| 摘要 |
PURPOSE:To shorten the switching time from an active line whose quality is deteriorated into a standby line by providing a transversal equalizer, taking exclusive OR between an output of an A/D converter after equalization and an output of the A/D converter before the equalization and taking the result as a switching instruction. CONSTITUTION:Transversal equalizers 1I, 1Q for I and Q channels are provided and EX-OR4I and EX-OR4Q receive outputs D2I, D2Q of A/D converters 2I, 2Q before equalization and outputs D3I, D3Q of A/D converters 3I, 3Q after equalization respectively to take exclusive OR, the resulting gate outputs are inputted to an OR circuit 5, where they are ORed. Then an output of the OR circuit 5 is integrated by a prescribed time by one period of an input signal string at an integration device 6 and a DC voltage V of the integration output is used as a switching instruction from an active line having waveform distortion into a standby line. Thus, the time of line changeover from the active line whose reception quality is deteriorated into the standby line is decreased. |
