Final answer:
To eliminate over modulation, control the amplitude of the input signal for AM transmissions, use limiting amplifiers for FM, and employ automatic gain control or feedback mechanisms to dynamically adjust the modulation parameters within regulatory limits.
Step-by-step explanation:
To eliminate the over modulation phenomena in signal transmission, it's important to ensure that the modulation index stays within acceptable limits. Over modulation occurs when the modulating signal's amplitude is too large compared to the carrier wave, which leads to distortion in the transmitted signal. In amplitude modulation (AM), this can be avoided by carefully controlling the input signal's amplitude and by employing automatic gain control (AGC) circuits that adjust the carrier's amplitude in response to changes in the modulating signal. For frequency modulation (FM), maintaining proper frequency deviation limits and using limiting amplifiers can help mitigate the risk of over modulation. Implementing feedback mechanisms to dynamically adjust modulation parameters can also be effective. Always adhere to the bandwidth limitations set by regulatory bodies to minimize the chance of over modulation.