|After clicking OK three times to close dialogs, please left-click on BTWLPF
to select it and right click to choose "Open a Monitor".
Then its frequency response appears. Please choose Tools -> Save Coefficients on the menu.
You can save the coefficients into an appropriate directory.
Let's open the file. You may find "b1" exceeds the limit of signed 16-bits, that is -32768 to +32767.