| 摘要 |
<p>PURPOSE: To prevent occurrence of an identification error of a demodulation signal due to deteriorated S/N by detecting a level of a demodulation output of a SAW matched filter and using the result for a reference signal for discriminating the identification after detection. CONSTITUTION: A level of a burst demodulation output of a correlation demodulation section 1 is detected by a level detection section 7 and given to a positive comparator section 3, inverted by a polarity inversion section 8 and given to a negative comparator section 4 respectively as comparison reference voltages. The comparison reference voltages of the comparator sections 3, 4 are changed in response to a change in the detection level of the delay detection signal 2 due to fluctuation in the reception signal level. Thus, stable data demodulation is attained against the reception level fluctuation due to a change in the radio transmission environment. Part of an output of a synchronization pulse generating section 6 is given to a band limit section 26, in which a sine wave with the same period as that of the demodulated burst signal is extracted and given to a comparison reference signal to the negative polarity comparator section 4 to improve the dynamic characteristic and the reception S/N.</p> |
