Hi,
the problem is that the string "packet decoding" doesn't appear anywhere
in the current GNU Radio source code, so I'm still not sure which block
you are using. Also, crc.check_crc32 is used in two different blocks, so
I can't even tell this way what we are talking about :(
Can you actually make sure twice you got the letter-for-letter right
name of the "packet decoding" block?
Best regards,
marcis
On 21.02.2016 13:38, SangHyuk Kim wrote:
> Thank Marcus.
>
> "packet decoding" recovers message from received packet
>
> and i got false from crc.py
>
> def check_crc32(s):
> if len(s) < 4:
> return (False, '')
> msg = s[:-4]
> #print "msg = '%s'" % (msg,)
> actual = digital.crc32(msg)
> (expected,) = struct.unpack(">I", s[-4:])
> #print "actual =", hex(actual), "expected =", hex(expected)
> /*print actual == expected*/
> return (actual == expected, msg)
>
> 2016-02-21 20:52 GMT+09:00 Marcus Müller <marcus.muel...@ettus.com
> <mailto:marcus.muel...@ettus.com>>:
>
> Dear Sang Hyuk Kim,
>
> what "packet decoding" are you specifically talking about, and
> could you show us the code you've modified?
>
> Best regards,
> Marcus
>
>
> On 21.02.2016 12:32, SangHyuk Kim wrote:
>> Hi, I transmit simple text file using two USRP N210
>>
>> Tx)
>> file source -> packet encoding -> mod(GMSK) -> usrp sink
>>
>> Rx)
>> usrp source -> demod(GMSK) -> packet decoding -> file sink
>>
>>
>> To make corrupt packet, I tried to modify part of crc check
>>
>> I guess if the crc of received packet doesn't match with original
>> one, receiver would discard the packet.
>>
>> However, I found receiver accepts every packet even if crc check
>> returns 'false'.
>> (I expected receiver accepts packet only pass crc check by 'true')
>>
>> Why it always return false and how can I corrupt packet with
>> other ways ?
>>
>>
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