| 摘要 |
<p>1. Transmitter, especially short-wave transmitter, which can be tuned in a wide frequency band and having a push-pull final amplifier, preferably transistor amplifier, and a filter arrangement provided between the final amplifier output and the transmitter output, the subfilters (TP1...TPn) of which filter arrangement, which are associated with certain component frequency ranges of the transmitter working frequency and serve to suppress undesired harmonics of the transmitter working frequencies, can be switched into the signal path alternatively on the input side and output side via electrically controllable switches (S11, 512...) depending on the transmitter working frequency, characterized in that the subfilters (TP1...TPn) are dimensioned solely for a sufficiently large stop band attenuation of the harmonics n . fo of the transmitter working frequency to which are even multiples (n = 2,4...) hereof, and in that the required stop band attenuation for harmonics n . fo that are odd multiples (n = 3,5, ...) of the transmitter working frequency fo is produced by additional switching into which, the signal path of at least one further subfilter, in this case, related to the component frequency range determined by the transmitter working frequency fo, is associated with the component frequency range adjoining this component frequency range in the direction of increasing frequencies.</p> |
