GnuRadio 上的 GMSK 传输问题答案

【问题标题】：GMSK transmission issues on GnuRadioGnuRadio 上的 GMSK 传输问题
【发布时间】：2020-02-07 21:38:54
【问题描述】：

我正在尝试实施相当简单的方案，将数据从一个 sdr 板传输到另一个板。我正在使用 GnuRadio 3.7.14，我的同伴方案看起来像这样

源文件是一个 96 字节长的二进制文件，看起来像这样

00000000  00 00 00 ff aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00000010  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00000020  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00000030  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00000040  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000060

在输出时，我希望在一些噪音之后会重复输入模式（可能有一些错误），但实际上它看起来像这样

00004610  00 00 00 1f f5 55 55 55  55 55 55 55 55 55 55 55  |.....UUUUUUUUUUU|
00004620  55 55 55 55 55 55 55 55  53 63 eb ea aa a8 aa aa  |UUUUUUUUSc......|
00004630  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004640  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004650  80 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004660  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 88  |................|
00004670  80 00 00 7f d5 55 55 55  55 55 55 55 55 55 55 55  |.....UUUUUUUUUUU|
00004680  55 55 55 55 55 55 55 0d  0b a2 aa aa aa aa aa aa  |UUUUUUU.........|
00004690  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
000046a0  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
000046b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000046c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000046d0  00 00 01 ff 55 55 55 55  55 55 55 55 55 55 55 51  |....UUUUUUUUUUUQ|
000046e0  15 61 55 31 75 fc aa aa  aa aa aa aa aa aa aa aa  |.aU1u...........|
000046f0  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004700  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa a8  |................|
00004710  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004720  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004730  00 00 03 fe aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004740  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004750  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004760  aa aa 9a ac 6e 8a db 59  3c ae aa b8 aa ac aa a8  |....n..Y<.......|
00004770  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004780  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004790  00 00 07 fd 55 55 55 55  55 55 55 55 55 55 55 55  |....UUUUUUUUUUUU|
000047a0  55 55 55 55 55 55 55 55  55 45 55 55 55 55 5b 55  |UUUUUUUUUEUUUU[U|
000047b0  28 aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |(...............|
000047c0  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa a0  |................|
000047d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000047e0  00 00 00 00 00 00 00 00  00 00 00 00 01 40 20 00  |.............@ .|
000047f0  00 00 1f f5 55 55 55 55  55 55 55 55 55 55 55 55  |....UUUUUUUUUUUU|
00004800  55 55 55 55 55 55 55 55  55 55 55 55 55 64 ab aa  |UUUUUUUUUUUUUd..|
00004810  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004820  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa 80  |................|
00004830  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004840  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004850  00 00 7f d5 55 55 55 55  55 55 55 55 55 55 55 55  |....UUUUUUUUUUUU|
00004860  55 55 55 55 55 55 55 6e  aa aa aa aa aa aa aa aa  |UUUUUUUn........|
00004870  aa aa aa aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
00004880  aa aa aa aa aa aa aa aa  aa aa aa a8 ab b3 54 00  |..............T.|
00004890  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000048a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000048b0  00 03 fe aa aa aa aa aa  aa aa aa aa aa aa aa aa  |................|
000048c0  aa aa aa aa aa aa a8 5d  15 55 55 55 55 55 55 55  |.......].UUUUUUU|
000048d0  55 55 55 55 55 55 55 55  55 55 55 55 55 55 55 55  |UUUUUUUUUUUUUUUU|
000048e0  55 55 55 55 55 55 55 55  55 55 41 56 b6 aa a0 00  |UUUUUUUUUUAV....|
000048f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00004900  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

我手动获取了这段输出文件，因此它与输入对齐。所以，在这里我看到了两个问题（我认为有一个原因）：

字节 0xAA (10101010b) 在消息的某些部分切换为 0x55(01010101b)，反之亦然
消息的开头“滑出”，字符串 47f0 和 4610 之间有 8 位差异

明显的原因是接收者获得的比特数量与发送者发送的不同，但我怀疑究竟是什么导致了这种行为？如何调试它以找出问题所在？

关于我的设置的几句话：我使用 3 个板，一个 USRP B210，一个 Limesdr-USB 和一个 Limesdr-Mini。我至少在 4 种不同的组合中尝试了这个实验，包括从电路板发送到自身，每次都收到相同的结果。板子好像没问题，他们成功接收调频广播并通过调频相互发送/接收声音。

谢谢！

【问题讨论】：

标签： gnuradio gnuradio-companion

【解决方案1】：

实际上我发现了类似的问题，那里给出的食谱也对我有用。 GFSK demodulation with Xlating filter in GNU Radio

【讨论】：