Wireless audible indication system with low power signal processing
First Claim
1. A receiver for use in an audible indication system with a corresponding transmitter capable of transmitting a radio frequency signal, the receiver comprising:
- a radio frequency detector which produces a first intermediate signal upon receiving the radio frequency signal from the corresponding transmitter;
a signal processing circuit, coupled to the radio frequency detector, which produces a second intermediate signal in dependence upon the first intermediate signal, the signal processing circuit having a series of one or more cascaded stages which includes a peak detector stage; and
a sound generator, coupled to the signal processing circuit, which generates an audible indication in dependence upon the second intermediate signal;
wherein the peak detector stage includes a transistor having an emitter, a collector, and a base, wherein the emitter is coupled to a first supply voltage by a parallel combination of a resistor and a capacitor, wherein the collector is coupled to a second supply voltage, and wherein the peak detector stage is operative to peak detect a signal applied at the base to produce a peak detected signal at the emitter.
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Accused Products
Abstract
A wireless audible indication system comprising a transmitter and a receiver. An embodiment of the transmitter includes a modulator formed by a microprocessor and a radio frequency oscillator. The modulation format employed is selectable by the user using severable jumper wires. A battery status circuit is included which verifies the status of a battery within the transmitter. The modulator transmits a low battery bit to the receiver in order to alert the user of a weak transmitter battery. An embodiment of the receiver includes a superregenerative detector which produces an intermediate signal upon receiving a radio frequency signal. A signal processing circuit, which includes an active peak detector stage and a discrete comparator stage, is used to process the intermediate signal. A microprocessor controls a sound generator circuit in response to the processed intermediate signal. The microprocessor, which normally operates in an inactive mode, is awaken using a wake-up circuit upon reception of the radio frequency signal. A battery status circuit is included to verify the status of a battery within the receiver. Embodiments of the transmitter and receiver employ a pulse position modulation scheme.
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Citations
12 Claims
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1. A receiver for use in an audible indication system with a corresponding transmitter capable of transmitting a radio frequency signal, the receiver comprising:
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a radio frequency detector which produces a first intermediate signal upon receiving the radio frequency signal from the corresponding transmitter; a signal processing circuit, coupled to the radio frequency detector, which produces a second intermediate signal in dependence upon the first intermediate signal, the signal processing circuit having a series of one or more cascaded stages which includes a peak detector stage; and a sound generator, coupled to the signal processing circuit, which generates an audible indication in dependence upon the second intermediate signal; wherein the peak detector stage includes a transistor having an emitter, a collector, and a base, wherein the emitter is coupled to a first supply voltage by a parallel combination of a resistor and a capacitor, wherein the collector is coupled to a second supply voltage, and wherein the peak detector stage is operative to peak detect a signal applied at the base to produce a peak detected signal at the emitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A receiver for use in an audible indication system with a corresponding transmitter capable of transmitting a radio frequency signal, the receiver comprising:
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a radio frequency detector which produces a first intermediate signal upon receiving the radio frequency signal from the corresponding transmitter; a signal processing circuit, coupled to the radio frequency detector, which produces a second intermediate signal in dependence upon the first intermediate signal, the signal processing circuit having a series of one or more cascaded stages which includes a comparator stage; and a sound generator, coupled to the signal processing circuit, which generates an audible indication in dependence upon the second intermediate signal; wherein the comparator stage includes a differential amplifier formed using two transistors from an integrated transistor array, the two transistors including a first transistor having a base which receives a pulsed signal containing a plurality of pulses, and a second transistor having a base which receives a fixed voltage level, wherein the comparator stage is operative to detect the plurality of pulses by comparing the pulsed signal to the fixed voltage level. - View Dependent Claims (11, 12)
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Specification