Re: [Discuss-gnuradio] OFDM cyclic prefixer

[Ron Economos]

If you haven't already, you may want to take a look
at this GnuRadio DVB-T implementation.

https://github.com/BogdanDIA/gr-dvbt

Ron

On 5/14/2014 1:50 PM, Yuri P.M wrote:

Hi,

Thanks Mr. Economos and Mr. Braun,

I left this parameter in blank (I guess this is the same as an empty string), it seems that it is working now.

Actually I am trying to modulate ISDB-T data stream. I am working with vectors, instead of data stream.

Thanks again.

2014-05-14 5:28 GMT-03:00 Martin Braun <address@hidden>:

On 14.05.2014 04:36, Ron Economos wrote:

If you're sending packets, then Length Tag Key should be
set to the packet length you're using. If you're sending
a stream (like DVB-T), then this field is not used (and
left blank).

It needs an empty string, in this case.

The OFDM cyclic prefixer is used after the (reverse)
FFT block. The FFT Length in the OFDM Cyclic Prefixer
block should match the FFT Size in the FFT block.

That's right. The block doesn't check if the input is actually OFDM.

Martin

Ron

On 5/13/2014 6:06 PM, Yuri P.M wrote:

Hello,

My name is Yuri.
​ I very new to GNU Radio, and I'm using GRC 3.7.1.​


I am doing a research, and I need to modulate specific signal in OFDM.
I would like to insert cyclic prefix (or guard interval in my project,
the same thing with a different name).

I looked at the examples
​under gr-digital
​/examples/ofdm, and I've also read some papers about OFDM technics.

My doubt is: what is the parameter "Length Tag Key"? I've seen it
working in the examples located in the folder above, I've tried to do
the same in my project, but it states a message that this parameter is
missing.

By chance, does this cyclic prefixer block only works with other
blocks of the same category? I mean, do I need to use OFDM carrier
allocator before it, or something like that?

Thank you for your attention,

Yuri.