HF（0-30MHZ）直接采样模式
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Steve Markgraf of Osmocom has
created an experimental software and hardware modification to receive 0~30Mhz(*) by using the 28.8 MHz RTL2832U ADCs for RF sampling and aliasing to do the conversion.史蒂夫Osmocom马克格拉夫已经
创造了一个实验性的软件和硬件修改接收0〜30MHz的（*）使用28.8兆赫的RTL2832U的ADC，可用于射频采样和抗锯齿做转换。 In practice you only get DC-14.4MHz in the first Nyquist zone but the upper could be had by using a 14.4 MHz to 28.8 MHz bandpass filter.在实践中，你只能获得DC-14.4MHz第一奈奎斯特区域，但接收更高的频率使用14.4 MHz到28.8 MHz带通滤波器可以了。 In the stereotypical ezcap boards you can test this by connecting an appropriately long wire antenna to the right side of capacitor 17 (on EzTV668 1.1, at least) that goes to pin 1 of the RTL2832U.在的刻板ezcap板，你可以适当长的电线天线通过连接电容器C17的右侧（，至少上EzTV668 1.1）去针1 RTL2832U的测试。 That's the one by the dot on the chip surface.这是一个通过在芯片表面上的点。 Apparently even pressing a wet finger onto the capacitor can pick up strong AM stations.显然，即使按潮湿的手指上的电容可以拿起强AM广播电台。 This bypasses static protection among other things so there's a chance of destroying your dongle.绕过静态的保护，其中包括，所以这是一个机会，摧毁你的电视棒。 For gr-osmosdr the parameter direct_samp=1 or direct_samp=2 gives you the two I or two Q inputs.对于GR-osmosdr的参数direct_samp = 1或direct_samp = 2为您提供了两个I或两个Q输入。
Differential input差分输入 
Since then the direct sampling branch has been integrated into main and a number of people have also done balun stuff to use both RTL2832U ADC inputs (usually the two I) in direct sampling mode.
Dekar has a page showing how to use an ADSL transformer to generate signal for the ADCs differential input
using pin 1 (+I) and 2(-I) on the RTL2832.
mikig has a useful
pdf schematic with part numbers for using wide band transformers or toroids for winding your own.从那时起，直接采样分支已融入主，有不少人也做巴伦的东西同时使用RTL2832U的ADC输入直接采样模式（通常为两个I）。
Dekar有一个页面显示了如何使用ADSL变压器产生ADC的差分信号
输入引脚1（+ I）和2（I）RTL2832 mikig使用宽带变压器或环形缠绕自己的
PDF原理有一个有用的部分号码。 Here's a series of photos showing how to
use a FT37-43 ferrite core .这里有一个系列的照片展示了如何
使用FT37-43铁氧体磁芯 。 The ADC has a differential/balanced input so this is done mainly for the unbalanced->balanced conversion.该ADC具有差分/平衡输入，所以这是主要用于不平衡 - 平衡转换完成。 But the ADC input pins also have a DC offset so you can't just connect one to GND for that.但ADC输入引脚还具有直流偏移，因此，你不能只是连接到GND为。 Impedance matching can be done as well but the impedance isn't known.阻抗匹配可以做的很好，但的阻抗不知道。 ~200 Ohms seems reasonable and is mentioned in some of the tuner datasheets. 〜200欧姆似乎是合理的，在某些调谐器芯片的数据手册中提到。 4:1 baluns that are used for cable-tv might also work, depending on the impedance of your antenna. 4:1巴伦用于有线电视也可能正常工作，这取决于你的天线阻抗。
If you're particularly interested in HF work then an upconverter would be better than the HF mod.如果你特别感兴趣的HF工作再上变频器将优于HF国防部。 With the mod there will be aliases(*) for any frequency over 14.4 Mhz (1/2 the 28.8 clock rate).与国防部会有别名（*）对任何频率14.4兆赫（1/2的28.8时钟速率）。 And probably other little idiosyncracies.可能是其他小特点。 A lot of people chose to just use an upconverter instead.很多人选择，而不是只使用一个变频器。
KF7LE wrote up short summaries comparing 16 popular upconverters . KF7LE写了简短的总结，比较流行的上变频器16 。 [ 此帖被BG0APD在2013-05-07 01:28重新编辑 ]
