| 摘要 |
PURPOSE:To attain low power consumption by correcting the change in a control voltage to a VCO at PLL loop disconnection and executing intermittently the PLL operation in a PLL frequency synthesizer. CONSTITUTION:When the loop cut-off switch 310 is turned off by a control signal from a loop cut-off controller 316, a change is produced to a control voltage to the VCO301. Then a correcting signal is formed based on an output signal of a triangle wave generating circuit 312 and injected to a loop filter 309 via a correction signal injecting switch 311. Thus, a corrected control voltage is fed to the VCO301 from the loop filter 309. On the other hand, when the switch 310 is turned off, the power supply to a prescaler 303, a TCXO307 and a PLL LSI 317 is stopped. The PLL operation is executed intermittently by the interruption of the power supply. Thus, low power consumption is attained. |
