 Gigahertz

A gigahertz is $10^9$ hertz, or $10^9$ cycles per second. The prefix giga supplies the exact factor $10^9$. A periodic signal at $1\mathrm{GHz}$ has period $T=1/f=1\mathrm{ns}$.^[ref]

The corresponding angular frequency is $\omega =2\pi f$, so $1\mathrm{GHz}$ means $2\pi \times 10^9\mathrm{rad}{\mathrm{s}}^{-1}$. Keeping this distinction explicit prevents a factor of $2\pi$ error in wave and oscillator equations.