Audio amplifier switching noise measuring method and device
AssigneeSGS-Thomson Microelectronics S.A.
InventorsAndrea Fassina, Giovanni Avenia, Elia Pagani
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Abstract
A method and device for measuring the switching noise of an audio amplifier by measuring the energy of the noise signal at the output of the audio amplifier as the amplifier is switched from one operating condition to another by a control signal, and after first weighing the energy according to the frequency and volume sensitivity of the human ear. The device comprises a control signal generator; an audio band filter connected to the output of the audio amplifier; a meter for measuring the power of the filtered signal; and an integrating element for calculating the energy of the filtered signal.
Claims36
A method of measuring switching noise of an audio amplifier, comprising the steps of:
- switching said audio amplifier between at least two different operational states which generates a noise signal at an output of the audio amplifier;
- filtering said noise signal to obtain an audio band signal;
- and
- determining a value of energy contained in said audio band signal.
A device for measuring switching noise of an audio amplifier having a signal input, a control input and an output;
- the device comprising:
- switching control means for switching said audio amplifier between different at least two operational states which generates a noise signal at said output of said audio amplifier;
- filter means for filtering said noise signal to obtain an audio band signal;
- and
- energy determining means for determining a value of energy of said audio band signal.
A device for measuring switching noise of an audio amplifier having a signal input, a control input, and an output, the device comprising:
- an audio filter having an input coupled to the output of the amplifier to receive a noise signal and an output that provides an audio band signal the audio band signal being generated by audio band filtering the noise signal;
- and
- an integrator having an input coupled to the output of the filter to receive the audio band signal and an output that provides a signal corresponding to a value of energy contained within the audio band signal.
An automatic test unit for measuring switching noise of an audio amplifier, the amplifier having a first input, a control input, and an output, the unit comprising:
- a filter having an input coupled to the output of the amplifier that receives a noise signal from the amplifier and an output that provides a filtered signal, the filtered signal being generated by audio band filtering the noise signal;
- an integrator circuit having an input coupled to the output of the filter to receive the filtered signal and an output that provides an energy signal corresponding to a value of energy contained within the filtered signal.
Dependencies are inferred from the claim text.