# How do you determine the power required for a phase shift keying modulation scheme?

This wiki article has a diagram :

which shows how the message "11000110" is conveyed as a waveform.

I'm trying to understand how the power to transmit this message can be determined.

Do I need to integrate the magnitude of the I(t) and Q(t) signals to determine power? Is there a formula somewhere?

• @DilipSarwate - I'm assuming it depends on a bunch of cases. Where can I find the power formula for each case? – user1068636 Mar 28 '20 at 2:48
• Absent any precise mathematical formulation about the waveform details (just showing waveform shapes is not enough), all that can be said is that you need to integrate integrate the sum of the squared magnitudes of the I and Q waveforms to find the signal power. As to what these integrals work out to be, there are general formulas for specific waveforms but whether any of those formulas are applicable to your particular waveforms is something that that the readership of dsp.SE is quite unable to determine. – Dilip Sarwate Mar 28 '20 at 2:56
• @DilipSarwate - Assuming $I(t)$ and $Q(t)$ are known, are you suggesting the power formula would be: $$\int_0^{4T_s}I^2(t)dt + \int_0^{4T_s}Q^2(t)dt$$ ? – user1068636 Mar 28 '20 at 3:03
• Well, the formula you wrote will give you the total energy of the signal and to get the (average) power, you all need to divide by $4T_s$ – Dilip Sarwate Mar 28 '20 at 3:12
• @DilipSarwate - Perfect. Thanks. If you want to post an answer to this question I can mark it correct. – user1068636 Mar 28 '20 at 3:13