with
better receptions. Alternatively, radio signals from multiple receiving antennas may be combined.
A few types of diversity reception methods are used.
• Space diversity technique
A reception technique in which the receiver’s two receiving antennas are positioned at least a half-wave
length apart (approximately 63 mm for 2.4 GHz radio waves) to receive radio waves at the receiving
antennas that have no correlation to each other. For this reason, when radio waves are received in
environments with a weak signal, even if conditions are poor at one receiving antenna, the other antenna
can still be relied on to have reception.
• Polarization diversity technique
Radio waves sent from the transmitter may reach the receiver in a plane of polarization different from that
of the transmitter’s transmitted polarization, due to reflection on metal walls and/or other obstacles.
Alternatively, if the transmitter rotates because it is on a rotating object, the polarization as received by the
receiver also rotates.
In such case, preparing a receiving antenna with a different plane of polarization enables the receiver to give
precedence to the receiving antenna in a better receiving condition.
[Example of installation with the space diversity technique]
The receiver’s receiving antennas are well spaced
apart, enabling reception of transmitted radio waves
that have no correlation with each other.
Waves without wireless communication errors are
chosen to be used.
(Even if obstacles are blocking the reception for one
antenna, the other antenna can complement its
performance.)
Wall, groundplane, metal surface
Transmitting
wave
Transmitted radio waves
with rotated polarization,
due to reflection
Transmitter
Receiver