を通じて / を通して|をつうじて / をとおして

1. 1Through or via a medium, means, or intermediary.Ex. 1
2. 2Throughout an entire period or range, without interruption.Ex. 2

Common in news, essays, and explanations to name a channel of information or contact (media, a person, an event), or a whole span of time (一年, 生涯). を通じて sounds slightly more formal than を通して. Unlike にわたって, which stresses how far something extends, the 'throughout' sense stresses continuity across the whole period.

• 1.
  にわたってN2にわたって overlaps with を通じて only in the 'throughout' sense and has no 'via a medium' meaning. It stresses a long duration or wide range, often marks start and end points as 「AからBにわたって」, takes the form にわたる before nouns, and appears mostly in written language.
• 2.
  によって / によるN3The two overlap only in the 'by means of' sense: によって stresses direct means or method and can also mark cause, the agent of a passive, or variation by circumstance, while を通じて stresses going through an intermediary and can also mean 'throughout'. When indicating how information is obtained they are interchangeable, though the emphasis differs.
• 3.
  を経てN1を経て is more formal and refers to moving on to the next step only after going through a period, stage, place, or procedure (「三年を経て」, for example, points to what comes after three years), whereas を通じて expresses 'throughout' or a medium. They are sometimes interchangeable when going through an intermediary person, but を経て is not used to express means.
• 4.
  において / におけるN3において is a written form of で that simply marks the place, time, or field where something happens, whereas を通じて expresses going through a medium or spanning an entire period or range, emphasizing the whole course. Because their meanings differ, they are generally not interchangeable.
• 5.
  にてN2The two overlap only in the 'channel' sense. にて is a formal form of で that also marks location and, as in 「これにて」, signals an ending, while を通じて focuses on going through an intermediary and can also mean 'throughout', a use にて lacks.

にわたって stresses the extent of a span, によって marks means, cause, or agent more generally, and を経て means passing through a place or stage on the way to something. において marks the setting where something happens, and にて is a formal marker of place or means, while を通じて / を通して highlights a channel or an uninterrupted whole period.