Apparatus and method for measuring speaker transducer impedance versus frequency with ultralow inaudible signal
US11070179B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 2019 |
| Grant date | Jul 20, 2021 |
| Priority date | — |
| Expiry date | Sep 5, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45526
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An apparatus measures a speaker impedance. A DAC converts a known digital input signal to an audio frequency first analog voltage signal. Resistors with known resistance attenuate the first analog voltage signal to generate a current. The known resistance effectively determines the current because the known resistance is high relative to the speaker impedance. The current is sourced into the speaker to generate a second analog voltage signal. The known resistance is sufficiently high to cause the second analog voltage signal to be inaudible as transduced by the speaker. An amplifier amplifies the second analog voltage signal with a known gain to generate a third analog voltage signal. An ADC converts the third analog voltage signal to a digital output signal. A processing element calculates the impedance of the speaker proportional to the digital output signal based on the known digital input signal, the known resistance, and the known gain.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.