Phase of signals in two-tone test of amplifier

In the two-tone test of amplifier, baseband signals (w2-w1 and w1-w2) will be generated at the output.

Does anyone know the phase of these two signals (w2-w1 and w1-w2) should always 180 degrees out of phase? Or, when the phase of w2-w1 is θ degrees, the phase of w1-w2 should be -θ degrees?

Thanks!

Well, if the two tones are expressed as:

A1 sin( w1t + Θ1) and A2 sin( w2t + Θ2)

then the output will have sin( w1t -w2t + Θ1 - Θ2) and sin( w2t -w1t + Θ2 - Θ1).