I'm using GRC v 3.6.0 and looking at what can be done with the standard library.
Although I've been able to apply FM to a wave, I'm still having issues understanding how to manipulate the variables. There is a Frequency Modulation block.. but i'm a bit confused about what line 55 http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/5d69a524f81f234b3fbc41d49ba18d6f6886baba/entry/gnuradio-core/src/lib/general/gr_frequency_modulator_fc.cc<http://gnuradio.org/doc/sphinx/gr/modulation_blk.html> >From what I understand, to get Linear Frequency Modulation, I need a parabolic change in phase. d_phase = d_phase + d _sensitivity*in[i] where (i believe) d_sensitivity is set constant and in[i] is an input source of samples >From what I gather from an earlier discussion thread if I put add a sawtooth input then I should get a Linear Frequency response? http://old.nabble.com/Generating-chrip-signals-td3985122.html I appear to be getting a LFM, when i try feeding a Source [Sample Rate of 25M, Sawtooth wave, Freq 1k, Ampl 1] into a Frequency Modulation Block [Sensitivity of 0.002] but I'm unsure how to manipulate the inputs. E.g. how would I set my values for d_sensitivity and amplitude to get my LFM to shift from a frequency of 1000k to say 2000k? Also, i'm a bit concerned that the sawtooth output doesn't appear to be linear :/ Is there a better way of doing this using existing blocks? Also what is the maths behind it.. i've just been beating my head against the wall on this one and I appear to be just missing something Please help! <http://gnuradio.org/doc/sphinx/gr/modulation_blk.html>
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