| 摘要 |
PURPOSE:To detect a signal from a demodulation output under a low S/N by sampling a signal 1-bit by several samples and comparing the bit series with a code from a code generator without forming a bit synchronizing signal. CONSTITUTION:The output of an FSK demodulating circuit 10 is sampled by a sampling device 22 not by signal one bit length but by, e.g., 8 samples. A data outputted from the sampler 22 is inputted sequentially to a shift register 24, 8 data are extracted from the register 24 at the interval of 8 samples and inputted to a comparator 21. The comparator 21 compares a code to be compared and collated every input of one sample with an input signal string and as the result of the comparison, if majority or over is coincident, it is decided that the signal is detected. |
