Patent ID: 7023293

Claim:
A radio filter being operable in a frequency range comprising: an input connection, an output connection, and at least two resonator modules, each of said at least two resonator modules having a tuning mechanism, said filter being adapted to receive at least one signal, having a frequency content, being within said frequency range, wherein at least two of said resonator modules are coupled in cascade, whereof a first resonator module being connected to said input connection and a final resonator module being connected to said output connection, at least said final resonator module having a probe for measuring a signal parameter at the final resonator module, and said filter further comprises a control unit which is connected to said probe, which is adapted to sense the frequency content of said received at least one signal, and to said tuning mechanisms, which are automatically adjusted to a tuning value by control signals which depends on the sensed frequency content for coarse tuning and the measured signal parameter at the final resonator module for fine tuning, the control unit comprises: a memory for storing information regarding a relationship between the position of the tuning mechanism for each resonator module and the frequency content of said received signal(s), which information is used to automatically coarse tune the filter, and a CPU, which processes the frequency content by using the information regarding the relationship between the position of the tuning mechanism for each resonator and the frequency content to provide said control signals for coarse tuning said filter, wherein said memory further comprises information regarding a set value vector comprising a set value for said signal parameter at each resonator module and information regarding a relationship between said set value vector and said measured signal parameter(s), where said CPU processes the measured signal parameter(s) by using the information regarding the relationship between the set value for each resonator and the measured signal parameter(s) to provide said control signals for fine tuning said filter.