| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication equipment with a small scale whose band width is variable in the frequency division multiplex communication. SOLUTION: In a multiplexer at a transmitter side, an A/D converter 3 converts each channel signal into a digital signal, a complex multiplier 5 converts the signal into a complex signal with different frequency for each channel interval Δf and the signal is fed to an IFFT circuit 8 conducting inverse Fourier transformation via a switch circuit 6 having plural switch elements 7. Nyquist characteristic digital sub filters 10-1 to 10-N whose Nyquist frequency of Δf/2 are arranged to the output of the IFFT circuit 8 and outputs of the digital sub filters 10-1 to 10-N are added by an adder circuit 12 via delay devices 11-1 to 11-N. A demultiplexer at a receiver side is configured similarly to the multiplexer. The band width is changed by changing the state of each switch element 7. |
