Hi. I'm doing a lab where we hooked up an RF signal generator at 1.25MHz/10dBm to a spectrum analyzer using a 50 ohm wire. Can anyone explain to me or link me to a place where I can read about why a real sine wave's frequency spectrum is not a pulse? Also, why would with a sweep from 1 Mhz to 4 Mhz the SA show three sine waves separated by multiples of the frequency of the intended sine wave(~-10dBw @ 1.25, ~-66 dBw @ 2.5, ~-87 dBw @ 3.75)? Would there also be lowered amplitude frequencies to the left of the intended frequency? I'm pretty confused, because I haven't taken the signals and systems class that stresses frequency response, FFT, and so on. Also, I have no idea how this hardware works. I just want an informed lab report!