Table of Contents
Advertisement
System Behavior in Case of Interference
To understand how analog and digital systems can have a mutual effect on each other in actual operation,
it is important to consider the way in which the demodulated audio signal deteriorates when interference
occurs.
Analog Analog
The stronger the interference, the higher the level of unwanted signals mixed to the audio.
This is heard as so-called beat noise, a chirping or squealing sound.
Digital Analog
As interference gets stronger, a "digital type" hiss noise will gradually be mixed to the audio of the desired
signal.
There is no beat noise typical of analog to analog interference. If the receiver has a function for detecting
noise and muting the output, the audio will eventually be cut off as the interference noise increases.
Analog Digital
Behavior is the same as for digital to digital interference.
As interference gets stronger, errors will cause intermittent audio degradation.
When interference increases further, intermittent muting will occur more frequently.
Finally, the output will be completely muted.
Digital Digital
Behavior is the same as for analog to digital interference.
As interference gets stronger, errors will cause intermittent audio degradation.
When interference increases further, intermittent muting will occur more frequently.
Finally, the output will be completely muted.
With WiDIF-HP, sound quality will not be impaired as long as the D/U signal ratio is 20 dB or more. Unlike with
analog systems, there will also be no loud beat noise in case of interference.
The rapid transition characteristics from high sound quality to muting when interference increases are the
same as for weak field reception. If the same channel must be used in adjacent areas, suitable measures
should be taken to ensure a D/U signal ratio of at least 20 dB. Such measures include maintaining minimum
distances, making appropriate settings for transmission power, and appropriate antenna installation design
and settings. The RF indicator and QL meter functions of the receiver should be used to determine the final
channel plan and equipment settings.
19
WiDIF-HP Precautions
Advertisement
Table of Contents
