Re: [Discuss-gnuradio] Amplitude settings in uhd_siggen

[Marcus Müller]

Ah well, in that case, the energy of only one increased subcarrier will,
due to Parseval's Theorem, still be present in the time signal, but be
split across all samples in the OFDM symbol (IDFT).

Anyway, in a practical system you'd limit the power-per-subcarrier, so
that no combination of subcarrier symbols can lead to time domain peaks
that get clipped.

Greetings,
Marcus

On 02/11/2015 12:12 PM, Ron Economos wrote:
> On 02/11/2015 03:05 AM, Martin Braun wrote:
>> On 02/11/2015 10:38 AM, zealdeal wrote:
>>> Is this clipping behaviour specific to uhd_siggen? Earlier I have
>>> tried to
>>> increase the amplitude of an OFDM subcarrier to more than 1.0 and
>>> saw linear
>>> increase in received amplitude. Clipping took place at quite a high
>>> amplitude.
>> No, 1.0 maps to FS for USRP blocks. In the OFDM example, watch the
>> amplitude of the signal before it enters the USRP sink. If it exceeds
>> 1.0, I promise it will clip (and you will see this with a spectrum
>> analyzer).
>>
>> M
> zealdeal could be talking about the amplitude of an OFDM carrier
> before the IFFT.
>
> Ron
>
>
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