| 摘要 |
PROBLEM TO BE SOLVED: To provide a programmable digital filter whose characteristic is stable irrespective of a variance in characteristics of components and capable of processing a signal over a wide band. SOLUTION: The programmable digital filter is provided with: an A/D converter 102 for converting an analog input signal into a digital signal, the analog input signal being an IF signal with an intermediate frequency subjected to band limit by a low pass filter 101a; a down-converter 103 provided with a digital quadrature detector for converting the digital signal received from the A/D converter into baseband I, Q signals orthogonal to each other and whose phases are deviated by 90°; a digital up-converter 105 provided with a digital quadrature modulator for up-converting the baseband I, Q signals outputted from the down-converter; a D/A converter 106 for converting the digital signal outputted from the digital up-converter and modulated into an analog signal; and a low pass filter 101b through which the analog signal passes, and the digital down-converter and the digital up-converter form a programmable digital filter body. COPYRIGHT: (C)2005,JPO&NCIPI
|
