| 摘要 |
An amplitude limiter for an AM broadcast transmitter to minimize energy in the broadcasted signal outside an allocated broadcast bandwidth. The secondary and higher order spectra (i.e. second and higher harmonics) of a broadcasted AM stereophonic signal are minimized by limiting the amplitude of the audio signal, prior to modulation onto the carrier, within a predetermined portion of the audio frequency range. This is achieved by controlling the gain of the audio signals in that predetermined portion as a function of the level of a submodulation component also within that predetermined portion of the audio frequency range.
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