哈Ha
在关于SDR的系列的“周年”部分中，我想谈一谈其中的一种协议，这要感谢许多火腿“无意间”加入了数字宽带信号的世界。 该标准也是首次（据我们所知，也是唯一的）尝试以短波长传输数字声音的尝试。
正如许多人已经猜到的那样，我们将讨论DRM标准
-Digital Radio Mondiale （不要与其他DRM，数字版权管理相混淆）。
好吧，因为 如果我们谈论的是SDR，那么我们不仅会看到如何接收DRM，而且还会看到如何传输它。 继续下割。
故事
DRM标准的历史并不容易。 它于2003年首次推出，自2007年以来就进行了测试传输，并取得了不同程度的成功，而且仍在不断地持续进行。
DRM基于两个主要思想。
- 声音以6到34Kbit / s的比特率在短波长下以“数字质量”传输，没有噪声和衰减。 但是，此处的“数字质量”只能用引号引起来，因为 在12Kbit比特率下，声音来自相当低的质量。 另外，HF信号确实会受到噪声和衰落的影响，并且为了对“数字”进行解码，需要非常高的信噪比-这样普通的模拟信号听起来会更好。 通常，在现实生活中至少尝试一次接受DRM就足够了，以了解这种想法不会成功。 但是尽管如此，广播还是定期进行的，包括从俄罗斯（见KDPV）进行的广播，有些广播电台有时仍以DRM广播。
- FM波段中的声音传输。 该标准被称为DRM +。 这里的想法是节省频率资源-借助数字压缩，在100KHz频段中，您可以立即传输多达4种音频传输，这在诸如伦敦这样的大城市中已经有了不错的优势，因为那里不再有免费的频率。 另一方面，DAB已经在欧洲工作，这里根本不需要其他标准。 根据Wikipedia的说法，DRM +的测试广播是在2010年在苏格兰进行的，到目前为止，我还没有听说过广播DRM +的真实案例。
DRM标准从本质上来说是超现实的-广播电台已经运营了许多年，广播也在广播……但是，该标准没有接收器在出售。 一般而言。 没有 显然，由于该标准是数字的，所以通常的接收器只能听到嘶嘶声，而且还没有人学会如何用耳朵解码QAM。 因此，DRM的接收仅是业余无线电的娱乐。 似乎确实存在1-2个接收器，关于youtube上甚至还有几个视频（
1和
2 ），但是Ebay或Amazon上现在没有任何销售。
接收DRM的第二个问题是，在HF广播的城市中实际上已经死了-家用设备和电源的干扰很大，即使打开HF无线电，您也会听到一个pop啪声和噪音-在这种情况下解码不起作用在最佳情况下，接收机将能够显示屏幕保护站，但没有声音。 当然，您可以将天线放在阳台或屋顶上，进行仔细配置，原则上，从业余无线电爱好者的城市公寓接收和解码DRM很有可能。 普通人不会为这100％烦恼，没有人会爬上屋顶来悬挂天线来接收比特率为12Kbit / s的音频信号。
通常，没有接收者，没有观众。 但是有广播。 电影中的地鼠正在休息...
