Device with precision frequency stabilized audible alarm circuit

Patent metadata

Field	Value
Publication number	US-10121333-B2
Application number	US-201715727059-A
Country	US
Kind code	B2
Filing date	Oct 6, 2017
Priority date	Dec 30, 2015
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

Systems for ensuring an audible alarm circuit sounds at a minimum magnitude of loudness are provided. Different circuitry embodiments discussed herein are each capable of assisting the audible alarm circuit in maintaining a minimum loudness threshold. Audible alarm circuit operation optimization can be achieved using embodiments that fall within anyone of four general categories: compensation networks, direct drive, dynamic tuning, and microphone feedback based dynamic tuning. Use of such circuitry can increase production yields by compensating for manufacturing variations of alarm components and aging characteristics of the components.

First claim

What is claimed is:

1. A device comprising:
an electroacoustic transducer;
driver circuitry coupled to the transducer, the driver circuitry operative to drive operation of the transducer;
control circuitry coupled to the driver circuitry, the control circuitry operative to provide a signal that can vary output of the driver circuitry;
a microphone;
sense circuitry coupled to the control circuitry and the microphone, the sense circuitry operative to:
monitor an output of the microphone; and
instruct the control circuitry to change a value of its adjustable network based on the monitored output of the microphone such that the transducer emits an audio signal having at least a minimum magnitude, wherein the transducer is coupled to the control circuitry, and wherein the sense circuitry permanently configures the adjustable network to be used as a phase shift network that supplements a phase of the transducer to enable stable operation of the transducer.

2. The device of claim 1 , wherein the sense circuitry instructs the control circuitry in real-time.

3. The device of claim 1 , wherein the control circuitry comprises an adjustable network that can vary output of the driver circuitry, and wherein the sense circuitry instructs the control circuitry to change a value of its adjustable network based on the monitored output of the microphone such that the transducer emits an audio signal having a maximum magnitude.

4. The device of claim 1 , wherein the value is changed such that the stable operation of the transducer at the at least the minimum magnitude occurs at a resonant frequency of about 520 Hz.

5. The device of claim 1 , wherein the value is changed such that the stable operation of the transducer at the at least the minimum magnitude occurs at a resonant frequency of about 3 kHz.

Assignees

• Google Inc
• Google Llc

Inventors

• Warren Daniel Adam
• Heyl Lawrence Frederick
• Ho Dietrich
• Aina Morakinyo John
• Smith Ian C
• Saperstein William
• Vadathavoor Bhaskar

Classifications

• G08B3/10 Primary

  using electric transmission; using electromagnetic transmission · CPC title

• H04R17/00

  Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) · CPC title

• G08B29/18

  Prevention or correction of operating errors (G08B29/02, G08B29/12 take precedence) · CPC title

• H04R3/00

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title

• H04R2430/01

  Aspects of volume control, not necessarily automatic, in sound systems · CPC title