Telecoil hum filter
AssigneeEtymotic Research, Inc.
InventorStephen D. Julstrom
Life of this patent
Estimating the term…
Abstract
A system and/or method is provided for enhanced listening of audio signals acquired via a telecoil by performing hum filtering. The system may include a telecoil and a telecoil hum filter. The telecoil hum filter may include a comb notch filter. The comb notch filter may include a delay module and a comb notch filter summing module. The telecoil may be operable to receive a magnetic signal and convert the magnetic signal to an input audio signal. The delay module of the comb notch filter may be configured to generate a delayed signal by applying a delay to the input audio signal. The delay may be based on a fundamental hum frequency. The comb notch filter summing module may be configured to generate a comb notch filter output signal by adding the input audio signal and the delay signal.
Claims23
A system comprising:
- a telecoil operable to receive a magnetic signal and convert the magnetic signal to an input audio signal;
- and
- a telecoil hum filter comprising:
- a comb notch filter configured to provide attenuation notches at odd harmonic frequencies in the input audio signal below a cutoff frequency, the comb notch filter comprising:
- a delay module and a low pass filter configured to generate a filtered delayed signal by filtering and applying a delay to the input audio signal, wherein the delay is equal to:
- 1
- 2
- *
- freq
- where freq is the fundamental hum frequency, and
- a comb notch filter summing module configured to generate a comb notch filter output signal by adding the input audio signal and the filtered delayed signal.
A method comprising:
- receiving a magnetic signal at a telecoil;
- converting the magnetic signal to an input audio signal at the telecoil;
- generating a filtered delayed signal at a low-pass filter and a delay module of a comb notch filter by providing attenuation notches at odd harmonic frequencies in the input audio signal below a cutoff frequency, wherein the filtered delayed signal is generated by filtering and applying a delay to the input audio signal, wherein the delay is equal to:
- 1
- 2
- *
- freq
- where freq is the fundamental hum frequency, and
- generating a comb notch filter output signal at a comb notch filter summing module by adding the input audio signal and the filtered delayed signal.
A non-transitory computer readable medium having stored thereon, a computer program having at least one code section, the at least one code section being executable by a machine for causing the machine to perform steps comprising:
- receiving an input audio signal from a telecoil;
- generating a filtered delayed signal at a low-pass filter and a delay module of a comb notch filter by providing attenuation notches at odd harmonic frequencies in the input audio signal below a cutoff frequency, wherein the filtered delayed signal is generated by filtering and applying a delay to the input audio signal, wherein the delay is equal to:
- 1
- 2
- *
- freq
- where freq is the fundamental hum frequency;
- and
- generating a comb notch filter output signal at a comb notch filter summing module by adding the input audio signal and the filtered delayed signal.
Dependencies are inferred from the claim text.