Re: [Discuss-gnuradio] Frequency modulation in GRC

[Marcus Müller]

Ali,

again: there is no center frequency in a baseband simulation. Your sawtooth-repeat combination will give you a step signal, where the amplitude is constant for 500 items. All frequencies that you set are only used to calculate what will happen in one sample.

The frequency mod is but an input amplitude controlled complex sine.
It outputs a signal, which has a momentary phase increase that is proportional to sensitivity and input amplitude; see the doxygen documentation for the frequency_modulator block.

Greetings,
Marcus

On 24.05.2014 09:47, jason sam wrote:

Correction not 50 Hz but whatever the rate is after interpolation


On Sat, May 24, 2014 at 12:23 PM, jason sam <address@hidden> wrote:

Another question related to my flowgraph  that when i use the' Frequency
Mod' block...then it will take the center frequency as 50Hz(the freq of the
signal coming in)??


On Fri, May 23, 2014 at 1:28 PM, Ron Economos <address@hidden> wrote:

I was experimenting with this the other day. I used
the wide band FM modulator instead, since the
deviation can be set. Here's the flow graph.

http://www.w6rz.net/fmtest.grc

The test audio files. sine01.wav is 0.1 Hz and
sine15k.wav is 15000 Hz.

http://www.w6rz.net/sine01.wav

http://www.w6rz.net/sine15k.wav

Some C code to generate audio files at other frequencies.

http://www.w6rz.net/sine.c

Ron



On 5/22/2014 9:26 PM, jason sam wrote:

Hi,
I have made the flowgraph as attached..It is showing the modulation in
scope but in fft block it's continuously changing  so I am still unable to
find out that what are the max and min frequencies??I know how to find that
in theory but i want to prove it from my results..

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