| 摘要 |
PURPOSE:To grasp a channel corresponding to the mean value of received electric power of respective channels within a specific time and to select the channel of maximum received electric power securely in communication system of car telephone, etc., by detecting the level of the received electric power of each channel in the form of a time rate in the specific time. CONSTITUTION:The received electric power of a channel specified by a processor 7 is inputted from an input terminal IN to a received electric power detecting circuit 1 to be converted into a corresponding DC voltage, which is inputted to a comparing circuit 3 together with a specific reference value (DC voltage) outputted from a reference value generating circuit 2. The comparing circuit 3 compares both inputs with each other and outputs a signal when the DC voltage corresponding to the received electric power is greater than the reference value, and the signal showing that the DC voltage is greater than the reference value is stored in an input port 4. The processor 7, on the other hand, reads and executes instruction words in a program memory 6 stored with a control procedure successively. Thus, the address of the input port 6 is specified to read the storage contents and when it is confirmed that the received electric power is greater than the reference value, the value of a software counter provided in a buffer memory 5 is increased. After the same processing regarding all channels is performed, all channel numbers are compared with each counter value (frequency of surpassing of received electric power above reference value), and the maximum value is selected to specify the corresponding channel number, thus selecting the desired channel and performing acquisition. |
