Self-powered digital audio devices
An integrated speaker or microphone derives its power from an incoming signal, thereby minimizing or eliminating the need for an external amplifier or power supply. A system according to the invention includes an audio transducer, an input for receiving a digital audio signal, an amplifier for amplifying the digital audio signal to or from the audio transducer, and a rectifier for rectifying the digital audio signal for use in powering the amplifier. A filter may be included for filtering the output of the rectifier. In the preferred embodiment, the digital audio signal uses a non-return-to-zero (NRZ) encoding scheme. When the transducer is a microphone, it is connected to an analog-to-digital (A/D) converter, also powered by the rectified digital audio signal.
1 . A self-powered digital audio system, comprising:
an audio transducer;
an input for receiving a digital audio signal;
an amplifier for amplifying the digital audio signal to or from the audio transducer; and
a rectifier for rectifying the digital audio signal for use in powering the amplifier.
2 . The self-powered digital audio system of claim 1 , wherein the digital audio signal uses a non-return-to-zero (NRZ) encoding scheme.
3 . The self-powered digital audio system of claim 1 , further including a filter for filtering the output of the rectifier.
4 . The self-powered digital audio device of claim 1 , wherein:
the transducer is a microphone; and
the microphone is connected to an analog-to-digital (A/D) converter also powered by the rectified digital audio signal.
5 . The self-powered digital audio device of claim 1 , wherein the transducer is a speaker.