GB1209097A - Recording apparatus for echo sounding systems - Google Patents

Abstract

1,209,097. Recording-apparatus. SIMONSEN & MUSTAD A.S. Aug.30, 1968 [Sept.4, 1967; Aug. 19, 1968], No.41579/68. Heading G1J. A recording-apparatus for echo sounding systems comprises a plurality of marking devices 3 arranged across the width of a strip 1 and switches 4 receiving output signals from an echo signal receiver and selectively from either a pulse generator 8 or 15 (the latter generating pulses of higher repetition frequency) so that the marking devices 3 are sequentially connected to the echo signal receiver at a frequency depending on the generator selected. The switches 4 comprise a plurality of twoinput AND gates whose outputs are connected respectively to the marking devices 3. Each has an input connected to an echo signal receiver 12 and another connected to a ring counter 6, 7 so that with a switch 16 in normal position, the devices 3 receive pulses sequentially from the generator 8, pre-set to a rate conforming with the depth range to be sounded. A suitable interval after the emission of a pulse by a transmitter 13, the ring counter operates and, when the echo is received, receiver 12 supplies a signal to the gates 4 (to cause a mark to be made) and also to an amplitude-sensitive discriminator 17 which controls the switch 16. When the signal exceeds a predetermined value, a sensitive element 17a triggers a multi-vibrator 17b and a gate 16b opens while a gate 16a closes, disconnecting generator 8 and connecting generator 15. At the higher frequency the marks are faint and to ensure that one device 3 will make a normal record of a signal exceeding the set value, an additional potential on a lead K derived from generator 8 is required to effect switching. The transfer back to generator 8 from 15 can take place after a predetermined time or by other means suggested. As an echo from the sea bed is the usual cause of the change to the higher frequency and more rapid scanning of the strip 1, time is saved over the part of the echo period which does not serve a useful purpose. Further time can be saved by terminating the sounding period when the switch 16 switches back to normal.