顺便说一下，目前，在撰写本文时（2019年7月），DRM +测试广播正在圣彼得堡进行，因此希望
成为地鼠的人可以尝试接收信号（没有声音可听，没有接收器，甚至没有用于DRM +的软件SDR解码器）。 对于接收，您可以使用RTL-SDR，如果幸运的话，在FM波段中，您可以看到宽度约为100KHz的数字信号。 但是，如上所述，找不到适合他的解码器。
DRM接收
关于radioscanner的DRM火腿的第一份报告可以追溯到2008年。 在普通的家用（甚至业余）接收器上无法接收到宽度为10KHz的数字信号，因此，那些想要焊接转换器以将IF接收器输出到声卡的人。 在出现SDR并自行解决问题之后，您可以在接收器的能力范围内选择任何带宽（对于基于声卡的第一个SDR，通常为48KHz，绰绰有余）。 解码本身是使用非常方便且高质量的
Dream程序执行的。
如上所述，DRM电台非常定期地工作，并且在空中找到它们并不是那么困难。 例如，在
websdr上，这样的信号在频谱上很容易区分-如果在广播范围内可以看到10KHz数字信号，那就是它。 在撰写本文时，以15 MHz运行的电台的屏幕截图示例：
仅使用websdr对其进行解码将不起作用，在线接收器的带宽太小。 但是，任何人都可以收听DRM，可以从
此处下载真实录制的文件。 对于解码，您可以使用已经提到的Dream程序，可以
在radioscanner网站上找到具有所有必需DLL的工作版本。
如果我们谈论“铁”接收器，例如Gospell GR-216接收器，但它在eBay或Amazon上均未发布。
编辑：根据评论中的建议，该接收器现在在澳大利亚市场以商标Tecsun Q-3061出售。 发行价为500AUD，约合350美元。
那些想要自己托管DRM电台的人可以在
https://www.drm.org/what-can-i-hear/broadcast-schedule-2/上查看时间表。
DRM传输
现在，我们转而关注另一个有趣的问题-传输DRM信号的可能性（如果我没有记错的话，这是RuNet首次对此进行描述）。 这可以使用GNU Radio和
gr-drm模块来完成 。
从技术上讲，DRM使用QAM调制，并且具有相当多的比特率和带宽设置。 另外，不仅可以传输声音（单声道和立体声），而且还可以传输文本，频道徽标和其他服务信息。 对于HF（AD模式），占用的频带可以在4.5到20KHz之间变化，但是实际上，仅遇到10KHz信号。 如前所述，对于VHF（模式E），使用100KHz频段。
表格来自
www.drm.org/DRM_Handbook_2018.pdf ：
该标准的更详细说明
位于PDF中 ，您可以在
Signalwiki上简要
阅读 。
让我们回到连接图。 如您所见，DRM编码器从多个组件生成信号。
- 快速访问通道（FAC）。 包含有关ODFM信号属性和SDC / MSC配置的信息。 频道信息每0.4s发送一次，这使接收器可以快速开始接收电台信号。 可以在DRM Configuration块中配置信号参数。
- 服务描述频道（SDC）。 描述MSC传输通道。
- 主要服务频道（MSC）。 包含数据帧； QAM16或QAM64可用于传输。
好吧，最有趣的是，所有这些操作都可以在常规PC上毫无问题地运行。 Gr-drm包含在Windows的PothosSDR软件包中，但是，,，它在那里不起作用-有信号，但是解码时会出错。 在Ubuntu下，一切都可以正常启动。
您可以将WAV文件或完整的SDR收发器（例如HackRF）用作GNU Radio中的输出设备。 对于那些想自己尝试的人，GRC文件位于破坏者下方。
rdm_transmit.grc<?xml version='1.0' encoding='utf-8'?> <?grc format='1' created='3.7.11'?> <flow_graph> <timestamp>Tue Apr 29 11:37:08 2014</timestamp> <block> <key>options</key> <param> <key>author</key> <value>Felix Wunsch</value> </param> <param> <key>window_size</key> <value>3000, 2000</value> </param> <param> <key>category</key> <value>Custom</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>description</key> <value>Generic DRM Transmitter. For the MSC, only SM and EEP is implemented.</value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(1016, 16)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>generate_options</key> <value>no_gui</value> </param> <param> <key>hier_block_src_path</key> <value>.:</value> </param> <param> <key>id</key> <value>drm_transmitter</value> </param> <param> <key>max_nouts</key> <value>0</value> </param> <param> <key>qt_qss_theme</key> <value></value> </param> <param> <key>realtime_scheduling</key> <value></value> </param> <param> <key>run_command</key> <value>{python} -u {filename}</value> </param> <param> <key>run_options</key> <value>run</value> </param> <param> <key>run</key> <value>True</value> </param> <param> <key>thread_safe_setters</key> <value></value> </param> <param> <key>title</key> <value>DRM Transmitter</value> </param> </block> <block> <key>variable</key> <param> <key>comment</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(240, 60)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>file_dest</value> </param> <param> <key>value</key> <value>"D:\\MyProjects\\GNURadio\\gr-drm-master\\apps\\sound_drm_out.wav"</value> </param> </block> <block> <key>variable</key> <param> <key>comment</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(56, 60)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>file_source</value> </param> <param> <key>value</key> <value>"D:\\MyProjects\\GNURadio\\gr-drm-master\\apps\\sound.wav"</value> </param> </block> <block> <key>variable_drm_config</key> <param> <key>audio_sample_rate</key> <value>12000</value> </param> <param> <key>comment</key> <value>Before generating the flow graph, define the path to a 24 kHz wav-file and change the parameters of the UHD sink. Do not forget to set the correct audio_sample_rate.