# Time convention vs time domain, what is the difference?

I really think those are the same thing, but couldn't be so sure.

Is there any difference between time convention and time domain?

For example: "wave propagates along x direction with $$e^{jwt}$$ time convention"

Here, does "time convention" mean time domain?

($$e^{jwt}$$: $$t$$ here means time)

• You will need to give us more context. Neither of these are standard phrases, so the meaning will depend on what context they are being used in. – DJClayworth Apr 7 at 18:45
• @DJClayworth I edited the question based on your comments, thanks – murat Apr 7 at 18:53
• This is about physics, not English. – Michael Harvey Apr 7 at 18:53
• In math and physics, the domain of a function of is the set of all inputs, and it is very common to refer to a function as being in the time domain if it is a function of time (that is, it accepts all time values as inputs). I have never heard of "time convention" in a physics context and it has no meaning to me - where did you get that phrase from? – Canadian Yankee Apr 7 at 19:22
• This isn't a basic language question, it is a technical one. As such, it is more appropriate for a technical SE site (such as Physics) where people with knowledge of these technical terms can be found. – Spencer Apr 7 at 19:25

The terms are not exactly equivalent, although both likely hold in this context.

To work in the time domain is (broadly) to consider a signal's strength as it changes as a function of varying time (as opposed to varying frequency, for example). Parametrizing a signal in terms of e^jwt means working in the time domain because one can plug in the time t (in addition to the signal frequency w and probably a prefactor as well) and obtain the signal amplitude.

The phrase of interest, however, refers to a time convention. This is not a field-specific term but refers simply to the convention used to express the signal as a function of time. Here, the complex exponential form is used, where j is the imaginary number. Another option is the sinusoid form, with the two being related through Euler's identity (see also here). Does this make sense?

No they aren't the same thing. The following explanation is from a DoD technical document. 