An Integrable Image Rejection System Using a Complex Analog Filter with Variable Bandwidth and Center Frequency Characteristics

摘要

In this paper, we discuss an IF image rejection system withvariable bandwidth and center frequency. The sys- tem is consists ofa pair of frequency mixers multiplied by the complex sinusoid and acomplex analog filter. By employing the complex leapfrog structureusing OTA-C configuration and the frequency transformation from thenormalized LPF, the proposed system is capable of variable bandwidthand center frequency characteristics. SPICE simulations result morethan 43 dB im- age rejection is achieved for 6kHz and 12 kHzbandwidths at 50 kHz IF.