</value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>_coordinate</key> <value>(1208, 12)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>tp</value> </param> <param> <key>long_interl</key> <value>True</value> </param> <param> <key>msc_mapping</key> <value>2</value> </param> <param> <key>msc_prot_level_2_16</key> <value>1</value> </param> <param> <key>msc_prot_level_2_64</key> <value>0</value> </param> <param> <key>RM</key> <value>1</value> </param> <param> <key>sdc_mapping</key> <value>0</value> </param> <param> <key>SO</key> <value>3</value> </param> <param> <key>station_label</key> <value>"Radioscanner Test"</value> </param> <param> <key>text_message</key> <value>"DRM transmission with GNU Radio"</value> </param> </block> <block> <key>analog_sig_source_x</key> <param> <key>amp</key> <value>1</value> </param> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>freq</key> <value>7000</value> </param> <param> <key>_coordinate</key> <value>(576, 624)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>analog_sig_source_x_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>offset</key> <value>0</value> </param> <param> <key>type</key> <value>complex</value> </param> <param> <key>samp_rate</key> <value>drm.FS_SOUNDCARD</value> </param> <param> <key>waveform</key> <value>analog.GR_COS_WAVE</value> </param> </block> <block> <key>audio_sink</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>device_name</key> <value></value> </param> <param> <key>_enabled</key> <value>0</value> </param> <param> <key>_coordinate</key> <value>(1184, 556)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>audio_sink_0</value> </param> <param> <key>num_inputs</key> <value>1</value> </param> <param> <key>ok_to_block</key> <value>True</value> </param> <param> <key>samp_rate</key> <value>48000</value> </param> </block> <block> <key>audio_source</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>device_name</key> <value></value> </param> <param> <key>_enabled</key> <value>0</value> </param> <param> <key>_coordinate</key> <value>(56, 156)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>audio_source_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>num_outputs</key> <value>1</value> </param> <param> <key>ok_to_block</key> <value>True</value> </param> <param> <key>samp_rate</key> <value>44100</value> </param> </block> <block> <key>blocks_complex_to_real</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>_coordinate</key> <value>(1008, 640)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_complex_to_real_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>vlen</key> <value>1</value> </param> </block> <block> <key>blocks_multiply_const_vxx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>const</key> <value>32768</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>_coordinate</key> <value>(272, 236)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_multiply_const_vxx_0</value> </param> <param> <key>type</key> <value>float</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>vlen</key> <value>1</value> </param> </block> <block> <key>blocks_multiply_const_vxx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value>Prevent clipping</value> </param> <param> <key>const</key> <value>7e-3</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(688, 468)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_multiply_const_vxx_1</value> </param> <param> <key>type</key> <value>complex</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>vlen</key> <value>1</value> </param> </block> <block> <key>blocks_multiply_xx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>_coordinate</key> <value>(864, 624)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_multiply_xx_0</value> </param> <param> <key>type</key> <value>complex</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>num_inputs</key> <value>2</value> </param> <param> <key>vlen</key> <value>1</value> </param> </block> <block> <key>blocks_wavfile_sink</key> <param> <key>bits_per_sample</key> <value>16</value> </param> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>file</key> <value>file_dest</value> </param> <param> <key>_coordinate</key> <value>(1200, 620)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_wavfile_sink_0</value> </param> <param> <key>nchan</key> <value>1</value> </param> <param> <key>samp_rate</key> <value>drm.FS_SOUNDCARD</value> </param> </block> <block> <key>blocks_wavfile_source</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>1</value> </param> <param> <key>file</key> <value>file_source</value> </param> <param> <key>_coordinate</key> <value>(56, 228)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>blocks_wavfile_source_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>nchan</key> <value>1</value> </param> <param> <key>repeat</key> <value>False</value> </param> </block> <block> <key>cell_mapping_cc</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value>Multiplex the three logical channels and the pilot cells and create transmission frames.