Abstract: An alarm apparatus mounted on a vehicle is provided to output an alarm sound around the vehicle. The alarm apparatus generates a sound wave signal having a frequency that is hardly masked by an environmental sound, and outputs an alarm sound based on the sound wave signal.

Abstract: A power supply system uses a DC-DC power converter (28) for supplying an output load. A compensation circuit (40) is connected between the input to the DC-DC converter and the output of the DC-DC converter and it provides a compensating path in response to a voltage drop at the output of the DC-DC converter caused by a surge in the output load. The power supply system further comprises a low drop out regulator (30) as the output load, which low drop out regulator (30) having an input connected to the DC-DC power converter and the compensation circuit, and an output connected to an output terminal (C) for connection to a further output load. This enables the DC-DC power converter to have a low current capability, because a large current demand can be met by the DC supply to the DC-DC converter.

Abstract: In an integrated circuit, a clock monitor circuit detects when an analog clock signal output by an on-chip crystal oscillator has stabilized. The clock monitor circuit uses an envelope follower circuit to monitor the envelope of the analog clock signal and compare the amplitude of the envelope with a predetermined amplitude value. When the predetermined value is reached and the envelope has remained steady for a predetermined time, an oscillator okay signal is generated. If an oscillator okay signal is not detected within another predetermined time, then an oscillator failure signal may be generated.

Abstract: An apparatus includes a vapor cell having multiple cavities fluidly connected by one or more channels. At least one of the cavities is configured to receive a first material able to dissociate into one or more gases that are contained within the vapor cell. At least one of the cavities is configured to receive a second material able to absorb at least a portion of the one or more gases. The vapor cell could include a first cavity configured to receive the first material and a second cavity fluidly connected to the first cavity by at least one first channel, where the second cavity is configured to receive the gas(es). The vapor cell could also include a third cavity fluidly connected to at least one of the first and second cavities by at least one second channel, where the third cavity is configured to receive the second material.

Abstract: Provided is an oscillation stop detection circuit having low current consumption, which is capable of detecting stop of oscillation regardless of whether an input signal stops at High or Low and thereby accurately measuring an oscillation stop detection period. The oscillation stop detection circuit includes: a pulse generation circuit for outputting a one-shot pulse in synchronization with an oscillation signal input from an input terminal; a capacitor including one terminal connected to a first power supply terminal and another terminal connected to an output terminal; a constant current circuit connected between the first power supply terminal and the another terminal of the capacitor; and a switch circuit connected between an output terminal of the pulse generation circuit and the another terminal of the capacitor, for connecting the another terminal of the capacitor to a second power supply terminal based on the one-shot pulse.

Abstract: A semiconductor device includes a first oscillator that generates a first clock signal, a second oscillator that generates a second clock signal in response to the first clock signal, a third oscillator that generates a third clock signal, a counter that counts a signal corresponding to the first clock signal or a signal corresponding to the second clock signal during a predetermined period that is set based on the third clock signal to generate an overflow signal indicating that a count value of the signal corresponding to the first clock signal or the signal corresponding to the second clock signal exceeds a predetermined value, and an abnormality notice unit that receives the overflow signal to generate an abnormal signal indicating that an abnormal oscillation occurs in at least one of the first to third clock signals.

Abstract: An oscillation-stop detection circuit can be manufactured at low cost without requiring controlling difficult manufacturing process conditions. Inverter 30 outputs an oscillation state detection signal. N-channel transistor 26 is a transistor that discharges capacitor 20. A reference voltage generator 21 includes a depletion-mode P-channel transistor 22 of which the gate and source are connected together, and a N-channel transistor 23 of which the gate and drain are connected together, N-channel transistor 23 and N-channel transistor 26 rendering a current mirror.

Abstract: A configurable PSRO measurement circuit is used to measure the frequency dependent capacitance of a target through silicon via (TSV) or other conductive structure. Measurements of the target structure are aided by using adjustable resistors and a de-embedding structure to measure the effects of parasitic capacitance, CPAR. Current is measured to both the device under test (DUT) and the de-embedding structure. From these measurements, the frequency dependent capacitance of the DUT is calculated.

Abstract: A wireless base station (11) includes a wireless communication unit (17) and a clock signal generation unit (20). The clock signal generation unit (20) includes a voltage-controlled oscillation unit (21) that outputs a clock signal of an oscillating frequency according to an inputted control voltage, a time information generation unit (22) that generates time information based on the clock signal, a time information comparison unit (23) that compares the time information with reference time information; and a control voltage instruction unit (24) that instructs a control voltage according to the comparison result to the voltage-controlled oscillation unit (21). Accordingly, the oscillating frequency of the clock signal can be kept easily and highly precisely.

