| 摘要 |
PURPOSE: To improve the accuracy of data demodulation in the after-demodulation correlation system being one of demodulation systems demodulating original data from a spread spectrum signal. CONSTITUTION: The correlation device is made up of a 1st product sum arithmetic section 7 conducting product sum arithmetic operation between a digital binary signal string D1 obtained by applying tip-demodulation to a spread spectrum signal whose frequency is converted into a frequency at an intermediate frequency band on a reference signal string being the same spread code as that of a transmitter side, a 2nd product sum arithmetic section 8 in cascade connection to the arithmetic section 7 so as to receive the binary digital signal string outputted from the arithmetic section 7 and conducting sum of products arithmetic operation between the received digital signal string and a reference signal string being the same spread code as that of a transmitter side, and a discrimination section 9 that discriminates whether or not autocorrelation is taken as to either of the product sum arithmetic data in the 1st product sum arithmetic section 7 and the sum of products arithmetic data in the 2nd sum of products arithmetic section 8 and recovers the data when it is discriminated that autocorrelation is taken as to at least either of the sum of products arithmetic sections. |
