Re: [Discuss-gnuradio] Serial to parallel conversion

[rear1019]

On Thu, 13 Jun 2019 at 09:22:21 +0200, Sneha vasan wrote:
> Yes I am implementing the OFDM receiver.
>
> So the idea is to do the serial to parallel conversion of the received
> signal at USRP source, So my question was, in order to do so can I use
> vector to streams block?? . As per the above suggestion the block does
> not really exist.

That’s correct. S/P- and P/S-conversion blocks to not exist in GNU
Radio. As Marcus commented, the usage of these blocks in text books is
only a convention to say “take N items and process them as a block at
once”.

> Instead, I can directly convert the stream output( from USRP source)to
> vector block for FFT implementation.

Yes: In order to connect a stream output (e.g. USRP source) with a
vector input (e.g. FFT block) you must a stream to vector block in
between.

Important note: Simply connecting a USRP source with a FFT block does
not suffice to make an OFDM receiver. You must perform synchronisation
(at least time and frequency, possibly even sample rate) and remove the
cyclic prefix before performing the DFT.

> Based on what the vector length and the number of items  values in the
> stream to vector block needs to be assigned

The vector length (= “Num Items” parameter of the stream to vector
block) is determined by the DFT size used.