Abstract: A circuit arrangement for detecting voltage changes, comprising supply terminals configured to apply a first potential and a second potential, a first oscillator and a second oscillator, which are operated with the first potential and the second potential, a voltage dependence of the frequency of the first oscillator differing from a voltage dependence of the frequency of the second oscillator, a first evaluation circuit configured to evaluate the frequency of the first oscillator and a second evaluation circuit configured to evaluate the frequency of the second oscillator, and a comparison circuit configured to compare a value based on the evaluated frequencies of the first oscillator and of the second oscillator with a predetermined threshold value, and to output a voltage change signal indicating an impermissible voltage change between the first potential and the second potential depending on the result of the comparison.

Abstract: Control circuitry is disclosed including an oscillator operable to generate an oscillator signal. A frequency of the oscillator signal increases as an amplitude of a first voltage increases up to a threshold, and the frequency of the oscillator signal decreases as an amplitude of the first voltage exceeds the threshold. The oscillator is operable to generate a foldover signal indicating when the frequency of the oscillator signal is decreasing due to the first voltage exceeding the threshold.

Abstract: A crystal oscillator tester includes first and second test pins, first and second transistors, an indicator, a first diode, and first-third capacitors. The first test pin is connected to a power source. The collector of the first transistor is connected to the first test pin. The base of the second transistor is connected to the second test pin. The emitter of the first transistor is grounded via the indicator. The base of the first transistor is connected to the cathode of the first diode. The anode of the first diode is connected to the first test pin via the first and second capacitors one by one in series. The emitter of the second transistor is connected to a node between the first and second capacitors. The collector of the second transistor is grounded. The third capacitor is connected between the base and emitter of the second transistor.

Abstract: A small light-weight battery operated calibrator device provides a precise sine wave output for use in calibration of test equipment, such as a RF Power Meter or a Spectrum Analyzer. The calibration device includes two power levels, one ?40 dBm and one 0 dBm. The purpose of the two power levels is to obtain a slope and offset for correction of the RF power measuring device being calibrated. Operation indication LED lights are provided to indicate which of the two powers are in use, and if battery power is below acceptable levels. Miniature low power components including a crystal oscillator and a divide by 2 integrated circuit that generates a precise square wave and a low pass filter for converting the square wave into a precise sine wave allows the calibrator to be battery operated and stored as a calibration component.

Abstract: System and method are provided for continually monitoring reliability, or aging, of a digital system and for issuing a warning signal if digital system operation degrades past a specified threshold. The technique includes implementing a ring oscillator sensor in association with the digital system, wherein logic and/or device percent composition of the ring oscillator sensor mirrors percent composition thereof within the digital system.

Abstract: A detection device for detecting an oscillator is provided. The detection device includes an oscillator control circuit, a frequency-decreasing circuit and a display circuit. The oscillator control circuit is used for outputting the oscillator signal of the oscillator. The frequency-decreasing circuit is connected to the output of the oscillator control circuit and has a capacitor suitable for charging and discharging and a resistor, which can adjust the time constant of the oscillator signal. The display circuit is connected to the frequency-decreasing circuit for showing the output signal of the frequency-decreasing circuit. The detection device can decide whether the oscillator is normal or broken by observing a component of the display circuit, for example, the twinkling of a light emitting diode of the display circuit.

Abstract: An oscillator and a radar apparatus that includes a resonator electro-magnetically connected to a micro strip line and a rotor connected to the resonator by capacitance. The bottom surface of the rotor has a changing height in the circumferential direction of the rotor. As the rotor is rotated, an actual oscillation frequency is recognized from the rotating angle of the rotor when an output of a detector has a peak. A modulation voltage supplied to a VCO is corrected in accordance with the result.

Abstract: A semiconductor integrated circuit includes a reference-voltage circuit configured to produce a predetermined reference voltage at an output node thereof, a comparator, coupled to a node to which an oscillating signal is supplied and to the output node of the reference-voltage circuit, to produce a result of comparison at an output node thereof, the result of comparison being made by comparing a voltage of the oscillating signal with the predetermined reference voltage, and a detection circuit coupled to the output node of the comparator to produce, in response to the result of comparison, a stable-state-detection signal indicating that the oscillating signal has an amplitude larger than the reference voltage.

