Patent ID: 6072992
Filing Date: 2000-06-06
Classification: H01F,H03B,H03J,H03L,H04L

Abstract:
A high frequency apparatus comprising an input terminal for inputting digital modulated high frequency signals, a mixer which receives at one input the signals imputted to input terminal and at the other input an output signal of local oscillator, and an output terminal to which the output signal of mixer is delivered;said local oscillator being comprised of a voltage controlled oscillator, a frequency divider, a phase comparator and loop filter, the last three items disposed intervening in the control loop, said voltage controlled oscillator being comprised of an oscillating section and a tuning section, which tuning section being comprised of a frequency adjusting section and a means for maintaining a state of the frequency adjusting section after adjustment; wherein said control loop has a loop band width so that the noise of said local oscillator is not dominated by the noise of said voltage controlled oscillator, andthe signal level of the reference frequency signal supplied to said phase comparator is made to be smaller, relative to a comparative signal supplied from the frequency divider to the comparator, in a respective frequency excluding a portion substantially at the center of the frequency.