A signal isolator has an acoustic transmitting medium with a first pair of acoustic transducers thereon for transmitting an input signal through the medium at a first frequency. A first transmitting and receiving circuit is used in combination with the first pair of transducers. A second pair of transducers is located on the acoustic medium to transmit a power supply signal through the medium at a second frequency. Power supply means associated with the power supply signals are used to energize ...

A signalling device for underwater divers, in the form of an inflatable bladder held within a container and attached to a reel. The device can be attached to a diver, being strapped to his arm or to his air tank, for example. The device can be actuated by pulling a handle, which releases a gas cartridge to inflate the bladder as it is simultaneously released from the container to float to the surface. Rescuers can then follow the line down to the reel to locate the diver.

A digital synthesizer is disclosed for generating complex waveforms of seted multiple frequencies and selected phases in the time domain. A plurality of independent frequency sources each produces square waves at its selected fundamental frequency and at frequencies which are integral multiples, such as twice, four times and eight times, that of the fundamental. A sampling clock whose frequency is at least the highest frequency produced by any frequency source, multiplied by the number of fundam...

A signal system includes a switching element which is turned on or off in response to an electrical signal. The signal system includes a field effect transistor which is arranged such that the drain current does not change in response to a variation in voltage across the source and the drain of the transistor, whereby every signal is applied to the switching element when a circuit voltage is applied to the switching element while a signal is prevented from being applied to the switching element ...

Both wide-band and narrow-band noise suppression can be achieved by the disclosed signal normalizer in which the properties of hard limiting and adaptive control weights are fully utilized.

A simultaneous multichannel signal generator incorporating phase-locked l frequency correction. For each channel, there is a voltage-controlled oscillator (VCO) set to an appropriate frequency by a tuning signal and modulated by a channel data signal. The output signals from all VCO's are provided to a summer and then are appropriately amplified and filtered for transmission. A single multiplexed frequency correction circuit compares the phase of a reference frequency signal with the phase of a ...

A voter for providing a single accurate output signal that is derived from the closest two signal levels of three input signals, each of which signals represents a measurement of the same phenomena. By means of the voting circuit, the signals are first sorted by level of amplitude and then ranked as highest, middle or lowest. The highest or lowest signal that is furthest from the middle signal is rejected, while the other highest or lowest signal is selected for processing. The selected high or ...

A signal processor having a plurality of charge transfer devices adapted for coupling to an input signal source. Each one of such devices produces a sample of the input signal in response to a sampling signal. An input shift register having a plurality of serially coupled stages is provided, each one of such stages being coupled to a corresponding one of the charge transfer devices. Circuitry is included for enabling the sampling signal to be sequentially produced at an output of each one of the...

A television test line signal generator comprising a read-only memory which is read under the control of a clocked counting circuit, memory outputs being connected via a clocked buffer store to a digital-to-analogue converter, which is followed by a signal filter. The information in the read-only memory is programmed versus signal distortions following thereafter.

The present invention relates to a signal acquisition network comprising an automatic phase/frequency control network suitable for automatic fine tuning with a wide frequency scanning feature, operative during signal acquisition. Wide frequency scanning is provided by a self quenching oscillator, which provides a low frequency "dithering" voltage to the AP/FC network to facilitate signal acquisition. The arrangement permits one to combine a large capture bandwidth with accurate narrow band tunin...