Abstract: A control unit having an oscillator for a processor is described, the control unit storing a temporary absence of oscillation of the oscillator in a first error memory, if oscillation begins again after the absence.

Abstract: An operation section 2 is provided to a proximity sensor including: a detection section having an oscillation circuit 10; and an amplification section 2 having a function detecting a metal body using an oscillation amplitude of the oscillation circuit 10. In a set mode, when an operation to set an adjustment value for a sensitivity adjustment (a sensitivity adjustment value) is conducted in an operation section 22, CPU 20 generates a sensitivity adjustment signal in digital quantity indicating the sensitivity adjustment value and outputs the signal to a D/A converter 25. The sensitivity adjustment signal digital-to-analog converted by the D/A converter 25 is given to a feedback circuit 13 through a voltage adjustment circuit 26. Since the feedback circuit 13 is designed so as to change a feedback current quantity according to an applied voltage, a current with a magnitude matching a value the sensitivity adjustment signal is fed back to a resonance circuit 11 to thereby control an oscillation amplitude.

Abstract: An oscillation control circuit comprising a PLL circuit and a phase-locked state discrimination circuit is adapted to an oscillation circuit that performs oscillation to produce an oscillation signal (CKX) when supply voltage is applied thereto. The PLL circuit produces a clock signal (CKP) whose frequency is a multiple of the frequency of the oscillation signal, wherein it controls the clock signal to be synchronized with the oscillation signal in phase. The phase-locked state discrimination circuit discriminates whether or not the PLL circuit is placed in a phase-locked state on the basis of a phase relationship between the oscillation signal and clock signal. Based on a discrimination result, a damping resistance adapted to the oscillation circuit is switched over. That is, the damping resistance (Rd) is reduced to cope with an unstable state of oscillation; then, it is restored to an original resistance thereof when oscillation is certainly stabilized.

Abstract: A method is provided for aligning the center frequency of an infrared transmitter. The method comprises the steps of: (a) providing a voltage-controlled oscillator for driving the infrared transmitter, where the oscillator is adapted to receive a bias voltage from a microprocessor; (b) applying a bias voltage to the oscillator; (c) receiving an output signal from the infrared transmitter into an infrared receiver; (d) determining a frequency associated with the output signal; and (e) adjusting the bias voltage based on the frequency associated with the output signal, thereby aligning the center frequency of the infrared transmitter.

Abstract: Method for accounting for factors (such as temperature) causing systematic errors (time-varying or constant) in a clock, such as a clock used in a ranging receiver (for use with a positioning system such as the Global Positioning System), and a corresponding clock system (including a clock and a filter such as a Kalman filter) for providing clock time and error, used for example in a ranging receiver. The invention adds new state vector components to account for systematic error. The process update equation used in the navigation solution is accordingly extended to include the additional components of the state vector.

Abstract: An oscillation stop detection circuit comprises delay means for delaying an oscillation signal having a predetermined cycle by a predetermined time to thereby output a delayed signal therefrom, detecting means for exclusive-ORing the oscillation signal and the delayed signal to thereby detect the presence of the oscillation signal and outputting a pulse signal in the predetermined cycle when the oscillation signal exists, and charge and discharge means having a capacitor electrically connected between an output node for outputting a detection signal indicative of whether the oscillation signal is at a stop and a source potential or a ground potential, and for discharging the capacitor when the pulse signal is supplied and charging the capacitor according to a predetermined time constant while the pulse signal is unsupplied.

Abstract: An improved oscillator test structure is disclosed. A structure according to one embodiment includes an odd plurality of first transistor pairs formed on a predetermined area of a semiconductor substrate. The transistor pairs are electrically connected in a serial ring. The structure also includes at least one second transistor pair, also formed within the predetermined area on the substrate, but electrically isolated from the odd plurality of first transistor pairs.

Abstract: A compact hand-held metal detector that detects small ferrous and non-ferrous metal objects, that has a detection pattern in three planes, and that includes a plurality of detection alarm indications including visual, audio, and tactile detection alarm indications is provided. The invention includes a single small detection coil combined with an electronic control circuit that permits the coil and associated electronic components to be mounted adjacent each other in a compact enclosure. The coil provides a spherical detection pattern that is active in all three planes which detects metal objects in any orientation with respect to the coil. Upon detection of a metal object, the detector provides a visual and audio or tactile alarm indication.

