SHIP SPEED CORRECTION SYSTEM OF SHIP SPEED MEASURING APPARATUS

摘要

PURPOSE:To enable adjustment within a short time, by providing a frequency dividing means for forming a ship speed signal by dividing the frequency of a clock pulse on the basis of a preset frequency dividing ratio and a frequency dividing ratio setting means for freely setting a frequency dividing ratio to said frequency dividing means. CONSTITUTION:When a ship goes astern, an increment/decrement change-over signal goes to L and is reversed by a reversal circuit 7 to become H and the gates of AND gate circuit 4b, 4a are respectively opened and closed. Because of this, the high frequency clock pulse outputted from a Doppler shift detection circuit is inputted to the decrement count terminal D of a presettable increment/decrement counter 1. In the counter 1, the increment/decrement change-over signal and the high frequency clock pulse are inputted to a NAND gate circuit 3b and a load signal is applied to a load terminal Ld to preset a frequency dividing ratio N set by a digital switch 6. The count 1 performs decrement counting from the frequency dividing ratio N each time a clock is inputted and, at the time of zero arrival, a borrow signal is outputted and, by the actions of an OR gate circuit 3a and the NAND gate circuit 3b, the frequency dividing ratio becomes N+1 when the next (N+1)-th clock is high. This remain the same when the ship makes headway.