| 摘要 |
A frequency-hopping oscillator (72, 136, 170, or 190) includes a phase-locked oscillator (74, 152, 172, or 196). The phase-locked oscillator (74, 152, 172, or 196) includes both a digital integrator (82 or 146) and a lead compensator (84, 148, or 180), and uses either analog (108) or digital (184) summation of integration and lead-compensation signals to provide a lead-compensated digital integrator (86, 150, or 182). The frequency-hopping oscillator (72, 136, 170, or 190) is adaptive in that it develops channelizing voltage via analog components, such as a VCO 20 and an improved D/A converter 98. The improved D/A converter 98 is designed to prevent "holes" even if a larger number of bits are processed using low-precision resistors. The improved D/A converter 98 is further characterized as being nonlinear (286), producing a lower output voltage (280) by a higher bit than by a total output voltage (278) produced by all lower bits, and producing an output voltage by one bit that is less than twice the output voltage of the next lower bit.
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