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

Cosy MUTO  Hiroshi HOSHIKAWA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.2   pp.309-315
Publication Date: 2002/02/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
image rejection,  software radio,  complex filter,  complex leapfrog,  variable characteristics,  

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In this paper, we discuss an IF image rejection system with variable bandwidth and center frequency. The system is consists of a pair of frequency mixers multiplied by the complex sinusoid and a complex analog filter. By employing the complex leapfrog structure using OTA-C configuration and the frequency transformation from the normalized LPF, the proposed system is capable of variable bandwidth and center frequency characteristics. SPICE simulations result more than 43 [dB] image rejection is achieved for 6 [kHz] and 12 [kHz] bandwidths at 50 [kHz] IF.