| 摘要 |
The invention concerns a tuning system for a receiver for the selection of a radio frequency (RF) signal from several receivable RF signals, comprising: RF devices TC-1, TC-2, LV-DTF, HV-DTF, UHF-DTF which have an adjustable frequency selective characteristic for reception of RF signals; an oscillator device L/-1 for generating an oscillator signal, the frequency of which is controlled by a first control signal for the selection of the abovementioned individual RF signal; a mixer device MX for superposing the RF-devices' RF signals and the abovementioned oscillator signal for generating an intermediate frequency IF signal with a predetermined frequency; a first control device for generating a first control signal for the selection of the abovementioned individual RF signal in such a way that the frequency of the abovementioned individual RF signal is changed to the abovementioned predetermined IF frequency by the action of the mixer device; a tuneable circuit device which is included in the RF devices for adjustment of their frequency-selective characteristics dependent upon the tuning signal and for generating the adjustment signal of the device. In order to minimize the mechanical tuning, the tuning system is characterized by devices NVM, PROM for generating a first component in the tuning signal, which first component has several values corresponding to adjacent corresponding groups of RF signals; device TC for generating a second component in the tuning signal dependent upon the selection of the abovementioned individual RF signal; devices NVM, PROM for storing the first component and excluding the second component; devices 51, 52, 53, R7, R8 for combining the first and the second components for generating a tuning signal and supplying the tuning signal to the circuit device which is to be tuned in order to achieve tuning of the frequency selective characteristic. <IMAGE>
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