Patent ID: 7403063

Claim:
A tuning apparatus for tuning a filter, the filter comprising a voltage-controlled oscillator (VCO) circuit, the tuning apparatus comprising: an enabling circuit, electrically connected to the filter, for controlling the filter to enter a tuning mode by disabling the entire filter except for the VCO and allowing the VCO to generate an oscillation signal according to a driving signal; and for controlling the filter to enter a normal mode from the tuning mode by enabling the entire filter to operate according to the driving signal when a frequency of the oscillation signal is equal to a reference frequency; a frequency detector, for comparing a frequency of the oscillation signal outputted by the VCO with the reference frequency to generate a comparison result; and a controlling circuit, electrically connected to the frequency detector and the filter, for adjusting the driving signal according to the comparison result in the tuning mode, and outputting the driving signal to the filter in the normal mode.