| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a local oscillator capable of obtaining stable phase noise characteristics independent of PVT in a short time. <P>SOLUTION: The local oscillator includes a digital control oscillator, a phase data generator, a subtractor, a loop filter, a multiplier, and a coefficient calculator. The digital control oscillator is capable of controlling an oscillation frequency of oscillation signals by a first oscillator control value. The oscillation frequency is equal to a product of the first oscillator control value and a change amount of the oscillation frequency per unit value of the first oscillator control value. Setting frequency data are obtained by dividing a setting frequency by a reference frequency of reference signals. The multiplier outputs the first oscillator control value obtained by multiplying a normalized control value from the loop filter by a first coefficient. The coefficient calculator divides the first oscillator control value when the oscillation frequency becomes almost equal to the setting frequency by the setting frequency data, and sets the divided result to the multiplier as a new first coefficient. <P>COPYRIGHT: (C)2012,JPO&INPIT |
