| 摘要 |
<p>PURPOSE:To reduce power consumption and to make the device small in size by employing a surface acoustic wave matching filter in matching with a signal wave subject to biphase modulation by a unique word pattern so as to constitute a unique word detector. CONSTITUTION:A base band data being an input signal is inputted to a mixer 3, where the data is subject to biphase modulation. Then the wave subject to biphase modulation is inputted to a surface acoustic wave matching filter 4. The filter 4 upon the receipt of a signal wave of IF band subject to biphase modulation by unique word pattern outputs a sharp peak signal corresponding to a correlation value. An output signal of the filter 4 is inputted to a mixer 5 and converted into a base band signal by synchronizing detection. The converted base band signal is subject to threshold level decision by a threshold level decision circuit 6 and the circuit 6 generates a unique word detection pulse when the level exceeds a predetermined threshold level. Moreover, the received phase is decided simultaneously. Through the constitution above, since the correlation value is obtained by the filter 4 being a small sized passive element, the power consumption is low and the size is small.</p> |
