An apparatus includes a first mixer performing first mixing of an input signal with a digital carrier which rotates the input signal such that one end of a target bandwidth in the input signal is aligned with an edge of a first bandpass filter that performs a first filtering on the first mixed input signal; a second mixer performing a second mixing of the first filtered input signal with a digital carrier which rotates the first filtered input signal such that the opposite end of the target bandwidth is aligned with an edge of a passband of a second bandpass filter that performs a second filtering on the second mixed input signal; and a third mixer performing a third mixing on the second filtered input signal which rotates the second filtered input signal such that the target bandwidth returns to the target bandwidth prior to the first mixing.