Frequency Shift and Phase of Sinusoid

I have a very basic conceptual question that I have been having trouble
getting my head around. When shifting the frequency of a sin wave, how
should the phase be handled? For example, this works for integer shift
amounts:

y(t) = sin(shift*(2*pi*f*t + theta))

But if shift is not an integer (1.2, 1.5, etc.) the phase of the
resulting sin wave seems incorrect.

Anybody know how phase should be multiplied when shifting frequency?
This is likely printed in several basic physics texts, but I haven't
stumbled upon it in the ones I have in front of me.

Thanks!
Bob

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Relevant Pages

  • Re: Frequency Shift and Phase of Sinusoid
    ... When shifting the frequency of a sin wave, ... this works for integer shift ... But if shift is not an integer the phase of the ... Anybody know how phase should be multiplied when shifting frequency? ...
    (comp.dsp)
  • Re: Frequency Shift and Phase of Sinusoid
    ... When shifting the frequency of a sin wave, ... Anybody know how phase should be multiplied when shifting frequency? ... If you're treating it as an angular offset, and want to retain that offset at the new frequency, then you should do: ... If, instead, you're treating it as the result of some kind of constant time offset, then your original expression was correct. ...
    (comp.dsp)