basic question

Thread Starter

bhuvanesh

Joined Aug 10, 2013
268

WBahn

Joined Mar 31, 2012
30,076
Quite the contrary, it pretty much states that "sine wave" and "sinusoid" are synonymous. But there is some fine print involved.

Do you make a distinction between a sine wave and a cosine wave?
 

Thread Starter

bhuvanesh

Joined Aug 10, 2013
268
yes off course i can make distinction with sin is odd signal and cosine is even signal. I can distinct in this way
 

WBahn

Joined Mar 31, 2012
30,076
looks like both
Good answer. The key point is that whether it is a "sine" wave or a "cosine" wave depends entirely on when you choose to start your clock (i.e., what point you choose as your reference point for the independent variable). The waveform itself is the same, so in that sense they are really the same signal, it's just how we express it relative to our arbitrarily chosen reference that differs.

So "sinusoid" is the generic term and applies to either sin() or cos() with an arbitrary phase angle. While sin() and cos() with zero phase angle can be viewed as being "different", but only if there is a specified reference point (i.e., t=0). Whether we make a distinction or not depends on the context of the discussion. We can break an arbitrary sinusoid into the sum of a sin() and cos() (with zero phase angle). In general, we can do this regardless of where we place our reference. This is known as decomposing them into a pair of quadrature-related signals.
 
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