2003 年 6 巻 6 号 p. 516-519
New measurement method for characteristic impedance of Printed Circuit Board was developed and its usability was demonstrated. This method is based on a conventional TDR method, but using burst sinusoidal wave modulated by step pulse as a input signal instead of direct step pulse. Characteristic impedances of 5m semi-rigid cable and 28cm Microstrip PCB are measured at 70 MHz-350MHz frequency randge using this new method. For the long cable the characteristic impedance can be measured consistently with the conventional method between 200MHz to 350MHz. For the short microstrip line however the measured values fluctuate in some extent. The reason for obtained results are discussed.