| 摘要 |
<p>PURPOSE:To prevent the increase of the assembling manhour and the control manhour. CONSTITUTION:The received high frequency signal is converted into a medium frequency signal at a frequency converting part 1 where a local oscillator signal is added and then applied to a demodulator circuit 2 through the automatic gain control processing where the signal band is limited and the signal level is fixed. The medium frequency signal is demodulated to the digital signals of 0 and 1 by the circuit 2 and applied to a 1st frame synchronizing circuit 4 and an inverting circuit 3. The circuit 4 secures the frame synchronization, and the circuit 3 inverts the signal polarity. The output of the circuit 3 is applied to a 2nd frame synchronizing circuit 5 where the frame synchronization is secured. Thus one of both circuits 4 and 5 can always secure the frame synchronization regardless of the signal polarity. A selector circuit 6 selects one of both circuits 4 and 5 that secures the frame synchronization and then outputs a received data signal.</p> |
