Flasher type multi-frequency fish finder

A flasher-type multi-frequency fish finder for indicating an underwater-detection result, comprising:

• a wideband ultrasonic transducer that transmits ultrasonic waves into water and receives reflected signals from that water;
• a display-rotating disk having a plurality of display LEDs on the display surface;
• a motor that rotates the display rotating disk;
• and
• a control device that produces a light emission signal to cause the display LED to emit light based on a reflected signal;
• with the control device including:
• a signal separating and obtaining part that separates a reflected signal into three or more types of frequency components including a first-frequency component, a second-frequency component and a third-frequency component, and obtains a first-reflected signal corresponding to the first-frequency component, a second-reflected signal corresponding to the second-frequency component and a third-reflected signal corresponding to the third-frequency component;
• and
• a light emission signal producing part that produces a first-light emission signal based on the first reflected signal, a second-light emission signal based on the second reflected signal, and a third-light emission signal based on the third reflected signal;
• wherein, the emission-signal-producing part performs:
• a luminance modulation of the first reflected signal to replace its intensity with the luminance, thus producing the first emission signal that causes the display LED to emit light in the first chromatic color;
• a luminance modulation of the second reflected signal to replace its intensity with the luminance, thus producing the second emission signal that causes the display LED to emit light in the second chromatic color different from the first chromatic color;
• and
• a luminance modulation of the third reflected signal to replace its intensity with the luminance, thus producing the third emission signal that causes the display LED to emit light in the third chromatic color different from the first and second chromatic colors;
• therein, an annular display region is set on the display surface, and underwater detection results, obtained by using three different types of ultrasonic frequencies, are simultaneously indicated by a flashing light in the annular display region.