> {quote：title = SpontaneousOrder写道：} {quote}> 1. MXA / PXA指定二阶谐波失真，但二阶IMD f~1~ + f~2~？
> 2.信号链的哪一部分对二阶IMD贡献最大，包括f~1~ + f~2~，2f~1~和2f~2~？
它是混频器，IF放大器，ADC还是其他什么？
1）我没有看到它的规格但你可能会认为双音SOI比SHI差6 dB左右，相同的输入信号（相同功率的两个音调相对于谐波的一个音调）SOI有6 dB
更高的峰值功率。
但！
在具有预选器的带的部分中，SOI和SHI将非常高，因为调谐到二次谐波的预选器将基极与混频器隔离。
在PXA中，当二阶信号约为3.6GHz（基频高于1.8GHz）时，会发生这种情况。
2）通常它是第一个混频器，原因是高频率和低频率组件可以更容易地优化以获得更好的性能，但在PXA中，IF被优化以实际改善原始混频器响应，因此它是整个链
贡献。
以上来自于谷歌翻译
以下为原文
> {quote:title=SpontaneousOrder wrote:}{quote}
> 1. MXA/PXA specifies the 2nd order harmonics distortion, but what about the 2nd order IMD f ~1~ + f ~2~ ?
> 2. Which part of the signal chain contribute the most to the 2nd order IMDs, including f ~1~ + f ~2~, 2f ~1~ and 2f ~2~ ? Is it the mixer, the IF amplifier, the ADC or something else?
1) I've not seen it spec but you might expect two-tone SOI to be about 6 dB worse than SHI as for the same input signal (two tones at the same power relative to one tone for harmonics) the SOI has 6 dB higher peak power. BUT! in the portion of the band with a pre-selector, the SOI and SHI will be very high as the preselector tuned to the second harmonic will isolate the fundamental from the mixer. In PXA this occurs when the second order signal is about 3.6 GHz (fundamental above 1.8 GHz).
2)Usually it is the first mixer, the reason being it is high frequency and lower freq components can be more readily optimized for better peformance, but in the PXA the IF is optimized to actually improve the raw mixer response so it is the whole chain that contributes.
> {quote：title = SpontaneousOrder写道：} {quote}> 1. MXA / PXA指定二阶谐波失真，但二阶IMD f~1~ + f~2~？
> 2.信号链的哪一部分对二阶IMD贡献最大，包括f~1~ + f~2~，2f~1~和2f~2~？
它是混频器，IF放大器，ADC还是其他什么？
1）我没有看到它的规格但你可能会认为双音SOI比SHI差6 dB左右，相同的输入信号（相同功率的两个音调相对于谐波的一个音调）SOI有6 dB
更高的峰值功率。
但！
在具有预选器的带的部分中，SOI和SHI将非常高，因为调谐到二次谐波的预选器将基极与混频器隔离。
在PXA中，当二阶信号约为3.6GHz（基频高于1.8GHz）时，会发生这种情况。
2）通常它是第一个混频器，原因是高频率和低频率组件可以更容易地优化以获得更好的性能，但在PXA中，IF被优化以实际改善原始混频器响应，因此它是整个链
贡献。
以上来自于谷歌翻译
以下为原文
> {quote:title=SpontaneousOrder wrote:}{quote}
> 1. MXA/PXA specifies the 2nd order harmonics distortion, but what about the 2nd order IMD f ~1~ + f ~2~ ?
> 2. Which part of the signal chain contribute the most to the 2nd order IMDs, including f ~1~ + f ~2~, 2f ~1~ and 2f ~2~ ? Is it the mixer, the IF amplifier, the ADC or something else?
1) I've not seen it spec but you might expect two-tone SOI to be about 6 dB worse than SHI as for the same input signal (two tones at the same power relative to one tone for harmonics) the SOI has 6 dB higher peak power. BUT! in the portion of the band with a pre-selector, the SOI and SHI will be very high as the preselector tuned to the second harmonic will isolate the fundamental from the mixer. In PXA this occurs when the second order signal is about 3.6 GHz (fundamental above 1.8 GHz).
2)Usually it is the first mixer, the reason being it is high frequency and lower freq components can be more readily optimized for better peformance, but in the PXA the IF is optimized to actually improve the raw mixer response so it is the whole chain that contributes.
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