| 摘要 |
A wide band oscillator with phase lock loop is controlled by signals from an 40 MHz harmonics generator combined with the output of another phase lock loop controlled oscillator whose selectible outputs vary in MHz steps with a total range of 39 MHz. The phase lock loop of the wide band oscillator is additionally controlled by a d/a converter and by another phase lock loop controlled oscillator whose selectible outputs vary in one KHz steps. Each of these phase lock loops is digitally controlled from the input frequency selection and again therefrom via a digital-to-analog converter. The output of the wide band oscillator is combined with the output of a narrow band oscillator which may be FM modulated. Alternatively, an output amplifier for the combination difference frequency may be AM modulated.
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