Abstract: A pump control system which can distinguish between water and oil so that a pump can be controlled to pump water and deactivated before oil is pumped. Sensing is accomplished by a pair of capacitive sensors, one located above the other in a vessel in which water accumulates. A dual mode frequency oscillator is associated with each sensor. Each sensor reacts to the dielectric constant of the liquid at the sensor by changing its capacitance, to thus detect the presence of a conductive substance, such as a liquid, to cause the sensor's oscillator to switch its mode of oscillation. The dual mode oscillator of each sensor selectively generates a control signal having two different duty cycles. As the dielectric constant of the liquid medium is sensed, a logic circuit interposed between the sensors allows the output of each sensor to be turned off when only the lower sensor is in water. The circuit turns on the pump only when both sensors are in water and the pump remains on until both sensors are out of water.

Abstract: A lock detection circuit for a phase lock loop circuit having a phase lock loop circuit, generally a series circuit of a detector, a filter and a VCO with a PLL input terminal and an output terminal. A test circuit is coupled to the phase lock loop and includes a signal generator responsive to the presence of an input signal on the input terminal to inject a test signal into the phase lock loop. The signal generator is preferably a low frequency oscillator wherein the term "low" is defined to mean any frequency from a few hertz up to gigahertz and generally a few kilohertz, as long as this frequency is at least about an order of magnitude less than the frequencies to be encountered at the RF input to the PLL. The signal generated by the signal generator is compared with the signal injected into the phase lock loop which is generally injected ahead of the loop filter.

Abstract: An electromagnetic wave generator for influencing different corporal states in a biological organism includes an oscillator circuit coupled to a microcontroller and an antenna coupled to the microcontroller through which waves at a given frequency are transmitted to a biological organism.

Abstract: A signal of a locking detector of a synthesizer indicates in a first state that a loop is locked, and in a second state that the loop is unlocked. The synthesizer may be temporarily deactivated by switching off the operating voltage of a voltage controlled oscillator by means of a switching signal. The alarm circuit of the synthesizer includes a first detector, a state of the output of which changes with a delay, in response to the change of the signal of the detector conveyed to the detector, and a second detector, the state of the output of which changes with a delay, in response to the change of the switching signal conveyed to the detector, and a device generating the alarm signal. The device provides the output signal of the alarm circuit in response to the output signals of the detectors. By selecting appropriate delay-times for the detector, it is possible to achieve the intended operation.

Abstract: In a semiconductor device having a CR oscillation circuit and a reset circuit, the semiconductor device includes a common terminal for constituting the CR oscillation circuit and the reset circuit. A voltage level at which the device falls into a reset state is lower than a low level voltage of an oscillation waveform and the device does not falls into the reset state during oscillation. As a result, the number of terminals of the device can be decreased to permit a larger number of functions to be included in a package having an equal number of pins, and the number of components externally equipped can be decreased to reduce expense of the components and management therefor.

Abstract: A shock detector for measuring intermittent shock events comprises a mechanical delay line to supply delayed output motion in response to input motion along an input axis. A transducer converts the delayed output motion to an electrical signal representative of the delayed output motion. The transducer is generally in a respective inactive state to reduce the power consumption of the shock detector. A relatively low power motion sensor, such as low power accelerometer or tilt actuated switch, is employed for switching the transducer to a respective active state in response to the input motion thereby allowing the shock detector to measure any intermittent shock event regardless of the generally inactive state of the transducer.

Abstract: A proximity detection system includes a dual mode oscillator for generating a pair of ON and OFF control signals. A sensing circuit including a capacitance device detects the presence of a conductive object, such as a liquid, to cause the oscillator to switch its modes of oscillation.

Abstract: A self-configurable clock circuit which automatically detects at power up whether an off-chip crystal oscillator is connected to an integrated circuit including the self-configurable clock circuit, and following such detection generates a system clock signal and a power on reset signal to be used by other circuitry included in the integrated circuit. If the off-chip crystal oscillator is connected to the integrated circuit, then the self-configurable clock circuit provides the system clock signal from a first signal generated from the off-chip crystal oscillator. On the other hand, if the off-chip crystal oscillator is not connected to the integrated circuit, then the self-configurable clock circuit provides the system clock signal from a second signal generated from an on-chip RC oscillator circuit.

Abstract: An alarm apparatus comprises an oscillator circuit (20) which provides an oscillating current to an antenna (A) from where a location (1) to be surveyed is irradiated with electromagnetic waves of in the RF frequency range provided by the oscillator circuit (20). The oscillator and the antenna are slightly mismatched with respect to their resonance frequency so as to avoid the oscillation current to go into resonance. Reception in the antenna (A) of an in-phase reflection of the emitted wave results in a superposition of the currents of the emitted and the received waves and increases thus the RF oscillation current. This current is coupled through a capacitor (C6) to a switch circuit (30) such as to trigger an alarm through actuation of the switch circuit if the RF current exceeds a defined threshold.

