Newbie questions

Hello,

I’m new into gnuradio, so sorry in advance for the very basic
questions. I’m trying to read the code whenever possible but it takes
times to get used to it :slight_smile:

I’m playing around with the wfm receiver, adding time domain scopes,
trying to get the stereo out (yes I saw someone has done it before :wink:
), new slide bars etc… just playing around to get familiar with the
beast in other words.

First, I’m trying to understand why I don’t get the whole 100khz band
when I plug an fft_sink_f to the self.guts.deemph.
I only get from 0 to 16kHz whereas I was expecting to get something
close to:

Could someone explain?

Also could someone explain the cutoff values from (and what is the
passband ripple parameter using an intuitive explanation) from:
chan_filt_coeffs = optfir.low_pass (1, # gain
usrp_rate, # sampling rate
80e3, # passband
cutoff
115e3, # stopband
cutoff
0.1, # passband
ripple
60) # stopband
attenuation

why 80k and 115k?

Next, I’m trying to build a double slider for the frequency. One slider
to set a rough frequency, and another slider to fine tune it more
precisely. Kind of two synchronized sliders which get both updated (as
well as the textbox with the exact frequency value) when one is moved.
Is there any example around I could get inspiration from (I’m not
familiar with wxWindow yet).

And finally I would like to extend it to be able to choose between
different modulation mode (AM, CW, WFM…)
I wonder if I should start looking at the mblock for that, given the
dynamic graph capability (from what I understood by reading the ML,
with the mblock we can unplug block and replug new one in real time,
which seems to be suitable in this case). Or maybe there is an easier
solution?

I think that’s pretty much it for my first day of experiment,

Thanks for any pointers you could provide,


Best Regards,
ChoJin

On Thu, 10 Jan 2008 17:27:25 +0100, ChoJin wrote:

[…]

Next, I’m trying to build a double slider for the frequency. One slider
to set a rough frequency, and another slider to fine tune it more
precisely. Kind of two synchronized sliders which get both updated (as
well as the textbox with the exact frequency value) when one is moved.
Is there any example around I could get inspiration from (I’m not
familiar with wxWindow yet).

I finally manage to get this part done


Best Regards,
ChoJin