A pitch synchronized helium speech unscrambler is disclosed as including a air of bucket brigade analog delay lines which are timely and rapidly loaded with the electrical signal equivalents of human voice signals that are effectively supplied thereto by a receiving transducer. Said voice signal equivalents are then respectively unloaded more slowly from said pair of bucket brigade delay lines than they were loaded therein by a pair of different frequency clock generators driven in alternate successions by preprogrammed signals divided out from a master oscillator and in synchronism with a predetermined pitch portion of the speech signal received by said receiving transducer. The unloaded signals are then broadcast as acoustical voice signals by a transmitting transducer.
The invention relates to a novel helium-speech unscrambler which can be located at a diver's location, and enables the helium-speech voiced by the diver to be subjected to waveform time expansion to reduce the bandwidth of the helium speech (e.g. to 2 to 3 KHZ) prior to transmitting the speech signals to a distant location on a carrier wave selected for optimum transmission through the water.
A radio communication system for simultaneous telecommunication between a calling station and a called station, in which an aural signal to be transmitted from the calling station is divided by sampling pulses in the form of clock pulses of low frequency and is then suitably compressed with respect to the time axis to produce periodic signal-free time regions in the compressor output, so that an aural signal similarly compressed with respect to the time axis and transmitted from the called station can be received within these signal-free time regions. The received aural signal is expanded with respect to the time axis so that the original aural signal output of the microphone in the called station can be reproduced and applied to the speaker in the calling station. A zero cross synchronizing circuit is connected to the compressor to attain zero cross synchronization of the time-divided compressed aural signal and such aural signal is applied to the transmitter.
An analog signal processing system is described for changing the frequency of analog signals in a real-time manner. The system includes at least two analog shift registers, (specifically, three analog shift registers), an input circuit connecting the input end of all the registers in parallel, an output circuit selectively connectable to the output ends of the registers, a high frequency clock pulse source, a lower frequency clock pulse source, and cyclically operable switching means effective to load from the input circuit at least one analog shift register at the rate corresponding to the frequency of one of the clock pulses, while unloading at least one other register into the output circuit at the rate corresponding to the frequency of the other clock pulses. Two applications are described, for purposes of example. One application is as a hearing aid device to reduce the frequency of audio signals in a real-time manner for a person having a limited-frequency audibility. The other application is a communication device for the real-time transmission and reception of audio signals rendering them unintelligible except by receivers equipped with a processing system for reducing the frequency of the received signals.
