DATA TRANSMITTER-RECEIVER

摘要

PURPOSE:To reduce deterioration due to a strong interfering wave or frequency selective distortion and to eliminate the need of a broad band delay device for delay detection by letting only part of a signal band be a reception band and revising a frequency or a band width of the reception band in response to the reception state. CONSTITUTION:A spread spectrum signal (a) whose period of a spread modulation signal is equal to a symbol period of data are equal to each other is inputted to a variable band pass means 21, in which only a component of a partial band is extracted and an intermediate frequency signal (b) is obtained, A delay detector 12 detects the intermediate frequency signal (b) to obtain a detection output (c). A decoder 16 reproduces data from the detection output (c) and outputs decoding data (d). A reception state discrimination means 24 discriminates the reception state based on the detection output (c) and the decoded data (d) and switches a center frequency or a band width of the variable band pass means 21 when the reception state is defective.