Signal generating appartus, filter apparatus, signal generating method and filtering method

A filter apparatus where input signals are sampled by different first capacitors in sequence, and at least a portion of the charge stored in the first capacitors when sampled is outputted, comprising:

• a multiphase oscillating portion for generating a number of base signals having the same frequency and a predetermined phase difference, where periods during which (1) any given base signal and (2) the next base signal having the phase delay relative to the given base signal are both kept at a first level overlap;
• a transition time point changing portion for generating a pulse signal by changing the time point when each of the base signals transition from the first level to a second level to the time point when or before the next base signal transitions from the second level to the first level;
• and
• a switching portion for allowing each of the first capacitors to sample the input signal in sequence on the basis of the number of pulse signals.

A filtering method which is implemented in a filter apparatus where input signals are sampled by different first capacitors in sequence and at least a portion of the charge stored in the first capacitors when sampled is outputted, comprising the steps of:

• generating a number of base signals having the same frequency and a predetermined phase difference where periods during which (1) any given base signal and (2) the next base signal having the predetermined phase delay relative to the given base signal are both kept at a first level overlap;
• generating a pulse signal by changing the time point when each of the base signals transition from the first level to a second level to a time point before the next base signal transitions from the second level to the first level;
• and
• making each of the first capacitors sample input signals in sequence on the basis of the pulse signals.