Hydrosonic diving communication amplifier system

Claim 1

In a diving system having gas-flow noise as gas is fed to a diver, an improvement is provided for reducing the electronically communicated level of said gas-flow noise from a microphone to a remote speaker comprising: means for preamplifying the composite signals composed of gasflow noise and audio communications coupled to said microphone; means for filtering the preamplified composite signals coupled to the preamplifying means to define a passband between 300 and 2,500 Hz; a long conductor reaching from the filtering means tending to distort the composite signal passband; means for selectively varying the magnitude of said composite signals coupled to Said long conductor; a bandpass filter section connected to the selectively varying means and having the same lower and upper limits as the filtering means for enhancing the lower and upper roll-off rates and to reduce the transfer of distortion attributed to said long conductor; a band elimination notch filter section coupled to receive said composite signals within said passband, being formed of discrete components for attenuating a narrow-band concentration of said gas-flow noise centered on a predetermined noise frequency along with a narrow band portion of said audio communication while passing signals representative of intelligible audio communications to said speaker; and means for amplifying the attenuated composite signal to pass the signals representative of intelligible audio communications to said speaker, the amplifying means being coupled between the notch filter section and the speaker.

Claim 4

A method of ensuring the transfer of signals representative of intelligible speech from a diver''s microphone to a remote speaker as composite signals formed of vocal communications and gas-flow noise impinge on the diver''s microphone comprising: preamplifying said composite signals at the diver''s microphone, filtering the preamplified composite signals to attenuate the low frequency components below 300 Hz and to attenuate the higher frequency components above 2,500 Hz, transmitting the attenuated composite signals from the diver to the remove speaker, shaping the transmitted composite signals at the remote speaker to reattenuate the low frequency components below 300 Hz and to reattenuate the higher frequency components above 2,500 Hz to sharpen the cut-off of the bandwidth of the attenuated composite signals and to filter out distortion caused by transmission from the diver to the remote speaker, notching out the concentrated gas-flow noise and a narrow band of the vocal communications from the reattenuated composite signals leaving signals representative of intelligible speech, refiltering the intelligible speech passband to provide a notched passband between 300 and 2,500 Hz, amplifying the notched passband, and feeding the amplified notched passband to the speaker for the projection of signals representative of intelligible speech.

Claim 5

A method of ensuring the transfer of signals representative of intelligible speech from a diver''s microphone to a remote speaker as composite signals formed of vocal communications and gas-flow noise impinge on the diver''s microphone comprising: preamplifying said composite signals at the diver''s microphone, filtering the preamplified composite signals to attenuate the low frequency components below 300 Hz and to attenuate the higher frequency components above 2,500 Hz, transmitting the attenuated composite signals from the diver to the remove speaker, shaping the transmitted composite signals at the remote speaker to reattenuate the low frequency components below 300 Hz and to reattenuate the higher frequency components above 2,500 Hz to sharpen the cut-off of the bandwidth of the attenuated composite signals and to filter out distortion caused by transmission from the diver to the remote speaker, notching out the concentrated gas-flow noise and a narrow band of the vocal communications from the reattenuated composite signals leaving signals representative of intelligible speech, refiltering the intelligible speech passband to provide a notched passband between 300 and 2,500 Hz, amplifying the notched passband, and feeding the amplified notched passband to the speaker for the projection of signals representative of intelligible speech.