| 摘要 |
<p>PURPOSE:To obtain a signal processing circuit with high performance at a same data processing speed by providing a digital filter passing through only a desired frequency band from among data digitized by an A/D converter so as to decrease the sampling frequency. CONSTITUTION:Analog LPFs 1a, 1b filter an I/Q video signal respectively to eliminate the influence of folding of a frequency component caused at the time of discreteness of A/D converters 2a, 2b on a next stage. The pass band of the LPFs 1a, 1b is made a desired band and the sampling frequency of the A/D converters 2a, 2b is made twice or move the desired frequency band. A digital filter 3 passes through only a signal of an object frequency and a decimeter 4 thins the time series data to decrease an arithmetic operation rate. Then the data as the low speed are subjected to FET arithmetic operation by a FET processing unit 5 and the frequency of the desired signal is obtained from both the pass band of the filter 3 and the frequency of the folded signal.</p> |