</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(1184, 264)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>cell_mapping_cc_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>digital_ofdm_cyclic_prefixer</key> <param> <key>alias</key> <value></value> </param> <param> <key>cp_len</key> <value>tp.ofdm().nfft()*tp.ofdm().cp_ratio_enum()/tp.ofdm().cp_ratio_denom()</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>input_size</key> <value>tp.ofdm().nfft()</value> </param> <param> <key>_coordinate</key> <value>(456, 448)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>digital_ofdm_cyclic_prefixer_1</value> </param> <param> <key>tagname</key> <value></value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>rolloff</key> <value>0</value> </param> </block> <block> <key>drm_audio_encoder_sb</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(456, 240)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_audio_encoder_sb_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>len_out</key> <value>tp.msc().L_MUX()</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>drm_generate_fac_b</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(56, 344)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_generate_fac_b_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>drm_generate_sdc_b</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(56, 296)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_generate_sdc_b_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>drm_interleaver_cc</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value>Additional interleaving</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(952, 240)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_interleaver_cc_0</value> </param> <param> <key>depth</key> <value>drm.INTL_DEPTH_DRM</value> </param> <param> <key>interl_seq</key> <value>tp.msc().cell_interl_seq()</value> </param> <param> <key>long_interl</key> <value>tp.cfg().long_interl()</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> </block> <block> <key>drm_scrambler_bb</key> <param> <key>alias</key> <value></value> </param> <param> <key>block_len</key> <value>tp.msc().L_MUX()</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(608, 240)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_scrambler_bb_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> </block> <block> <key>drm_scrambler_bb</key> <param> <key>alias</key> <value></value> </param> <param> <key>block_len</key> <value>tp.fac().L()</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(608, 344)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_scrambler_bb_0_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> </block> <block> <key>drm_scrambler_bb</key> <param> <key>alias</key> <value></value> </param> <param> <key>block_len</key> <value>tp.sdc().L()</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(608, 296)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>drm_scrambler_bb_0_1</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> </block> <block> <key>fft_vxx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>fft_size</key> <value>tp.ofdm().nfft()</value> </param> <param> <key>forward</key> <value>False</value> </param> <param> <key>_coordinate</key> <value>(232, 440)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>fft_vxx_0</value> </param> <param> <key>type</key> <value>complex</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>nthreads</key> <value>1</value> </param> <param> <key>shift</key> <value>True</value> </param> <param> <key>window</key> <value></value> </param> </block> <block> <key>mlc_bc</key> <param> <key>alias</key> <value></value> </param> <param> <key>channel_type</key> <value>"FAC"</value> </param> <param> <key>comment</key> <value>Apply channel coding and interleaving</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(744, 340)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>mlc_bc_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>mlc_bc</key> <param> <key>alias</key> <value></value> </param> <param> <key>channel_type</key> <value>"MSC"</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(744, 236)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>mlc_bc_0_0</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>mlc_bc</key> <param> <key>alias</key> <value></value> </param> <param> <key>channel_type</key> <value>"SDC"</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(744, 292)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>mlc_bc_0_1</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>tp</key> <value>tp</value> </param> </block> <block> <key>rational_resampler_xxx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value>Ingoing sample rate is assumed to be 48 kHz. 250 kHz is one of the lowest achievable rates of the USRP.