A method for filtering user information takes into account not only specific keywords in the user information, but also related user-characteristic data, and allows targeted user characteristics to be determined from multiple aspects of user activities. 1 to 1 nm above silicon-germanium; and depositing a silicon oxide layer on the substrate. Then, in each transmission channel, the coded signals allocated thereto are analog summed to generate a modulation signal, and a transmission signal is modulated in response to the modulation signal.