| 摘要 |
A multi-frequency comb generator (2-4; FIG. 1) for radar and the like using a feedback loop through a frequency multiplier, such as for example, a doubler (3). A reference or master oscillator output goes through a directional coupler (2), for example, a ten dB coupler with twenty dB directivity, to the frequency doubler and then an amplifier (4). The amplifier output is superposed on the reference oscillator output (1) and is applied to the input of the doubler. Frequency doublers, when driven by multiple frequencies, cross modulate and generate sum and difference frequencies, which in going around the loop are fed back to the input, resulting in a comb of frequencies (5). As part of the frequency selecting section of a radar exciter (FIG. 2) the comb of frequencies and the output of a parallel frequency multiplier (8) are fed to a mixer (7), and the mixer's output, along with the coupled output ("Nxf"; 6) from the parallel frequency multiplier (8) is filtered & switched in a switched filter bank (9) and then amplified (10). The final output (11) is a signal including "[N+/-(1, 2, 3, 4 . . . )]xf" and "Nxf", where the frequency of the final signal output is selected by the switched filter bank.
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