</value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>decim</key> <value>drm.FS_SOUNDCARD / 1000</value> </param> <param> <key>_enabled</key> <value>0</value> </param> <param> <key>fbw</key> <value>0</value> </param> <param> <key>_coordinate</key> <value>(864, 448)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>rational_resampler_xxx_0</value> </param> <param> <key>interp</key> <value>250</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>taps</key> <value></value> </param> <param> <key>type</key> <value>ccc</value> </param> </block> <block> <key>rational_resampler_xxx</key> <param> <key>alias</key> <value></value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>decim</key> <value>441</value> </param> <param> <key>_enabled</key> <value>0</value> </param> <param> <key>fbw</key> <value>0</value> </param> <param> <key>_coordinate</key> <value>(248, 136)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>rational_resampler_xxx_0_0</value> </param> <param> <key>interp</key> <value>240</value> </param> <param> <key>maxoutbuf</key> <value>0</value> </param> <param> <key>minoutbuf</key> <value>0</value> </param> <param> <key>taps</key> <value></value> </param> <param> <key>type</key> <value>fff</value> </param> </block> <block> <key>virtual_source</key> <param> <key>comment</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(56, 468)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>sym_in</value> </param> <param> <key>stream_id</key> <value>symbols</value> </param> </block> <block> <key>virtual_sink</key> <param> <key>comment</key> <value></value> </param> <param> <key>_enabled</key> <value>True</value> </param> <param> <key>_coordinate</key> <value>(1408, 292)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>sym_out</value> </param> <param> <key>stream_id</key> <value>symbols</value> </param> </block> <block> <key>uhd_usrp_sink</key> <param> <key>alias</key> <value></value> </param> <param> <key>ant0</key> <value>TXA</value> </param> <param> <key>bw0</key> <value>0</value> </param> <param> <key>center_freq0</key> <value>5e6</value> </param> <param> <key>norm_gain0</key> <value>False</value> </param> <param> <key>gain0</key> <value>0</value> </param> <param> <key>ant10</key> <value></value> </param> <param> <key>bw10</key> <value>0</value> </param> <param> <key>center_freq10</key> <value>0</value> </param> <param> <key>norm_gain10</key> <value>False</value> </param> <param> <key>gain10</key> <value>0</value> </param> <param> <key>ant11</key> <value></value> </param> <param> <key>bw11</key> <value>0</value> </param> <param> <key>center_freq11</key> <value>0</value> </param> <param> <key>norm_gain11</key> <value>False</value> </param> <param> <key>gain11</key> <value>0</value> </param> <param> <key>ant12</key> <value></value> </param> <param> <key>bw12</key> <value>0</value> </param> <param> <key>center_freq12</key> <value>0</value> </param> <param> <key>norm_gain12</key> <value>False</value> </param> <param> <key>gain12</key> <value>0</value> </param> <param> <key>ant13</key> <value></value> </param> <param> <key>bw13</key> <value>0</value> </param> <param> <key>center_freq13</key> <value>0</value> </param> <param> <key>norm_gain13</key> <value>False</value> </param> <param> <key>gain13</key> <value>0</value> </param> <param> <key>ant14</key> <value></value> </param> <param> <key>bw14</key> <value>0</value> </param> <param> <key>center_freq14</key> <value>0</value> </param> <param> <key>norm_gain14</key> <value>False</value> </param> <param> <key>gain14</key> <value>0</value> </param> <param> <key>ant15</key> <value></value> </param> <param> <key>bw15</key> <value>0</value> </param> <param> <key>center_freq15</key> <