Tunable Filter

Tunable filter-  tunable filter model with vector fitting description.

Model for 2-port voltage control linear devices enables simulation in transient or CW mode, see Simcontroller.

Figure: Diagram block


Figure: Dialog box


  • Signal type: allows to configure the input signal as complex or real

  • Delta protection value: look for protection at -x dB (by default -10 dB) both below frequency and above the central frequency.
  • Mean type: select one of the two options used to determine the center frequency of the filter (normalization of the filter shape).
    • (f_protection_inf + f-protection_sup)/2 → constant band
    • sqrt(f_protection_inf x f-protection_sup)/2 → constant Q
  • The format is composed of a header indicating the block dimensions and a body containing Touchstone blocks or references to independent Touchstone file.

    Header

    #NB_PORT = number of ports: 2
#NB_FREQ = number of frequency points: nb_Freq
#NB_PARAM = number of design parameters: 1
#NB_PARAM_PTS = List of number of points per parameter: nb_1

#PARAM$1 = val1_1, ..., val1-nb_1 : list of parameter values
    Body: list of Touchstone files blocks :
  • External file reference preceded by #FILE statement 
    #FILE regular Touchstone-formatted data file name 
    (must be located in the same directory or subdirectory of the mail file)

  • Interpolation method: interpolation can be performed thanks to cubic spline or vector fitting method. Note that the method cubic spline is only compatible with a CW simulation. For vector fittingmethod, the user has access to the following settings and options:

    * Number of poles: user can specify 0 for automatic search or positive integer to fix pole/residu number* Pole fine tune: option that if activated tunes number of pole/residu from 1 to value specify in the previous parameter *Number of poles".
  • Control Parameter value: This is the value of the simulation which will be used for control the central frequency location of the filter.