| 摘要 |
An in-line bandstop filter for rejecting 4G mobile phone signals in a TV receiver comprises earthed quarter-wave ceramic resonator stubs 22 and series coil inductors 18 coupled as delay elements between the resonator stubs 22. The interfering 4G signal band may be just above the TV frequency band, and so the filter must provide a sharp transition at its lower frequency edge. The required sharp transition may be achieved by selecting inductor values that provide transmission poles near to the edge of the stopband (TP, figure 2). |
