Abstract: An apparatus for simulating radio frequency (RF) signal propagation characteristics in a wireless communication network is disclosed. The apparatus includes a first RF terminal and a second RF terminal. A first optical modulator is in electrical communication with the first RF terminal. An optical delay line is in optical communication with the first optical modulator. A first optical demodulator is in optical communication with the optical delay line and in electrical communication with the first RF terminal. A second optical demodulator is in optical communication with the optical delay line and in electrical communication with the second RF terminal. A second optical modulator is in electrical communication with the second RF terminal and in optical communication with the optical delay line.

Abstract: The present invention relates to filter, coherent receiver device and coherent receiving method. The filter is used for converting a partial response signal into a full response signal, wherein the filter uses the following transfer function HPre-Filter(z) with respect to a partial response signal having a transfer function H PR ? ( z ) = A ? ( 1 + z - 1 ) m ? ( 1 - z - 1 ) n : ? ? H Pre - Filter ? ( z ) = 1 A ? ( 1 + ? ? ? z - 1 ) m ? ( 1 - ? ? ? z - 1 ) n , in which A is other item, m and n are integers larger than or equal to 0 but not being 0 at the same time, 0<?<1.