| 摘要 |
When attempting to reduce the number of battery cells in cellular telephones, a frequency synthesizer or phase locked loop located within the cellular telephone will output an increasing amount of noise. In order to reduce the amount of noise output when reducing the number of battery cells in such systems, the present invention employs a voltage step up device which effectively increases the voltage range of a voltage controlled oscillator within the frequency synthesizer. To further reduce the noise, the voltage step-up unit is employed with passive elements thus reducing the noise further and optimizing the output of the phase locked loop. Several different designs are discussed to further reduce space requirements and increase programmability of the system. |
