What commonly causes amplitude measurements of digital modulation channels to be lower than expected when using a signal level meter?

The common cause of amplitude measurements of digital modulation channels being lower than expected when using a signal level meter is due to a narrow resolution bandwidth in the equipment. When the resolution bandwidth is too narrow, it can filter out parts of the signal that contribute to the overall amplitude measurement. This is critical when dealing with digital signals, which often have spectral characteristics that can spread across a frequency band.

In digital modulation, the signal may not occupy the entire bandwidth due to its inherent nature or modulation techniques, leading to under-reporting of the signal’s power if the selected bandwidth is not wide enough to capture all relevant frequencies. A proper resolution bandwidth ensures that the meter can accurately measure all aspects of the signal, giving a true representation of the amplitude present.

Other factors, while relevant, do not directly explain why the amplitude measurements would be lower. For instance, inadequate signal conditioning may affect the clarity or quality of the signal but would not inherently lead to lower average amplitude readings. Interference from surrounding channels can cause distortions or show additional signals; however, it does not typically result in amplitude readings that are systematically lower than expected. Digital signals having a higher average power would also not normally relate to amplitude measurements being lower; the relationship is based more on how the signal