Hello Vasil and Marcin,
Thanks very much for your help.
I have all the relevant #include header files and invoke the low_pass filter as follows:
lpfilter = gr::filter::firdes::low_pass(gain, sampling_freq, cutoff_freq, transition_bandwidth,
fft::window::win_type::WIN_HAMMING, beta);
Observations:
Using the mouse to hover over WIN_HAMMING, I can see that it interprets the win_type enum variable and correctly assigns it a value of "0" (which is the value stated in the Gnuradio C++ API Reference manual). However, there is a squidly under beta. Hovering over beta, the error message is:
Argument of type "double" is incompatible with parameter of type "gr::fft::window::win_type"
If one of you has a working code fragment using one of the C++ Gnuradio filter methods that you can cut, paste and send in your next email I would appreciate it.
Thanks for your help.
George