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本文作者提出一种新的方法来制作可变带宽晶体滤波器,其中心频率保持不变,而带宽是可变的。这种新滤波器的灵感来自“Ten-Tec琼斯滤波器”(李·琼斯WB4JTR,美国专利号#5051711)。琼斯滤波器实现可变带宽,但同时伴随着中心频率的偏移。根据应用的不同,这并不总是好的方案。对于一个简单的接收机来说,琼斯滤波器可以发挥其优势,通过设置频移可以使BFO频率两侧都获得不同的带宽,带宽较窄的一端用于CW,带宽较宽的一端用于SSB。
The authors propose a new approach to making a variable bandwidth crystal filter whose center frequency remains the same while the bandwidth is variable. The new filter is inspired by the “Ten-Tec Jones Filter” (Lee Jones WB4JTR, U.S. Patent No. 5051711). The Jones filter achieves variable bandwidth, but is accompanied by a shift in the center frequency. Depending on the application, this is not always a good solution. For a simple receiver, the Jones filter has its advantages. By setting the frequency shift, different bandwidths can be obtained on both sides of the BFO frequency. The narrow bandwidth end is for CW and the wider bandwidth is for SSB .