DEVA Broadcast DB7000 Maintenance And Operating Instructions page 40

MPX Positive and MPX Negative - These bar graphs represent the positive and negative
deviation component of the MPX signal. In wideband FM, used in wireless broadcasting, the
instantaneous frequency varies above and below the frequency of the carrier with no modulation.
The carrier frequency shifts in one direction when the instantaneous input wave is with positive
polarity аnd vise-verse - when the instantaneous input wave is with negative polarity, the carrier
frequency shifts in the opposite direction. At every instant in time, the extent of carrier-frequency
shift (the deviation) is directly proportional to the extent to which the signal amplitude is positive
or negative.
Pilot – Represents the deviation caused by Pilot tone injection. Our practice shows that the pilot
deviation should be about 10% of the total deviation of the RF carrier.
RDS – Represents the deviation caused by RDS subcarrier. Our practice shows that the RDS
deviation should be about 5% of the total deviation of the RF carrier.
Group 2. Stereo multiplex related parameters
Mod Input
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FM Output