Short Description of Syntfil Package

Text with red color describes facilities which are NOT INCLUDED in Syntfil light edition. These facilities are included only in full version of Syntfil package.

The package contains functions for design of of electric filters.

Set of functions for solving approximation tasks

• normalization - frequency transformation of lowpass (LP), highpass (HP), bandpass (BP) or band-rejection (BS) filter specifications to normalized lowpass filter (NLP),
• computation of the filter order for a chosen type of approximation (Butterworth, Chebyshev and Cauer ),
• computation of the Butterworth approximation,
• computation of the Chebyshev approximation,
• computation of the Cauer approximation (types A, B and C) and
• computation of the Inverse Chebyshev approximation (types A and B) .

results of approximation task are:

• secondary parameters of the filter,
• poles and zeros of gain and characteristic function and
• gain and characteristic function.

Set of functions for LC filter realization from gain and characteristic functions

• computation of the chain matrix from gain and characteristic function for a chosen load of filter,
• synthesis of LC ladder filter from chain matrix for polynomial and elliptic approximation,
• transformation of LC ladder structure of NLP to LP, HP, BP or BS (in light edition only LP and HP).

Set of functions for cascade design of active RC (ARC) filters

• frequency transformation of the transfer function poles and zeros of NLP to particular biquadratic transfer functions parameters of desired type of filter (LP, HP, BP or BS ),
• assignment of particular zeros to corresponding poles , so-called pole-zero pairing to biquadratic functions are formed,
• determination of order in which the biquadratic functions (biquads) should be cascaded,
• choosing of the optimum gain distribution to particular biquads and
• synthesis of basic biquad types, synthesis of more complex biquad circuits is available only in the full version of package .

Analysis of resulting filter structures

• analysis of LC ladder filter structures include Q-factors of inductors and
• analysis of ARC filter structures include DC open-loop gain and unity-gain frequency of operational amplifiers for all biquads circuit types used in the package.