| 摘要 |
<p>PURPOSE:To increase a processing speed by converting a received signal from analog to digital and then dividing it into plural frequency bands by digital filters, and lowering their rates to necessary data rates by data thinning out filters and inputting the signals to a memory. CONSTITUTION:A received signal which is reflected by the surface of the sea and received by a receiver is sampled and quantized by an A/D conversion part 1. Then the output digital signal of the conversion part 1 is divided into the four frequency bands by the 1st-4th digital filters 2-5. Then the outputs of the filters 2-5 are passed through 1st-4th data thinning out filters 4-9 so as to lower their data rate to the data rates matching with the respective band widths. Consequently, the signals of the respective bands which are lowered to the data rates are multiplexed and stored in the input memory 10. The data stored in the memory 10 is transferred, band by band, to a Doppler filter 11 to generate filter banks by Fourier transformation, thereby dividing an observation area. Thus, the processing speed is increased.</p> |
