Echo sounder transmitting radiant energy at two frequencies
First Claim
1. In an echo sounder including means for transmitting, into a medium, acoustic signals at two slightly differing high frequencies and in the form of pulses, resulting in the creation of an acoustic signal in the medium at a low frequency equal to the difference between the two high frequencies, and receiving means including a first receiving transducer for receiving echoes of acoustic signals at the difference frequency, a second receiving transducer responsive to high signal frequencies for receiving echoes of acoustic signals at at least one of the two transmitting frequencies, and display means connected to both receiving transducers for recording the echo signals generated thereby according to their travel times, the improvement wherein said transmitting means are constructed and oriented for transmitting the acoustic signals at the two high frequencies with directional characteristics creating substantially coextensive spread angles so that the spread angle of the low frequency acoustic signal is substantially coextensive with that of each high frequency acoustic signal, and said display means has a single input to which each of said first and second receiving transducers is connected for causing the low frequency echo signals and the echo signals at the at least one high transmitting frequency to be supplied to the same input of said display means.
2 Assignments
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Accused Products
Abstract
An echo sounder including a unit for transmitting, into a medium, acoustic signals at two slightly differing high frequencies and in the form of pulses, resulting in the creation of an acoustic signal in the medium at a low frequency equal to the difference between the two high frequencies, and a receiving unit including a receiving transducer for receiving echoes of acoustic signals at the difference frequency and a display device for recording the echo signals in accordance with their travel times, the display device having a signal input which is connected with the low frequency receiving transducer, is further provided with a second receiving transducer responsive to high signal frequencies for receiving echoes of acoustic signals at at least one of the two transmitting frequencies, and a member connecting the second receiving transducer to the signal input of the display device.
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Citations
5 Claims
- 1. In an echo sounder including means for transmitting, into a medium, acoustic signals at two slightly differing high frequencies and in the form of pulses, resulting in the creation of an acoustic signal in the medium at a low frequency equal to the difference between the two high frequencies, and receiving means including a first receiving transducer for receiving echoes of acoustic signals at the difference frequency, a second receiving transducer responsive to high signal frequencies for receiving echoes of acoustic signals at at least one of the two transmitting frequencies, and display means connected to both receiving transducers for recording the echo signals generated thereby according to their travel times, the improvement wherein said transmitting means are constructed and oriented for transmitting the acoustic signals at the two high frequencies with directional characteristics creating substantially coextensive spread angles so that the spread angle of the low frequency acoustic signal is substantially coextensive with that of each high frequency acoustic signal, and said display means has a single input to which each of said first and second receiving transducers is connected for causing the low frequency echo signals and the echo signals at the at least one high transmitting frequency to be supplied to the same input of said display means.
Specification