Article

Article title COMPLEX QUADRATURE FILTER
Authors V.V. Khristich
Section SECTION II. IP-CORES MIXED-SIGNAL SYSTEM ON CHIP
Month, Year 05, 2014 @en
Index UDC 621.372.54
DOI
Abstract The mathematical description of complex quadrature filter (CQF) is given. Offset between center frequency and modulation frequency is implemented in this filter due to the interchannel links. It’s shown that value and sign of frequency offset are defined by the coefficient values of the links between similar units of low-pass filters (LPFs) from different channels. Presence of controlled frequency offset extends the quadrature filter facilities and enables signal processing accuracy increasing. Circuit implementation of the channel LPFs is proposed as the quasiladder structure consisting of multiinput integrators with differential output. This allows identical channel circuits with different coefficient signs of interchannel links. The expressions are given for the channel LPF design in compliance with the given requirements to the gain- frequency characteristic of the CQF. The results of the CQF experimental researching with using of Micro-Cap application are given. The researching confirmed the validity of the pro- posed CQF mathematical description.

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Keywords Quadrature filter; channel filter; modulation frequency; frequency offset; transfer function; gain-frequency characteristic.
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