| distribution of quantised noise | uniformly distributed if D small = D^2/12 |
| power of signal | 1/T x integral(f(t)^2)) |
| abs function in an integral? | split into -inf to 0 and 0 to inf |
| how to draw nyquist diagram | gain = radius, phase = theta |
| impulse response of second order system | e^-at x sinWn as per mechanics databook |
| step input for 1st order system | given by |
| pole at 0 - bode diagram | initial slope of -20 and sub in value to find gain at a relevant frequency (ie close to where the second turning point is) convert to dB |
| duality | page 1 databook |
| abs function in an integral? | split into -inf to 0 and 0 to inf |
| negative transfer function | same magnitude, opposite phase |
| differential form of transfer function | times denominator over to the over side and convert so you still have d2x/dx2 etc |
| definition of dB | 20log_10(thing) NOT -ve, but 10 if power |
| multiplication in time domain | 1/2pi convolution in frequency domain |
| DFT gives frequencies spaced by 1/T where T is what | TOTAL SAMPLES NOT SAMPLING TIME |
| AM vs DSB | = |
| transmission rate of constellation in bits per second | = log_2(M)/(T per pulse) where M is number of symbols |
| energy in frequency domain (approx mainlobe) equals what, therefore how to calculate energy of frequency signal | equals energy in time domain, NOT with 2pi factor. If integrating the frequency domain to find energy, then divide by 2pi |
| how to demodulate DSSB | times by carrier frequency cosine wave. Pass through low pass filter with gain = 2/a where a is attenuation of signal. Cut off = bandwidth of useful signal |
| signal to noise ratio uses what dB conversion | 10 not 20 |