Abstract: An integrated circuit for detecting harmonic lock of a phase-locked loop includes a frequency synthesizer for receiving a reference clock signal and for generating an oscillator clock signal. A phase generator receives the oscillator clock signal and generates a phase of the oscillator clock signal. A shift register receives as an input the reference clock signal and is clocked by the phase of the oscillator clock signal to produce an output that is a repetitive sequence of logic states. In an alternate embodiment, a harmonic decode circuit decodes the shift register output to determine which harmonic the phase-locked loop has locked onto.

Abstract: An RF power-generator system for the frequency range of 2 to 30 MHz and a programmable sinusoidal power output of 0 to 1000 W. The system is constructed of modules (10, 30, 50, 70 and 90) accommodated in a shallow parallelepipedal housing (1) with a capacity of 4.6 l. The housing essentially comprises two lateral lengths (4) of structural section, a sheet-metal front (6), a sheet-metal bottom (5), and a lid. A crystal-controlled power-oscillator module (10) communicates by way of an RF line (121) with an intermediate module (30). The intermediate-amplifier module communicates by way of still another RF line (122) with a terminal power-amplifier module (50). The terminal power-amplifier module communicates by way of still another RF line (123) with a high-power filter (70). The filter communicates by way of still another RF line (124) with a high-power directional coupler (90). The RF power output can be intercepted at an RF plug (2).

Abstract: A radio transceiver including a PLL synthesizer and is adaptable to a TDMA system in which the frequency of a radio frequency carrier is switched frequently at high speed. When an unlock alarm of the PLL synthesizer is used as one of the device alarms, the unlock alarm to be generated in an initial unlock period which is usually provided every switching of an output frequency of the PLL synthesizer is not used as one of the device alarms. The prohibition of generation of this unlock alarm is started in synchronism with a frequency control signal supplied from a control portion of the radio transceiver to a frequency divider of the PLL synthesizer for switching the carrier frequency and is limited to an OFF period of the carrier transmitting/receiving period.

Abstract: An apparatus is provided for synchronously selecting different oscillators as the system clock source. The apparatus is comprised of two oscillator selectors. Each of the oscillator selectors has as its inputs the output of each of the oscillators and a three-bit command code which indicates which of the oscillators is to be selected by the oscillator selector and a single clock output. A different oscillator may be selected by each of the oscillator selectors at the same time. The output of the oscillator selectors are inputs to the clock controller. The clock controller also receives command signals for controlling the switching of the clock controller between the outputs of the two oscillator selectors. The output of the clock controller is the clock source for the system and a status signal indicating which oscillator selector is presently being used.

Abstract: A proximity detection system includes a dual mode oscillator for generating a pair of ON and OFF control signals. A sensing circuit including a capacitance device detects the presence of a conductive object, such as a liquid, to cause the oscillator to switch its modes of oscillation.

Abstract: A back-bias level sensor used for a semiconductor device wherein a sensing current for sensing a back-bias voltage is prevented from directly flowing into the substrate (or the back-bias voltage terminal). The gate of a PMOS transistor is provided with the back-bias voltage while the source is provided with a ground voltage, so that a pump circuit performs the pumping operation to increase the back-bias voltage when the back-bias voltage is lower than a predetermined voltage level; otherwise, the pump circuit is de-energized, thereby reducing the back-bias voltage.

Abstract: A method of detecting timing errors in a system oscillator for an electronic device, such as a power supply, includes the step of comparing a system oscillator signal with a delayed generated signal and generating a signal representative of the timing error when the system oscillator signal is not identical to the delayed signal. An LED indicates to an operator that a timing error has occurred. A hardware circuit implements the above-identified method.

Abstract: The station, in particular a terminal, comprises an oscillator (OS) having a feedback loop (1) and a station inductor element (L10) suitable for conferring a working frequency to the oscillator which varies relative to a rest frequency. The station also includes a station processor connected to the oscillator and capable of processing variations in the working frequency of the oscillator. The portable object, in particular a memory card, includes an electronic circuit which is switchable between an inactive state and an active state in which it sets up a resonant circuit tuned on a frequency which is distinct from the rest frequency while remaining suitable for being coupled inductively with the feedback loop (1) at the rest frequency. The portable object also includes an object processor capable of switching the electronic circuit as a function of the information to be transmitted to the station.

