Explanation: A synchronizer's main function is to establish precise timing or clocking signals for other circuits, particularly in digital systems or data communications. Pulse or square waves are perfectly suited for this role because their sharp, distinct transitions (rising and falling edges) can reliably define specific points in time. These defined edges are critical for triggering operations, sampling data, or clocking sequential logic with accuracy. Sine waves and triangle waves, being analog and smooth, lack these distinct timing edges, making them less suitable for the precise synchronization of digital processes or for defining discrete clock cycles. Therefore, the output of a synchronizer is typically a digital timing signal, which manifests as a pulse or square wave, essential for coherent and synchronized operation within a system.