Serina,
Amplitude modulation is typically defined as the result of multiplying the carrier signal by the modulating signal. An offset is usually included to prevent phase reversals at the zero crossings of the modulating signal. v(t) = Ac*sin(fc*t)*(1 + Am*sin(fm*t)). Am < 1 to prevent overmodulation (the phase reversals).
It appears that your VI is attempting to create the modulated signal by generating the various components which come from applying trigonometric identities to the usual mathematical expression for amplitude modulation and combining them.
The graph called Modulation Signal appears to be the product of the two sidebands of the AM signal. Mathematically it is the difference of the second harmonics of the carrier and modulating signals. This signal never appears explicitly in a standard AM transmitter.
The way the VI is configured, overmodulation is not possible.
Lynn
