| 摘要 |
A transmisson device for transmitting a wanted signal (NS) modulated on a carrier (TS) has a band filter connected in the transmission path (2) of the transmission device (1) and tuned with the frequency (F(T)) of the carrier. An error signal circuit (9) influences the band filter, recognizing oscillations generated at the band filter whose amplitude remains below a set limit value (SW) set in the error signal circuit, and generating an error frequency signal (FS) representative of the frequency of occurrence of the recognized oscillation errors. A quality adjusting circuit (7) which adjusts the quality (G) of the band filter is connected to the band filter (5) and the error frequency signal (FS) is supplied to its adjusting input. When the error frequency signal is missing, a first filtering quality (GO) is adjusted at the band filter on the basis of a quality conversion characteristic (10), setting a band width (Bf18) at the band filter at least equal to the predetermined transmission band width for the wanted signal (NS) to be transmitted. When an upper value (FSn) of the error signal (FS) is generated for a determined error rate yet to be regulated, a second filtering quality (GM) is adjusted at the band filter on the basis of the same quality conversion characteristic (10), setting a determined voltage magnification of the carrier oscillation (TS) at the output of the band filter. |
