| 摘要 |
<p>Disclosed is a common-mode filter that passes ultra-fast differential signals and impedes common-mode noise. A lumped-constant differential delay line (DL), in a ladder-type differential four-terminal circuit comprising passive series elements and passive parallel elements placed in differential lines (1, 3), is formed by placing inductors (Ls) in the passive series elements and capacitors (Co) in the passive parallel elements. For the inductors (Ls) in the passive series elements, inductors forming a pair in differential lines within the same interval are made to have mutual inductance. For differential signals, differences between the inductances of the inductors (Ls) and the mutual inductance (m) are made to function as series elements. For common-mode noise, sums of the inductances and the mutual inductance are made to function as series elements. For the lumped-constant differential delay line (DL), inductors (L1 to L4) and resistors are connected between connection nodes (T1-T4), which are between capacitors (Co/2, Co/2, or Co, Co), and a ground potential, forming a common mode noise attenuation-use attenuation pole.</p> |
