Fish finder capable of discriminating sizes of fish
First Claim
Patent Images
1. A fish finder capable of discriminating the sizes of fish, comprising:
- a single transducer capable of transmitting and receiving high- and low-frequency ultrasonic sound waves simultaneously, one of said high- and low-frequency ultrasonic sound waves being emitted with a wide beam angle while the other of said waves is emitted with a narrow beam angle;
receivers for processing the high- and low-frequency echo signals received by said transducer,a subtractor circuit for subtracting the received echo signal corresponding to the narrow beam angle from the received echo signal corresponding to the wide beam angle, anda recorder for recording the output from said subtractor circuit comprising echo signals corresponding to images of fish of desired size.
0 Assignments
0 Petitions
Accused Products
Abstract
The present invention discloses a fish finder wherein one transducer is used to generate both high- and low-frequency ultrasonic waves which are simultaneously emitted and the electrical signal representative of the reflected high- or low-frequency ultrasonic waves is extracted by the signal representative of the reflected low- or high-frequency ultrasonic waves, thereby discriminating the sizes of fish detected.
-
Citations
3 Claims
-
1. A fish finder capable of discriminating the sizes of fish, comprising:
-
a single transducer capable of transmitting and receiving high- and low-frequency ultrasonic sound waves simultaneously, one of said high- and low-frequency ultrasonic sound waves being emitted with a wide beam angle while the other of said waves is emitted with a narrow beam angle; receivers for processing the high- and low-frequency echo signals received by said transducer, a subtractor circuit for subtracting the received echo signal corresponding to the narrow beam angle from the received echo signal corresponding to the wide beam angle, and a recorder for recording the output from said subtractor circuit comprising echo signals corresponding to images of fish of desired size. - View Dependent Claims (2)
-
-
3. A fish finder capable of discriminating the sizes of fish, comprising:
-
a single transducer capable of transmitting and receiving high- and low-frequency ultrasonic sound waves simultaneously, receivers for processing the high- and low-frequency signals received by said transducer, a subtractor circuit for subtracting one of said received high- and low-frequency signals from the other of said signals, means for determining when the received low-frequency signal has an amplitude exceeding a predetermined threshold value, and for thereupon detecting and differentiating said received signal and adding the resulting detected and differentiated signal to the output of the subtractor circuit to provide a signal enhancing the sea bottom, and a recorder for recording said enhanced signal.
-
Specification