value>0</value> </param> <param> <key>norm_gain15</key> <value>False</value> </param> <param> <key>gain15</key> <value>0</value> </param> <param> <key>ant16</key> <value></value> </param> <param> <key>bw16</key> <value>0</value> </param> <param> <key>center_freq16</key> <value>0</value> </param> <param> <key>norm_gain16</key> <value>False</value> </param> <param> <key>gain16</key> <value>0</value> </param> <param> <key>ant17</key> <value></value> </param> <param> <key>bw17</key> <value>0</value> </param> <param> <key>center_freq17</key> <value>0</value> </param> <param> <key>norm_gain17</key> <value>False</value> </param> <param> <key>gain17</key> <value>0</value> </param> <param> <key>ant18</key> <value></value> </param> <param> <key>bw18</key> <value>0</value> </param> <param> <key>center_freq18</key> <value>0</value> </param> <param> <key>norm_gain18</key> <value>False</value> </param> <param> <key>gain18</key> <value>0</value> </param> <param> <key>ant19</key> <value></value> </param> <param> <key>bw19</key> <value>0</value> </param> <param> <key>center_freq19</key> <value>0</value> </param> <param> <key>norm_gain19</key> <value>False</value> </param> <param> <key>gain19</key> <value>0</value> </param> <param> <key>ant1</key> <value></value> </param> <param> <key>bw1</key> <value>0</value> </param> <param> <key>center_freq1</key> <value>0</value> </param> <param> <key>norm_gain1</key> <value>False</value> </param> <param> <key>gain1</key> <value>0</value> </param> <param> <key>ant20</key> <value></value> </param> <param> <key>bw20</key> <value>0</value> </param> <param> <key>center_freq20</key> <value>0</value> </param> <param> <key>norm_gain20</key> <value>False</value> </param> <param> <key>gain20</key> <value>0</value> </param> <param> <key>ant21</key> <value></value> </param> <param> <key>bw21</key> <value>0</value> </param> <param> <key>center_freq21</key> <value>0</value> </param> <param> <key>norm_gain21</key> <value>False</value> </param> <param> <key>gain21</key> <value>0</value> </param> <param> <key>ant22</key> <value></value> </param> <param> <key>bw22</key> <value>0</value> </param> <param> <key>center_freq22</key> <value>0</value> </param> <param> <key>norm_gain22</key> <value>False</value> </param> <param> <key>gain22</key> <value>0</value> </param> <param> <key>ant23</key> <value></value> </param> <param> <key>bw23</key> <value>0</value> </param> <param> <key>center_freq23</key> <value>0</value> </param> <param> <key>norm_gain23</key> <value>False</value> </param> <param> <key>gain23</key> <value>0</value> </param> <param> <key>ant24</key> <value></value> </param> <param> <key>bw24</key> <value>0</value> </param> <param> <key>center_freq24</key> <value>0</value> </param> <param> <key>norm_gain24</key> <value>False</value> </param> <param> <key>gain24</key> <value>0</value> </param> <param> <key>ant25</key> <value></value> </param> <param> <key>bw25</key> <value>0</value> </param> <param> <key>center_freq25</key> <value>0</value> </param> <param> <key>norm_gain25</key> <value>False</value> </param> <param> <key>gain25</key> <value>0</value> </param> <param> <key>ant26</key> <value></value> </param> <param> <key>bw26</key> <value>0</value> </param> <param> <key>center_freq26</key> <value>0</value> </param> <param> <key>norm_gain26</key> <value>False</value> </param> <param> <key>gain26</key> <value>0</value> </param> <param> <key>ant27</key> <value></value> </param> <param> <key>bw27</key> <value>0</value> </param> <param> <key>center_freq27</key> <value>0</value> </param> <param> <key>norm_gain27</key> <value>False</value> </param> <param> <key>gain27</key> <value>0</value> </param> <param> <key>ant28</key> <value></value> </param> <param> <key>bw28</key> <value>0</value> </param> <param> <key>center_freq28</key> <value>0</value> </param> <param> <key>norm_gain28</key> <value>False</value> </param> <param> <key>gain28</key> <value>0</value> </param> <param> <key>ant29</key> <value></value> </param> <param> <key>bw29</key> <value>0</value> </param> <param> <key>center_freq29</key> <value>0</value> </param> <param> <key>norm_gain29</key> <value>False</value> </param> <param> <key>gain29</key> <value>0</value> </param> <param> <key>ant2</key> <value></value> </param> <param> <key>bw2</key> <value>0</value> </param> <param> <key>center_freq2</key> <