EM-528K HDI PCB The signal may cross the logic level threshold many times during the transition, resulting in this type of error. Multiple crossing logic level threshold errors are a special form of signal oscillation, that is, signal oscillation occurs near the logic level threshold. Multiple crossings of the logic level threshold will cause logic function disorder. Causes of reflected signals: excessively long traces, unterminated transmission lines, excessive capacitance or inductance, and impedance mismatch.The following is about EM528K HDI Circuit Board related, I hope to help you better understand EM528K HDI Circuit Board.