| 摘要 |
Some embodiments provide an oscillator that produces a signal at a desired frequency for use in a tuner. The oscillator comprises a filter and a frequency divider circuit comprising one or more frequency dividers in sequence, each frequency divider reducing a received frequency by a predetermined proportion. The frequency of the oscillator is controlled by a tuning code comprising a fine tuning code applied to the filter and a coarse tuning code applied to the frequency divider circuit. The filter is used to produce an initial frequency according to the fine tuning code and the frequency divider circuit divides down the initial frequency according to the coarse tuning code to produce a final frequency of the oscillator. Some embodiments provide an automated method and apparatus for tuning the oscillator to produce a signal at a desired frequency where the coarse tuning code is determined before the fine tuning code.
|
