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AssigneeApple Inc.
InventorsTimothy M. Johnson, Lawrence F. Heyl, Wendell B. Sander, Douglas M. Farrar
Estimating the term…
An audio host device has an electrical interface having a speaker contact, a microphone contact, and a reference contact. The reference contact is shared by a microphone and a speaker. The reference contact is also directly coupled to a power return plane of the audio host device. A difference amplifier is provided, having a cold input and a hot input. The hot input is coupled to the microphone contact. A switched attenuator circuit is also provided that has first and second states. In the first state, the attenuator circuit couples a sense point of the reference contact to the cold input, while in the second state the cold input is isolated from the reference sense point. Other embodiments are also described and claimed.
An audio host device comprising:
A method for operating an audio host device having an electrical interface to a microphone-speaker combination, the electrical interface having a microphone contact, a speaker contact, and a power return contact, the method, comprising:
A portable audio host device comprising:
The portable audio host device of claim further comprising:
Dependencies are inferred from the claim text.