A periodic signal f(t) is showed in the picture. For the amplitud modulation (AM), what should be the minimum amplitud of the carrier?
. For that Carrier amplitud, sketch the AM wave when the Carrier frequency is 100 KHz.
. Find out the AM wave spectrum
. Sketch the DSB-SC correspondent wave and its spectrum.
Please, i need to know how to desenvolve this, mainly the last item. Thanks
May I say that the minimal amplitud of the carrier be 1 V (for does`t have overmodulation)?
Since we consider the signal amplitud the peak signal (Vpp/2), what shoul be that amplitud?
The amplitude of the carrier should be 1V so that the negative going modulation does not clip.
This is a classical way to give higher power output and still keep within government regulations. The modulator supplies an extra DC to the modulated amplifier which increases the carrier power.
The government regulations usually state the limit on carrier power with no modulation. Once they got wise to this modulating method they made it illegal.
Yes a(t) should be converted into fourier series and by multipying the carrier you just shift the frequecies by the carrier frequency. That would be the spectrum of the resulting signal.
From your equation and attached waveform you can only find entire part of equation Eo+K*a(t) and not only a(t). Different parameter values for Eo, K and a(t) can give you the same waveform.