In high-frequency applications, reflections occur if signals are not properly terminated. Figure 7-3 shows a properly terminated signal and Figure 7-4 shows an improperly terminated signal.

Figure 7-3 Properly Terminated Signal

Figure 7-4 Improperly Terminated Signal

To minimize reflection, use coaxial cable with matching characteristic impedance to the signal source. Terminate the other end of the cable with the same value terminator or resistor. For commonly used cables, RG59 has a 75‑Ω characteristic impedance, and RG58 has a 50‑Ω characteristic impedance.