| 摘要 |
PURPOSE:To attain long distance data reception of the 1:n station broadcast type with high quality by allowing one reception system of two systems to select automatically an optimum frequency depending on the line quality changing timewise for mobile body reception and using the diversity reception system to the optimum frequency so as to apply continuous reception. CONSTITUTION:A data subject to PSK (phase shift keying) or FSK (frequency shift) by a modulator 22 at a fixed station A0 and irradiated in plural frequencies at the same time from transmitters TX1, TX2... is received by the diversity two system of a space/polarized plane at mobile stations A1, A2... and an S/N comparator 35 supervises the S/N in the unit of bits and controls a switch 36 to select a better channel. When the optimum frequency is selected at that time on a halfway of reception and it is desired for change, one system of diversity reception continues the reception of the preceding frequency and the other system switches sequentially and receives the reception frequency channel of the receiver in time division, the optimum reception frequency is decided selectively based on the error detection of the reception data or the received S/N and both the systems select the optimum frequency and continue the reception. |