value>0</value> </param> <param> <key>norm_gain2</key> <value>False</value> </param> <param> <key>gain2</key> <value>0</value> </param> <param> <key>ant30</key> <value></value> </param> <param> <key>bw30</key> <value>0</value> </param> <param> <key>center_freq30</key> <value>0</value> </param> <param> <key>norm_gain30</key> <value>False</value> </param> <param> <key>gain30</key> <value>0</value> </param> <param> <key>ant31</key> <value></value> </param> <param> <key>bw31</key> <value>0</value> </param> <param> <key>center_freq31</key> <value>0</value> </param> <param> <key>norm_gain31</key> <value>False</value> </param> <param> <key>gain31</key> <value>0</value> </param> <param> <key>ant3</key> <value></value> </param> <param> <key>bw3</key> <value>0</value> </param> <param> <key>center_freq3</key> <value>0</value> </param> <param> <key>norm_gain3</key> <value>False</value> </param> <param> <key>gain3</key> <value>0</value> </param> <param> <key>ant4</key> <value></value> </param> <param> <key>bw4</key> <value>0</value> </param> <param> <key>center_freq4</key> <value>0</value> </param> <param> <key>norm_gain4</key> <value>False</value> </param> <param> <key>gain4</key> <value>0</value> </param> <param> <key>ant5</key> <value></value> </param> <param> <key>bw5</key> <value>0</value> </param> <param> <key>center_freq5</key> <value>0</value> </param> <param> <key>norm_gain5</key> <value>False</value> </param> <param> <key>gain5</key> <value>0</value> </param> <param> <key>ant6</key> <value></value> </param> <param> <key>bw6</key> <value>0</value> </param> <param> <key>center_freq6</key> <value>0</value> </param> <param> <key>norm_gain6</key> <value>False</value> </param> <param> <key>gain6</key> <value>0</value> </param> <param> <key>ant7</key> <value></value> </param> <param> <key>bw7</key> <value>0</value> </param> <param> <key>center_freq7</key> <value>0</value> </param> <param> <key>norm_gain7</key> <value>False</value> </param> <param> <key>gain7</key> <value>0</value> </param> <param> <key>ant8</key> <value></value> </param> <param> <key>bw8</key> <value>0</value> </param> <param> <key>center_freq8</key> <value>0</value> </param> <param> <key>norm_gain8</key> <value>False</value> </param> <param> <key>gain8</key> <value>0</value> </param> <param> <key>ant9</key> <value></value> </param> <param> <key>bw9</key> <value>0</value> </param> <param> <key>center_freq9</key> <value>0</value> </param> <param> <key>norm_gain9</key> <value>False</value> </param> <param> <key>gain9</key> <value>0</value> </param> <param> <key>clock_rate</key> <value>0.0</value> </param> <param> <key>comment</key> <value></value> </param> <param> <key>affinity</key> <value></value> </param> <param> <key>dev_addr</key> <value></value> </param> <param> <key>dev_args</key> <value>""</value> </param> <param> <key>_enabled</key> <value>0</value> </param> <param> <key>_coordinate</key> <value>(1168, 424)</value> </param> <param> <key>_rotation</key> <value>0</value> </param> <param> <key>id</key> <value>uhd_usrp_sink_0</value> </param> <param> <key>type</key> <value>fc32</value> </param> <param> <key>clock_source0</key> <value></value> </param> <param> <key>sd_spec0</key> <value></value> </param> <param> <key>time_source0</key> <value></value> </param> <param> <key>clock_source1</key> <value></value> </param> <param> <key>sd_spec1</key> <value></value> </param> <param> <key>time_source1</key> <value></value> </param> <param> <key>clock_source2</key> <value></value> </param> <param> <key>sd_spec2</key> <value></value> </param> <param> <key>time_source2</key> <value></value> </param> <param> <key>clock_source3</key> <value></value> </param> <param> <key>sd_spec3</key> <value></value> </param> <param> <key>time_source3</key> <value></value> </param> <param> <key>clock_source4</key> <value></value> </param> <param> <key>sd_spec4</key> <value></value> </param> <param> <key>time_source4</key> <value></value> </param> <param> <key>clock_source5</key> <value></value> </param> <param> <key>sd_spec5</key> <value></value> </param> <param> <key>time_source5</key> <value></value> </param> <param> <key>clock_source6</key> <value></value> </param> <param> <key>sd_spec6</key> <value></value> </param> <param> <key>time_source6</key> <value></value> </param> <param> <key>clock_source7</key> <value></value> </param> <param> <key>sd_spec7</key> <value></value> </param> <param> <key>time_source7</key> <value></value> </param> <param> <key>nchan</key> <value>1</value> </param> <param> <key>num_mboards</key> <value>1</value> </param> <param> <key>samp_rate</key> <value>48000 * 250 / 48</value> </param> <param> <key>hide_cmd_port</key> <value>False</value> </param> <param> <key>hide_lo_controls</key> <value>True</value> </param> <param> <key>stream_args</key> <value></value> </param> <param> <key>stream_chans</key> <value>[]</value> </param> <param> <key>sync</key> <value></value> </param> <param> <key>len_tag_name</key> <value></value> </param> <param> <key>otw</key> <value></value> </param> </block> <connection> <source_block_id>analog_sig_source_x_0</source_block_id> <sink_block_id>blocks_multiply_xx_0</sink_block_id> <source_key>0</source_key> <sink_key>1</sink_key> </connection> <connection> <source_block_id>audio_source_0</source_block_id> <sink_block_id>rational_resampler_xxx_0_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_complex_to_real_0</source_block_id> <sink_block_id>audio_sink_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_complex_to_real_0</source_block_id> <sink_block_id>blocks_wavfile_sink_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_multiply_const_vxx_0</source_block_id> <sink_block_id>drm_audio_encoder_sb_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_multiply_const_vxx_1</source_block_id> <sink_block_id>blocks_multiply_xx_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_multiply_const_vxx_1</source_block_id> <sink_block_id>rational_resampler_xxx_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_multiply_xx_0</source_block_id> <sink_block_id>blocks_complex_to_real_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>blocks_wavfile_source_0</source_block_id> <sink_block_id>blocks_multiply_const_vxx_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>cell_mapping_cc_0</source_block_id> <sink_block_id>sym_out</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>digital_ofdm_cyclic_prefixer_1</source_block_id> <sink_block_id>blocks_multiply_const_vxx_1</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_audio_encoder_sb_0</source_block_id> <sink_block_id>drm_scrambler_bb_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_generate_fac_b_0</source_block_id> <sink_block_id>drm_scrambler_bb_0_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_generate_sdc_b_0</source_block_id> <sink_block_id>drm_scrambler_bb_0_1</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_interleaver_cc_0</source_block_id> <sink_block_id>cell_mapping_cc_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_scrambler_bb_0</source_block_id> <sink_block_id>mlc_bc_0_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_scrambler_bb_0_0</source_block_id> <sink_block_id>mlc_bc_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>drm_scrambler_bb_0_1</source_block_id> <sink_block_id>mlc_bc_0_1</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>fft_vxx_0</source_block_id> <sink_block_id>digital_ofdm_cyclic_prefixer_1</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>mlc_bc_0</source_block_id> <sink_block_id>cell_mapping_cc_0</sink_block_id> <source_key>0</source_key> <sink_key>2</sink_key> </connection> <connection> <source_block_id>mlc_bc_0_0</source_block_id> <sink_block_id>drm_interleaver_cc_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>mlc_bc_0_1</source_block_id> <sink_block_id>cell_mapping_cc_0</sink_block_id> <source_key>0</source_key> <sink_key>1</sink_key> </connection> <connection> <source_block_id>rational_resampler_xxx_0</source_block_id> <sink_block_id>uhd_usrp_sink_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>rational_resampler_xxx_0_0</source_block_id> <sink_block_id>drm_audio_encoder_sb_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> <connection> <source_block_id>sym_in</source_block_id> <sink_block_id>fft_vxx_0</sink_block_id> <source_key>0</source_key> <sink_key>0</sink_key> </connection> </flow_graph>
US，USRP不会传输到HF，但是我没有HackRF。 因此，不可能进行真正的广播测试，但是我可以确认通过Dream进行的声音解码没有错误。
结论
奇怪的是，尽管看似99％的绝望，但DRM标准仍然有效。 但是，他不太可能成功并超越任何本地实验-DRM中的声音质量不再符合现代标准，并且市场上没有接收器。 从技术角度来看，2003年似乎没有“突破”的意义已不复存在。
但是另一方面，DRM标准包含许多有趣的想法，对于无线电爱好者来说，它的接收是（现在）非常有趣的体验，任何可以在drm电台播出时加入它的人都可以。
至此，关于SDR的系列文章结束了，我希望有人对此感兴趣并且有用。
所有成功的实验。