Abstract: An apparatus for low power radio communication comprising a transmitter having a frequency synthesizer and transmit antenna such that the frequency synthesizer comprises a phase locked loop circuit with a voltage controlled oscillator having a variable frequency output and with a loop filter/sample and hold circuit that allows opening of the synthesizer control loop and with special means of limiting the resulting frequency drift in the open loop state. The transmitter produces an output signal and the loop filter/sample and hold circuit holds the voltage controlled oscillator substantially on frequency such that the output signal remains stable, with a minimum of frequency drift, over a period of time when the phase lock loop synthesizer is set to an open loop state to allow frequency modulation unimpeded by the normal frequency correcting action of the synthesizer and for the frequency synthesizer to be partially powered down to reduce power consumption.

Abstract: The present invention relates to a frequency modulated system, and a method for operating same, including a phase locked loop frequency synthesizer circuit which synthesizes a carrier frequency through the use of an electronically controlled oscillator. The circuit, which has a certain loop bandwidth, includes a reference frequency source and a bypassed correcting integrator. A modulating signal simultaneously modulates the oscillator, the reference frequency source and the bypassed correcting integrator such that the carrier frequency is frequency modulated with a certain frequency deviation. The magnitude of the modulation of the oscillator, the reference frequency source and the correcting integrator are controlled over a frequency range by frequency blending the reference frequency source and the bypassed correcting integrator such that low distortion modulation over a wide frequency range is achieved.

Abstract: A programmable wireless data acquisition system, comprising a transmitting device and a receiving device. The transmitting device is capable of receiving multiple external inputs and generating and transmitting a radio frequency signal encoded with data corresponding to the inputs. The transmitting device is variably configurable to enable it to accept inputs having different characteristics and ranges and to enable it to provide variable sampling rate, gain and filtering of the inputs. The transmitting device having a microprocessor such that the microprocessor controls the operation thereof. The receiving device is capable of receiving the radio frequency signal, demodulating it and decoding the data. The receiving device has a microprocessor such that the microprocessor controls the operation thereof. External programming device programs the transmitting device and the receiving device by wired connection or through radio frequency signal.

Abstract: A pressure relief reminder and compliance system and method to prevent the formation of pressure sores on a person's skin is disclosed. The system comprises sensor which responds according to pressure exerted on the skin; a programmable microcontroller connected to the sensor; means for programming the microcontroller; and indicating means. A programming device operates software to changeably program the microcontroller with certain values of pressure and time, such that the level and duration of pressure on the skin and the duration of the absence of pressure thereon, are compared to the programmed values, is given to the wheelchair user, and the levels and duration of pressure are stored in memory. The programming device also can download from the memory the recorded values for review and analysis by a physician, clinician, therapist or other health professional. The indicators can be an audible alarm, like a beeper or buzzer, or a vibrator.

Abstract: An interface pressure measurement device, comprising a sensor comprising two sensor sheets formed from thin flexible plastic material, each sensor sheet has a sensor area having flexible conductive ink printed thereon comprising a conductive surface with an electrical lead such that when the sensor sheets touch, an electrical contact is present forming a sensor switch, and the sensor also has sensor tubing. A digital device is connected to the sensor by the sensor tubing. The digital device comprises an enclosure, a push button, pressure transducer, signal conditioning, microcontroller with processor, analog-to-digital converter, memory, clock, display, buzzer and battery/power supply wherein the processor interrupts the battery/power supply current flow to shut off the digital device after a preset time.

Abstract: A wireless EEG system for effective auditory evoked response, comprising an electrode array which is adapted to be attached to a person and senses voltages produced by the brain electrical activity of the person; transmitter electrically connected to the electrode array such that the transmitter produces a radio frequency signal corresponding to the voltages sensed by the electrode array, encodes the radio frequency signal with error correcting encoding and transmits the radio frequency signal by radio frequency telemetry through a transmitting antenna; the transmitter utilizing carrier frequency shift keyed circuitry to modulate a phase locked loop synthesized carrier frequency and reference frequency shift keyed circuitry to modulate a reference frequency to allow for non-return to zero format of the radio frequency signal obviating the need for Manchester encoding; receiver that receives through a receiving antenna the radio frequency signal produced and transmitted by the transmitter and whereby the recei