Quartz Ladder Bandpass Filters
Joachim Köppen DF3GJ ... Kiel, July 2016

Some brief explanations

• This tool is the JavaScript version W7ZOI's method to design ladder bandpass filters with quarz resonators with measured properties.
• One enters the design data in the text fields, and hits the compute button or the Enter key
• The plot shows (one half of) the frequency response of the filter.
• The table below gives the values for the shunt capacitors
• The bandwidth field turns yellow, if the terminating resistance or any of the capacitors turns out to be negative, hence it is impossible to construct the filter.

Crystal parameters:
    unloaded Q = 140000
    motional C = 17.12 fF
    motional L = 76.4 mH

The filter:
    terminating resistance = 833.5 Ohm
    the shunt capacitors are:
    C12 = 33 pF

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