RF data communication link for wireless audible indication system

• US 5,680,102 A
• Filed: 07/29/1994
• Issued: 10/21/1997
• Est. Priority Date: 07/29/1994
• Status: Expired due to Term

• Current Assignee: Thomas & Betts International LLC (ABB Limited)
• Original Assignee: Dimango Products Corp (ABB Limited)
• Inventors: Xydis, Thomas G.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Pope, Daryl C.
• Application Number:
  US08/282,719
• Time in Patent Office: 1,180 Days
• Field of Search: 340/825.69, 340/825.72, 340/825.63, 341/176, 341/173, 341/174, 341/183, 455/139
• US Class Current: 340/539.16
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission

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.

Claims

1. A receiver for use in a wireless actuator system with a corresponding transmitter, the corresponding transmitter for transmitting a radio frequency signal, the receiver comprising:

a radio frequency detector which produces an intermediate signal upon receiving the radio frequency signal from the corresponding transmitter;

a demodulator, coupled to the radio frequency detector, which forms a discrete signal by comparing a first quantity to a second quantity, wherein the first quantity is representative of a behavior of the intermediate signal during a predefined first time interval and the second quantity is representative of a behavior of the intermediate signal during a predefined second time interval;

an actuator, coupled to the demodulator, which actuates a device in dependence upon the discrete signal;

wherein the demodulator rejects the radio frequency signal if the first quantity exceeds a first threshold and the second quantity exceeds a second threshold.

2. The receiver of claim 1 wherein the first quantity is representative of signal energy.

3. The receiver of claim 1 wherein the first time interval and the second time interval are nonoverlapping.

4. The receiver of claim 1 wherein the first time interval and the second time interval are each within a predetermined bit interval.

5. The receiver of claim 1 wherein the demodulator senses a stop signal when the first quantity is less than a first threshold and the second quantity is less than a second threshold.

15. The receiver of claim 1 wherein the actuator actuates a sound generator to generate an audible indication in dependence upon the discrete signal.

6. A receiver for use in an audible indication system with a corresponding transmitter, the corresponding transmitter for transmitting a radio frequency signal, the receiver comprising:

a radio frequency detector which produces an intermediate signal upon receiving the radio frequency signal from the corresponding transmitter;

a demodulator, coupled to the radio frequency detector, which forms a discrete signal by comparing a first quantity to a second quantity, wherein the first quantity is representative of an energy of the intermediate signal during a predefined first time interval and the second quantity is representative of an energy of the intermediate signal during a predefined second time interval, wherein the first time interval and the second time interval are nonoverlapping within a predetermined bit interval; and

a sound generator, coupled to the demodulator, which generates an audible indication in dependence upon the discrete signal;

wherein the demodulator rejects the radio frequency signal if the first quantity exceeds a first threshold and the second quantity exceeds a second threshold, and wherein the demodulator senses a stop signal when the first quantity is less than a third threshold and the second quantity is less than a fourth threshold.

7. A receiver for use in a wireless actuator system with a corresponding transmitter, the corresponding transmitter for transmitting a radio frequency signal, the receiver comprising:

a radio frequency detector which produces an intermediate signal upon receiving the radio frequency signal from the corresponding transmitter;

a demodulator, coupled to the radio frequency detector, which forms a discrete signal by comparing a first quantity to a second quantity, wherein the first quantity is representative of a behavior of the intermediate signal during a predefined first time interval and the second quantity is representative of a behavior of the intermediate signal during a predefined second time interval; and

an actuator, coupled to the demodulator, which actuates a device in dependence upon the discrete signal;

wherein the demodulator senses a stop signal when the first quantity is less than a first threshold and the second quantity is less than a second threshold.

8. The receiver of claim 7 wherein the first quantity is representative of signal energy.

9. The receiver of claim 7 wherein the first time interval and the second time interval are nonoverlapping.

10. The receiver of claim 7 wherein the first time interval and the second time interval are each within a predetermined bit interval.

11. The receiver of claim 7 wherein the demodulator rejects the radio frequency signal if the first quantity exceeds a first threshold and the second quantity exceeds a second threshold.

16. The receiver of claim 7 wherein the actuator actuates a sound generator to generate an audible indication in dependence upon the discrete signal.

12. A transmitter for use in an audible indication system, comprising:

a modulator for producing a first radio frequency signal in a first modulation format and for producing a second radio frequency signal in a second modulation format using a single carrier frequency; and

a format selector, coupled to the modulator, which allows a selection of at least one format of the first modulation format and the second modulation format;

wherein the transmitter communicates with at least one of a first corresponding receiver and a second corresponding receiver based upon the selection of the at least one format, wherein the first corresponding receiver produces an audible indication in response to receiving the first radio frequency signal, and wherein the second corresponding receiver is capable of producing an audible indication in response to receiving the second radio frequency signal.

13. The transmitter of claim 12 wherein the first modulation format includes a pulse position modulation of a plurality of bits.

14. The transmitter of claim 12 wherein the format selector includes at least one jumper wire, wherein the selection of the at least one format is modified by severing the at least one jumper wire.