Abstract: An oscillation stoppage detecting circuit has a boost circuit to which is inputted an output of an oscillation circuit and a level detection circuit to which is inputted an output of the boost circuit. The boost circuit used here is, for example, a voltage doubler circuit which utilizes two diodes, a capacitor and an inverter, which is so-called a charge pump circuit. The boost circuit is operated by the oscillation output of the oscillation circuit and the oscillation stoppage is detected as a result of the comparison between the output voltage of the boost circuit and a threshold voltage of the level detection circuit. The arrangement enables to realize a circuit of low power consumption.

Abstract: A clock monitor circuit which is frequency-independent. The crystal terminals on a circuit being monitored for activity may be considered as an inverter combined with a phase delay. The innovative circuit has clock-output and clock-input terminals which are connected to the clock terminals on the circuit being monitored. When a rising edge appears on the clock-output terminal, the clock-input line is sampled: if the circuit being monitored is properly active, the level on the clock-input line will be high. Similarly, when a falling edge appears on the clock-output terminal, the clock-input line is sampled: if the circuit being monitored is properly active, the level on the clock-input line will be low. Whenever a low level is detected on a rising edge, or a high level on a falling edge, a counter chain will start counting down. The counter chain will be reset only when a high level is detected on a rising edge AND a low level is detected on the next falling edge.

Abstract: The station, in particular a terminal, comprises an oscillator (OS) having a feedback loop (1) and a station inductor element (L10) suitable for conferring a working frequency to the oscillator which varies relative to a rest frequency. The station also includes a station processor connected to the oscillator and capable of processing variations in the working frequency of the oscillator. The portable object, in particular a memory card, includes an electronic circuit which is switchable between an inactive state and an active state in which it sets up a resonant circuit tuned on a frequency which is distinct from the rest frequency while remaining suitable for being coupled inductively with the feedback loop (1) at the rest frequency. The portable object also includes an object processor capable of switching the electronic circuit as a function of the information to be transmitted to the station.

Abstract: A receiver is disclosed for acquiring and tracking a data signal in a highly stressed environment. The receiver comprises first and second I.F. sections, a mixer for translation from the first I.F. frequency to the second I.F. frequency, a 2 kHz bandpass filter at the second I.F. frequency, signal translator for synchronous translation of the signal at the second I.F. frequency to baseband, a digitizer for complex sampling operation on the baseband signal, a microprocessor for processing the digital samples, and a numerically controlled oscillator coupled to the mixer and controlled by the microprocessor. The microprocessor formulates matched digital discrete Fourier transform filters which drive frequency, phase and symbol lock loops at the symbol rate. Each of the loop filters is formed by symbol-rate recursive, first-order equations.

Abstract: An integrated circuit configuration and a method monitor an integrated oscillator in the circuit. The oscillator has a minimum frequency and furnishes a synchronously controlling clock rate for the functioning of the integrated circuit when excited by an external frequency standard. An integrated reserve oscillator has a maximum frequency below the minimum frequency of the oscillator. An integrated frequency comparator is connected to the reserve oscillator and to the oscillator for comparing the frequency of the reserve oscillator with the frequency of the oscillator.

Abstract: An environmental abnormality detection apparatus includes a detector for detecting environmental changes by monitoring physical changes in the environment and generating an output signal upon the detection of such an abnormality, a signal processor which generates an environmental abnormality signal based on the output of the detector, and a switching circuit connected between a pair of power source/signal lines. The apparatus further includes an oscillator and a control circuit which generates a signal for controlling the switching circuit obtained by the product of an output from the oscillator and the output of the signal processor. A power source is charged from the power source/signal lines, and supplies power to the detector, the signal processor and the oscillator.

Abstract: A detection system having sending units for sending data signals representative of a condition, such as fire, smoke, intrusion, battery condition, or an emergency, to a central receiving unit. The sending units include a microcomputer which generates a pseudo-random number, waits for a number of cycle periods equal to the pseudo-random number, then activates a transmitter to send a data signal to the receiving unit. The randomized transmission prevents the synchronized clashing of transmitters.

Abstract: A waterproof audible sound producing device for use by swimmers to adjust their stroke rate. A frequency control moves through a spectrum of frequencies on an incremental basis when a signal is received from a pressure sensitive signaling button. A slide switch allows the user to choose between at least two sets of frequencies and each set of frequencies contains less than five discrete frequencies and a zero output where there is no audible sound produced.