| 摘要 |
<p>PURPOSE:To enable the discrimination of a target having a large pulse width, such as a large- sized ship, from the land and mountains, and also the discrimination of the echo of a small- sized target overlapping them, by utilizing the fact that the small-sized target overlapping the land and mountains has a negative amplitude when the difference between a non-delay signal and a delay signal is determined. CONSTITUTION:A digitized reception video signal (a) is inputted in a comparison circuit 1a. In this circuit, the signal is compared with a threshold value set by a threshold value generating circuit 11a, and a signal D4 of logic 1 and 0 is delivered therefrom. The signal D4 is sent to a gate signal generating circuit 2 and inputted in a delay circuit 12 with a tap, wherefrom five kinds of signals whose inputs are delayed by a time T are generated. Meanwhile, the reception video signal (a) is adjusted in timing by a delay circuit 3a and further delayed by 1T in a delay circuit 3b, and a delay signal D10 is generated therefrom. An operation circuit 5 makes a signal D9 pass as it is when D1 is logic O, while making an operation of D9-D10 when D1 is logic 1. An output signal D3 of the operation circuit is branched and sent to a reset signal generating circuit 7, and further is inputted in a comparison circuit 1b. In this circuit, comparison is made with a negative threshold value set by a threshold value generating circuit 11b. A reset signal is generated from the pulse width of the video signal (a), and by this reset signal, the output of the operation circuit 5 is reset.</p> |
