Re: [Discuss-gnuradio] Error using Packet Encoder --> Packet Decoder

[Surya Agam]

I try different "random" access code and preamble but the output still 0kB.
Would you mind to give an example or reference about it?

On Sun, May 24, 2015 at 2:09 AM, Surya Agam <address@hidden> wrote:

Would you mind to give an example or reference about it?

I try random bit but I still have nothing.

Surya

On Sat, May 23, 2015 at 2:57 PM, Laur Joost <address@hidden> wrote:

I'm away from my computer right now, so I can't verify anything. But here's what I remeber from getting it to work.

For testing whether it works, just set them to a bunch of 1-s and 0-s.
Preamble is used by the demodulator for carrier and symbol timing recovery, so it should have many transitions and be long enough to give the recovery loops time to lock (I think I tried 32 bits and it worked).
Access code is used to detect the start of packet after the preamble, so it should have low autocorrelation, i.e. it should be as different as possible from shifted versions of itself (Meaning, don't set it to 10101010. It could work when simulating perfect signals, but it's a Bad Idea).

There are criteria and methods for selecting good ones for both, check the relevant Wikipedia articles for relevant articles :D

All the best
Laur

23.05.2015 9:49 kirjutas kuupäeval "Surya Agam" <address@hidden>:

I leave it blank. My setting for Encoder is
Sample/Symbol = 2

Bit/Symbol = 1 (based on documentation for BPSK)

preamble = blank

access code = blank

USRP pad = no

Payload Strength = 0

My Decoder

Access code = blank

Threshold = -1

How to set the preamble and access code?

Surya

On Sat, May 23, 2015 at 11:37 AM, Laur Joost <address@hidden> wrote:

Have you set the preamble and access code? The "leave blank for automatic" didn't work for me.

Laur

23.05.2015 6:53 kirjutas kuupäeval "Surya Agam" <address@hidden>:

Hello everyone,

I want to simulate file transmission using BPSK modulation, with block diagram

File Source --> Packet Encoder --> BPSK Mod --> BPSK Demod --> Packet Decoder --> File Sink

But the result is 0 kB. Then I remove the Encoder-Decoder and Modulation block.

File Source --> File Sink

Then I have the file and it's operable (-5 bytes from original file)

Next step I add Packet Encoder - Decoder

File Source --> Packet Encoder --> Packet Decoder --> File Sink

But the file size is 0 kB

I don't know what is wrong with the Encoder-Decoder.

Thank you

Regards, Surya Agam

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Sincerely,

Surya Agam

University Al Azhar of Indonesia, Jakarta