1 电磁波的波段命名 1）HF：0.003 to 0.03 GHz，High Frequency 2）VHF：0.03 to 0.3 GHz，Very High Frequency 3）UHF：0.3 to 1 GHz，Ultra High Frequency 4）L：1 to 2 GHz，Long wave 5）S：2 to 4 GHz，Short wave 6）C：4 to 8 GHz，S与X折中，妥协（Compromise） 7）X：8 to 12 GHz，火控雷达，X代表准心（Crosshair） 8）Ku：12 to 18 GHz，Kurz-under，表示短以下 9）K：18 to 27 GHz，Kurz，德语表示短 10）Ka：27 to 40 GHz，Kurz-above，表示短以上 11）mm or G：110 to 300 GHz，Millimeter，毫米波(实际上一般包含300毫米波) - 300 GHz） 2 天线 2.1 与漆包线相比，杜邦线 [19-Mar-2022] 杜邦线，即多股铜线，受潮效果小，高频信号响应更好。当然，如果有屏蔽线，那是最好的。 2.2天线设计软件 ANTENNA DESIGN PROGRAMS http://www.ve3sqb.com/ 2.3天线测试设备 驻波表 2.4计算天线参数 八木天线：主振子长度等于1/2波长。 2)拉杆天线:天线长度等于1/2波长。 3）GPS螺旋天线：螺旋直径等于1/2波长。 4）Wi-Fi偶极子天线：2.4GHz波长约为12.49 cm左右。偶极子的一半是向左突出的白线，而偶极子的另一半是金属柱。每一半与另一半电绝缘，长度约为1/4波长。类似的天线大约有2条dBi增益，并呈现相对圆形的辐射图案。 5）PIFA：手机天线，矩形辐射体PIFA天线长边和宽边的和谐相似Lambda / 4 3 收音机 3.1 AM重要元器件 AM中周中频是465KHz，DSP低中频是45KHz。 FM中周中频10.7MHz，DSP低中频是120KHz。 磁棒天线:单个漆包线绕组或多股线(杜邦线是多股线)绕组，次级圈数一般取初级圈数的1/10，多点少点。 双联电容器：将两个可变电容器的动片组装在同一转轴上，形成同轴可变电容器。两个可变电容器同轴链接，同步动作，称为双联可变电容，俗称双联电容。产生本振频率的双联电容器Fo，本振频率Fo比被接收信号更频繁Fs高一个中频Fo - Fs = 465KHz（overseas 455KHz）；另一个和中周一起用来确保差频等于465kHz。陶瓷滤波器取代了双联电容器。 中周：中周变压器或LC谐振也是一种电感器，所以它的符号也是L，带旋转磁芯的长方体铁壳用于调节其谐振频率，谐振频率为465KHz，谐振频率465KHz低于AM最低接收频率为535KHz。中频变压器还具有阻抗匹配功能，使各级电路处于最佳状态，保证了收音机的性能。超外差收音机一般有三个中周。当我还是个孩子的时候，我用螺丝刀调整了中周的可旋转磁芯，但我不知道组件叫中周。 DSP：类似于集成电路内部AM模拟收音机中周部件输出低中频信号45KHz被ADC数字化后，由DSP数字化处理。 zhihu: 这是什么电子元件，为什么现在的电子产品似乎看不到？ 3.2单片收音集成电路Single Chip Radio 无锡华润华晶微电子： CD1691/CD1191 Samsung: KA22426/KA22425 Silicon Labs: si4825 Sony: CXA1019 Toshiba: AM TA7641BP, 1980s; TA8127, 1990s; AM/FM single IC after 1987 3.3I2C接口收音集成电路 数字DSP集成在收音芯片中PLL，PLL产生本振频率Fo，通过I2C本振频率控制Fo比被接收信号的频率Fs高低中频。低中频的目的是减少ADC采样时的数据量。 3.4Head Unit CVR: Cockpit Voice Recorder is short for CVR, part number FA2100. TI DSP x 2, QuickLogic MCU, Intel SLC Nand Flash 宏光Mini：AU7860A 致胜CD机：NEC V850 70F3237M2GJA 4 RTL2832U 4.1 RTL2832U https://homepages.uni-regensburg.de/~erc24492/SDR/Data_rtl2832u.pdf The RTL2832U integrates CPU 8051. The RTL2832U supports tuners at IF (Intermediate Frequency, 36.125MHz), low-IF (4.57MHz), or Zero-IF output using a 28.8MHz crystal. Two USB endpoints: one control, one bulk Endpoint A for MPEG2-TS 188-byte packet including 4-byte header (1-byte Sync, 3-bit conf, 13-bit PID, 1-byte CC). The V4L/DVB kernel developer Antti Palosaari, who discovered an undocumented operation mode (SDR mode: disable page0 DAGC.bit5) for some USB DVB-T dongles based on the Realtek RTL2832U chipset, enabling them to be used as a cheap Software Defined Radio (SDR) front-end. The key feature is that the chip allows transferring raw I/Q samples to the host, which in principle is responsible for DAB/DVB /FM demodulation. Rafael Micro R820T2 is a non Zero-IF tuner IC. 4.2USB驱动安装工具Zadig Akeo Consulting is a small Software Development company, established in the North-West of Ireland, in the breathtaking wilderness of County Donegal. Zadig - USB driver installation made easy, based on Windows Driver Installer library (libwdi). https://zadig.akeo.ie/ 4.3 SDR-Sharp for Windows SDR# (aka “SDRSharp”) is an easy-to-use yet small and fast Software Defined Radio application for Windows created by Youssef Touil with collaborative assistance from other talented software engineers. SDR# is written in C#, a modern, general-purpose, object-oriented programming language developed by Microsoft. Download SDR-Sharp for Windows from airspy dot com. Run install-rtlsdr dot bat after uncompress the zip file. Because most of the RTL2832U devices are connected using USB, the librtlsdr library depends on the libusb library to communicate with the device. SDR-Sharp rtlsdr.dll libusb-1.0.dll WinUSB RTL2832U 4.4 HDSDR ExtIO_RTL2832.dll (Extended Input/Output) is a wrapper of librtlsdr. Latest version of librtlsdr and libusbx was used to make the dll. 5 osmo-fl2k After reverse-engineering the USB protocol of the FL2000 in 2016, Steve Markgraf discovered through experimentation that it is possible to operate the FL2000 in a way that both horizontal and vertical synchronization are disabled, thus creating a continous stream of samples. This work resulted in osmo-fl2k, which so far was used to transmit low-power FM, DAB, DVB-T, GSM, UMTS and GPS signals. VGA Red pin of 15 pins is connected to FM antenna. 6Abbreviations AF3371：AccFast，Acc表示Access CW：Continuous Wave，等幅电报通信 DX：Distant eXchange ESS ES8380：Electronic Speech ystems HAM：业余无线电，由三个人的姓的第一个字母组成 ICOM：Inoue Communication Electronics osmocom: Open Source MObile COMmunication for RTL SDR, founded by Steve Markgraf PIFA：Planar Inverted F-shaped Antenna SSB：Single Side Band