| 摘要 |
<p>A filter circuit is primarily intended for use with duplexors associated with mobile transmitters, working in the centimetric and metric wavebands. The filter characteristics provides a pass-band and a high level of attenuation for narrow side-bands. The filter is based on the use of a bifilar line having a performance equal to that of a coaxial cavity. The line consists of a helix of gold plated wire wound onto a dielectric former (1), one end of the helix being connected electrically to an overall screening can (8). The remaining end (19) is brought out through the can (6) via a slot (17) in a dielectric shroud (3) which is altered in position with respect to the coil by a centre screw (18) such that the line length becomes equal to n lambda/2.</p> |
