Which signal parameters can be viewed in the frequency domain?

The correct answer highlights key parameters that can be effectively analyzed when examining a signal in the frequency domain. Channel amplitude refers to the magnitude of signals at different frequencies, providing insight into how signals behave over a range of frequencies. Bandwidth indicates the range of frequencies a signal occupies, which is crucial for understanding how much information can be transmitted and how susceptible the signal may be to impairments. Nearby impairments addressed in this context include any disturbances or interference affecting the signal quality, which can significantly alter performance as seen in the frequency spectrum.

In contrast, the other options encompass parameters that are more associated with time-domain analysis or aspects that do not directly relate to viewing signals in the frequency domain. Voltage level and phase shift, while important, are typically analyzed in the context of signal integrity rather than purely in frequency terms. Bit error rate and latency are metrics that focus primarily on the performance and delay of data transmission rather than the signal's frequency characteristics. Lastly, modulation type, channel length, and sample rate, while relevant to the broader context of signal transmission, do not specifically represent characteristics that are typically visualized when examining signals in the frequency domain.