Which technique transmits a coded, long duration, high energy pulse?

The correct answer is Pulse Compression. This technique is used to enhance the resolution and range of radar systems. Pulse compression allows for the transmission of a long-duration pulse, which is then compressed upon reception, resulting in a more precise localization of targets. By utilizing coded waveforms, the system can transmit energy over an extended period while still achieving the desired resolution and range, effectively improving the radar's performance.

Pulse compression employs modulation techniques like frequency or phase modulation to encode information within the long pulse, which ensures that high energy is maintained during transmission. This makes it possible to detect even distant or small objects more reliably compared to standard pulse transmission techniques that do not utilize compression.

In contrast, the other techniques listed do not fit the description of transmitting a long-duration, high-energy pulse. Each serves different purposes in electronic warfare and radar application contexts, but none focus specifically on the characteristics outlined in the question regarding long-duration and high energy all at once.