Which of the following describes signal processing?

Signal processing encompasses a range of operations that manipulate signals to improve their quality or make them suitable for specific applications. The correct choice indicating that "all of the above" describes signal processing is accurate because it encompasses various methods.

Completely reformatting a signal refers to altering the signal in a substantial way, which can include changing its structure or representation to meet specific requirements for different systems or applications.

Amplifying or peaking a signal involves adjusting the signal level to ensure it meets the necessary amplitude for optimal performance, which is crucial in audio and video systems to maintain clarity and prevent loss of information.

Converting signals from one format to another addresses the need to translate between different types of signals, such as analog to digital or vice versa, ensuring compatibility and effective communication in diverse technologies.

Together, these elements highlight the multifaceted nature of signal processing, confirming that the integration of all these processes is essential for achieving the desired signal characteristics in various applications, thus validating "all of the above" as the comprehensive answer.