Electrical engineering

Signals and logic

Fourier sketch, sampling, Boolean algebra.

Basics

Frequency view

A periodic signal can be a sum of sines. Filters pick bands. Noise spreads in the spectrum. Communications ride information on a carrier (AM/FM/digital modulation).

Boolean algebra

AND, OR, NOT, De Morgan. Combinational logic has no memory; sequential uses flip-flops and state. A clock synchronizes. Twos-complement addition is the usual integer arithmetic.

Formulas

Channel capacity (sketch)

C = B log₂ (1 + S/N)

An upper bound on bit rate given bandwidth B and SNR.

Symbols

  • B bandwidth (Hz)
  • S/N signal-to-noise power ratio

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