Balanced structure design of intermediate frequency LC filter

Large insertion loss and no effect on the common mode interference are the technical bottlenecks of the unbalanced topology LC IF filter circuit in the application of high-speed mixed-signal circuit with the characteristic of a complex electromagnetic environment. This paper proposes a method of designing LC IF filter with balanced topology by analyzing the defects caused by unbalanced topology and compared the two methods with unbalance to balance transformer and the balanced topology when processing balanced signal and using Agilent ADS simulate with the characteristic of single-ended Elliptic prototype and its transmission characteristic to prove the effectiveness of this topology.