| 摘要 |
<p>A directional coupler comprises a main signal conductor (10), probes (13, 14) capacitively coupled to the conductor (10) at points spaced a quarter wavelength apart along the conductor (10), one probe (13) providing a first terminal (4), and a quarter wavelength line and a half wavelength line connected respectively from the probes (13, 14) to a second terminal (3). Signals on the first and second terminals (4, 3) represent the power of the forward and reverse signals, respectively, on the conductor (10), so that the ratio between these signals represents VSWR (voltage standing wave ratio). The two terminals may be connected to a logarithmic circuit giving an output proportional to the difference between the logarithms of the forward and reverse powers (therefore representing VSWR).</p> |
