A digital device to make speech in a helium atmosphere more intelligible includes a recirculating storage and an analog to digital converter which periodically samples the speech and the digital samples are loaded into the storage at a rate determined by a load counter. An unload counter continuously operating at a predetermined slower rate than the load counter unloads the stored digital representations of the speech and a digital to analog converter converts it back to an analog signal. The analog signal is utilized by an output means such as a loudspeaker and is an intelligible translation of the input speech. Since the storage is loaded at a faster rate than it is unloaded, it will periodically fill up, and no more digital samples are loaded, until such time as the storage is again emptied.
3924069 - Helium speech decoder - Owned by The United States of America as represented by the Secretary of the Navy (Washington, DC) [*] Notice:The portion of the term of this patent subsequent to January 28, 1992 has been disclaimed.
A helium speech decoder of the type that may be used to an advantage by drs living, working, and communicating in and from deep water habitats is disclosed as including a microphone, a digital-to-analog converter, a battery of pairs of shift registers, a like battery of select gate circuits, an analog-to-digital converter, and earphones. A programmable generator produces a plurality of control signals which are timely supplied to the aforementioned components as necessary to effect the concerted operation thereof in such manner as to cause a pitch scaling, reduction, or decoding of the human speech that is spoken in a pressurized helium-oxygen environment, without substantially changing the syllabic or word rate thereof. A filtered fundamental frequency of said human speech is optionally added to the decoded portion thereof to enhance the fidelity thereof.
3863026 - HELIUM SPEECH DECODER - Owned by The United States of America as represented by the Secretary of the Navy (Washington, DC)
A helium speech decoder of the type that may be used to an advantage by drs living, working, and communicating in and from deep water habitats is disclosed as including a microphone, a digital-to-analog converter, a battery of pairs of shift registers, a like battery of select gate circuits, an analog-to-digital converter, and earphones. A programmable generator produces a plurality of control signals which are timely supplied to the aforementioned components as necessary to effect the concerted operation thereof in such manner as to cause a pitch scaling, reduction, or decoding of the human speech that is spoken in a pressurized helium-oxygen environment, without substantially changing the syllabic or word rate thereof. A filtered fundamental frequency of said human speech is optionally added to the decoded portion thereof to enhance the fidelity thereof.
A frequency band converter wherein a signal whose frequency band is to be converted is written in a random access memory at a predetermined cycle while the contents of the random access memory are read out sequentially at a cycle different from the writing cycle thereby to obtain a frequency band converted output signal.
Accelerated or retarded signal playback is accomplished by writing the information alternately into one shift register at one clock frequency and reading out from the other shift register at another clock frequency. Feedback from a selectable last stage "main" output or from an "auxiliary" output intermediate stage of a shift register permits repetition of differing portions of the signal segment, to provide improved quality of reproduction for burst signals such as plosive sounds in speech.
A method and system for transmitting biomedical data to a remote station for subsequent processing. Analog electrical biomedical signals are sampled and digitized at a relatively low data rate and transmitted over a communications link of limited bandwidth to a remote station where the analog electrical biomedical signals are reconstructed from the digital data and are sampled and digitized at a substantially higher data rate for subsequent interpretation by a diagnostic computer. Alternatively, the received digital data are directly converted to a substantially higher digital data rate by means of a numerical algorithm, a form of digital interpolation.
