Explanation: Push-pull amplifier circuits are a common and effective choice for RF power stages, including those that might use link coupling for efficient power transfer. The key advantages of a push-pull design are improved efficiency, higher power output, and, most importantly, the cancellation of even-order harmonics. This harmonic cancellation results in a much cleaner output signal, which is critical for preventing interference and meeting spectral purity standards in amateur radio. Conversely, a push-push circuit is primarily used for frequency doubling. A phase splitter is a circuit that creates the two out-of-phase signals required to drive a push-pull amplifier, making it a component of the larger circuit, not the amplifier type itself. An FM discriminator is a circuit found in FM receivers, used to convert an FM signal back into audio, unrelated to RF power amplification.