Ekko,

 

Are you trying to test this out initially over the air? If so, you may consider 
just running this through a script to itself without going over the air.  This 
would remove all possibility for interference and environmental black magic.

 

As far as testing what I am talking about, start by simply adding bytes to the 
file you are trying to send.  White space, or a specific character, or whatever 
you want.  Run this through the system.  Once you add enough extra bytes, you 
will eventually see your entire wanted data.

 

This is not a good final solution however.  With this you will run into a 
problem sending multiple things back to back and you will have to deal with the 
packetizer input buffer on the TX side holding onto the extra added bytes and 
prepending them onto the next thing you want to transmit.

 

The better solution would be to do what Marcus suggested.  This would be adding 
something before the packet encoder step that will ensure the data moving 
through the system has enough bytes for the packet encoder to do what it needs 
to.  This is up to you as how and where to implement, but the bottom line you 
need to be aware of is the number of bytes that are required to generate a 
chunk of packets and that your data needs to be an exact multiple of this 
number.

 

Hope this is helpful,

 

Michael

 

From: Ekko [mailto:[email protected]] 
Sent: Thursday, January 07, 2016 5:13 AM
To: Michael Berman <[email protected]>
Cc: [email protected]
Subject: Re: [Discuss-gnuradio] how to send a complete file

 

hello Michael

 

as you said,there are not enough data to feed the packetizer ,

 

now i use the dest file(generated by the same grc) as the source ,

1--->i think that the dest is generated by the grc,so the data in dest file 
must can feed the packetier, is it right

 

when i use dest file (generated by the same grc,now called A) as source file,to 
run my grc ,i got a new dest file (called B)

 

i campare the data in A and B

there is also some data lost. if my guess no.1 aboved is right ,

the data lost may not be caused by ( there was not enough data in the file to 
feed the packetizer)

 

hope for your correct.

 

thank you 

 

--Ekko

 

2016-01-07 2:26 GMT+08:00 Michael Berman <[email protected] 
<mailto:[email protected]> >:

Ekko,

 

It has been a while since I have dealt with this kind of issue with the digital 
coms, but I have run into this.  The problem I found was that there was not 
enough data in the file to feed the packetizer properly.  There are probably 
several work arounds for this, but the simplest would be to pad the data up to 
the exact amount the packetizer needs to generate the packets and send them 
along.  You can check if this is the case by varying the size of your file.  If 
you change the number of bytes in the file, you should see the amount left out 
varying; if you add bytes slowly you should see a breakover point near a 
multiple of the number of bits the packetizer needs that will create a small or 
no amount of data not transmitted.

 

Michael

 

From: [email protected] 
<mailto:[email protected]>  [mailto:discuss-gnuradio-bounces+mrberman87 
<mailto:discuss-gnuradio-bounces%2Bmrberman87> [email protected] 
<mailto:[email protected]> ] On Behalf Of Ekko
Sent: Wednesday, January 06, 2016 9:01 AM
To: [email protected] <mailto:[email protected]> 
Subject: [Discuss-gnuradio] how to send a complete file

 

hello

 

I'm using gnuradio to simulation the gmsk tx/rx with a file

this is my grc



 

you can see ,i am using a file_sink and file_source,

the file_source is set to not repeat,i want to send this file ony one time.

 

and my source file‘s size is 140KB

 

after i run this grc (i am sure the send is stop )

 

i check the dest file,the size of whitch is 139.3KB

 

then i compare two file

just like


​

we can see that some data is lost(exactly 22 lines),

so i want to know how can i send a complete file, just i send 140KB,and 
recieved 140KB,

then stop.

 

 

thank you

 

-Ekko​

 

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