PAM, or pulse amplitude modulation, is considered ineffective for long-distance transmission primarily due to its susceptibility to noise and distortion, which can degrade signal quality over extended distances. The infinite length of the output signal can complicate synchronization and increase the likelihood of errors in data interpretation. Additionally, PAM does not utilize bandwidth efficiently compared to other modulation techniques, leading to potential limitations in data rate and reliability. Understanding PAM's limitations is crucial for applications in digital communication and transmission line theory. Overall, PAM's drawbacks make it less suitable for long-distance communication scenarios.
