Re: [Discuss-gnuradio] Frequency response from fading simulator block not working as expected

[Ricardo Yoshimura]

Hi Martin,

That´s right! As the number of taps was increased, the deep fadings were visible, ranging until about 20dB.

Thanks and Regards,

Ricardo

On Sat, Mar 1, 2014 at 8:51 AM, Martin Braun <address@hidden> wrote:

On 02/28/2014 02:13 PM, Ricardo Yoshimura wrote:
> In order to simulate a multi-path scenario, I´m trying to validate the
> "Frequency Selective Fading Model" block, but the results I found are
> not the ones I would expect.
> The set up consisted of 2 taps delayed 20 microseconds each other, so
> that the frequency response should have very deep fadings spaced
> regularly in frequency. The results I got showed a flat frequency
> response, as well as in other standardized power delay profile scenarios.
> The blocks I used were a random source -> OFDM Mod -> Throttle ->
> Frequency Selective Fading Model -> WX GUI FFT Sink. Sample rate was set
> as 1MHz, so that in Freq. Selective block I set PDP Delays as [0, 20]
> and PDP Magnitudes as [1, 1].
> Please tell me if I misunderstood any of these parameters or this block
> could be really improved.

Did you increase the number of taps?
Also, note that this block provides a time-variant channel. If you
average, you might not see fades. For a static channel, use the "Channel
Model".

If you use the default settings, you should see fades, right?

M

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