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| 🇬🇧 | 🇬🇧 |
| 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 |
| 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 |