Which one of the following statements is correct?

Emitter-Coupled Logic (ECL):

• It exhibits the least propagation delay among the options due to its unique design.
• ECL is a high-speed digital logic family that relies on differential amplifiers in its circuitry.

Differential amplifier: ECL uses differential amplifies in its gates, which allow for very fast switching times. This is because the differential amplifiers can quickly change their output based on small input changes, resulting in minimal propagation delay.

Parallel Operation: ECL gates operate in parallel, allowing multiple transistors to switch simultaneously. This parallelism contributes to faster overall circuit response.

Here, option 1 is correct.