| 摘要 |
<p>An inexpensive and low power consumption frequency synthesizer in which sufficient frequency switching characteristics and spurious characteristics can be obtained without substantially raising the phase comparison frequency. A variable frequency divider (7) divides the oscillation signal of a VCO while switching the frequency dividing ratio in accordance with an integral frequency dividing ratio generated by frequency dividing ratio generating means (8), and controls VCO with an output of a loop filter (5), and frequency dividing ratio generating means (8) comprises multiple integrators connected in cascade and differentiators which differentiate the carry-out signals of the integrators (100, 101), so that a phase error generated at the variable frequency divider (7) is obtained from an output of an adder included in the final stage integrator of frequency dividing ratio generating means (8), and a phase error compensation value is output, and further a pulse width of a signal to be used for compensating for phase error is varied in accordance with the phase error compensation value to perform compensation for the phase error. <IMAGE></p> |
