| 摘要 |
<p>A simplified structure is disclosed for a dual-band, double-conversion superheterodyne receiver. All mixer-injection signals are generated by combining the outputs of two phase-locked frequency synthesizers driven by a single reference oscillator. The output of one synthesizer injects the receiver's second mixer, which converts signals from the first intermediate frequency to the second intermediate frequency. The output of the other synthesizer has two uses: (1) it provides first mixer injection needed to tune the receiver to a primary band, and (2) it is mixed with the output of the first synthesizer to provide the first mixer injection needed to tune the receiver to an alternate band.</p> |
