PSYCH 3A03 Lecture Notes - Psych, Large Deviations Theory, Spectrogram
Document Summary
Amplitude modulation can also occur by modulating the amplitude of a single sine wave. Let a vary sinusoidally as a function of time: a(t)=[1+msin(2 fmt)] Spectrogram: shows the spectrum (frequency) and timing information. Amplitude can be shown by the thickness of the line. Amplitude information is colour coated on a frequency vs. time graph. Used as a masking signal or to control background noise or making sure that we are not providing any amplitude. Mean energy is centered on 0 but there are large deviations. Amplitude: instantaneous amplitude signal is random within specified frequency band. Narrowband noise (nbn): relative signal bandwidth is small. Wideband noise (wbn): relative signal bandwidth is large. Shaping the noise with different frequency envelope. Gausian noise can also be amplitude modulated. Rectification: all amplitudes as positive by taking the square. Amplitude of all sinusoidal components in noise signal. Average noise intensity in a band of noise 1hz wide.