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Introduction to PIM Testing (1 人正在瀏覽) (1) 訪客
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主題: Introduction to PIM Testing
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mikechang (管理員)
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Introduction to PIM Testing 2 年, 7 個月 之前 聲譽: 0  
Heterodyning, or the mixing of two radio frequency signals to produce new signals, particularly one at the sum F1+F2 and the other at the difference F1-F2, has been known since the earliest years of the 20th century. Edwin Armstrong’s super heterodyne receiver, invented in 1918, mixed the received signal with a local oscillator to produce a constant intermediate frequency (IF) that can be processed more simply than the original carrier frequency. This enabled the tremendous benefits of IF filtering and amplification which can be found in virtually all modern radio receivers. The consequences of unintentional frequency mixing likely first came to light in these early days of radio broadcasting.
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