Hi Marcus, Yes. I understand that I need to be more specific in the subject. Thanks for correcting.
When I use the signal source block, although its already digital, I thought I must specify sampling rate as per Nyquist condition in the "samp_rate" variable. (Suppose the tone is 10 kHz, then I must give more than 20 kHz as sampling rate). For the USRP sink, "center frequency parameter", I understood that I can specify the carrier frequency that carries the baseband signal. But I also observed that if I change the variable samp_rate, it changes throughout in all other blocks as well. So it must be a global parameter and not necessarily the Nyquist sample rate as I thought it to be! Request you to kindly explain. When I multiply two signals and plot the FFT, the plot mentions dB for the frequency components. You already corrected me earlier that its not power. Then what does this dB mean? regards Nirmala On Mon, Nov 6, 2017 at 3:37 AM, Marcus Müller <muel...@kit.edu> wrote: > Hi Nirmala, > > could you try to use descriptive subject lines in the future? I took the > freedom of changing yours, so that people know what your mail is about, in > hopes you get better answers that way! > > Anyway, Ben is right, you should probably start with the established > tutorials at http://tutorials.gnuradio.org. > > Your task > > First I want to send a simple tone within 20 kHz, sample it and transmit > with a high frequency carrier in the ISM band and receive it. > > does sound very feasible for someone who's read the first few chapters of > that, although > > First I want to send a simple tone within 20 kHz, sample it > > is a bit misleading: your tone is a digital signal, as it gets created > within your PC; you can't sample it, it's already digital :) But seriously, > you can generate a 20kHz with a single block (signal source), and actually > send it by connecting that block to e.g. a USRP Sink (if you have a USRP). > But you said you wanted a simulation, so I'm a bit left to wonder what to > simulate – you see, GNU Radio (and software defined radio) often, if not > usually, deals with *equivalent baseband* so that we don't actually *care* > about the carrier at all, but model all things that happen in the RF > passband as happening in baseband. So, your choice for a first simulation > seems a bit unusual, if not even slightly unlucky. > > Best regards, > Marcus > >
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