GNUradio : stream data using multiply_cc()

Asked May 29 '17 at 14:26

Active May 30 '17 at 11:20

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I am using a USRP to transmit BPSK modulated data. To modulate, I use a 80 000 elements vector (vector_source_c format) which I want to multiply with the data (vector_source_c as well) I'd like to send.

My problem is that the data is important, so I'm trying to multiply it by slices with my vector, using the block multiply_cc(). I'm affraid the ultiplication is made only between my modulation vector and the 80000 first elements of my datam then repeated.

Is it how multiply_cc() works ? If true, is there a block I can use to multiply and stream ?

edited May 30 '17 at 11:20

asked May 29 '17 at 14:26

EllaStique

I don't understand your question. multiply_cc does exactly what the name suggests: it takes one item from both input streams and generates one output item, then the next, and so on. – Marcus Müller May 29 '17 at 20:21
I am affraid it could loop if one stream is smaller than the other and thus ignore the bigger stream. Is it possible ? – EllaStique May 30 '17 at 11:07
I don't understand that, either, sorry. – Marcus Müller May 30 '17 at 11:09
Sorry... If one stream is N bits and the other N x m bits = [N1, N2 ... Nm], and I try to multiply_cc() them, are we sure that the output won't be [N x N1 ... N x N1] instead of [N x N1 ... N x Nm] ? – EllaStique May 30 '17 at 11:16
by repeating each element of the first stream `m` times – that's what the *Repeat* block is for! – Marcus Müller May 30 '17 at 11:20
Oh, yes, thank you, I didn't think of that : this will remove the ambiguity on the multiplication – EllaStique May 30 '17 at 11:24
There's really no ambiguity at all! – Marcus Müller May 30 '17 at 11:42

GNUradio : stream data using multiply_cc()

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