| 摘要 |
PROBLEM TO BE SOLVED: To reduce the entire power consumption of a receiver and to extend the service life of a battery by reducing the power consumption of a mixer inside a signal path in the case where RSSI signal has indicated that the strength of information signals is large. SOLUTION: RSSI (reception signal strength indicator) signals are used and an RF mixer 220 is switched between a high power mode and a low power mode by using a hysterisis comparator 275. The hysterisis comparator 275 controls a current drawn out from a fixed current source 221. In the case that the RSSI signals are sufficiently large and reliable reception is possible in the low power mode, a high current is switched to a low current inside the RF mixer 220. Further, by incorporating a hysterisis function in a control loop, in the case that antenna signals are changed near a switching threshold value, an instable switching mode is evaded. The execution of the hysterisis function includes a gentle transition area for not sharply changing the current inside the current source. |
