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发表于 2020-6-15 16:59:30
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Typical RF switches are designed only for switching purposes without considering frequency selectivity or filtering. A separate filter is normally used with a switch
to provide a filtering function. For instance, a band-pass filter is typically needed
between the antenna and transmit/receive (T/R) switch to suppress unwanted signals arriving from the antenna before going to the receiver’s low-noise amplifier (for
receiving) and coming out of the transmitter’s power amplifier before reaching the
antenna (for transmitting). This conventional design approach leads to higher insertion loss, larger size and higher cost for RF systems. To overcome these problems, it
is logical to combine filter and switching functions in the design to produce a single
circuit that is capable of simultaneous switching and filtering, while keeping the size
comparable to that of a corresponding switch without filtering capability. |
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