Patent ID: 9094761
Filing Date: 2015-07-28
Classification: H04R

Abstract:
1. A method for modulating an infrared headphone interface signal, comprising the steps of: providing a first audio signal having an analog audio value; providing a memory having a plurality of locations and containing digital phase offset values; providing a dock signal having a dock frequency; providing a second audio signal having a center carrier frequency that deviates with the analog audio value of the first audio signal; determining an instantaneous value of the center carrier frequency; dividing the dock frequency by the instantaneous carrier frequency value to thereby calculate a number of samples per cycle; dividing a number of location addresses in the memory by the number of samples per cycle to thereby calculate a memory access interval; accessing the memory at location addresses separated by the calculated memory access interval; and using the digital phase offset values at the accessed memory location addresses to reproduce the first audio signal by use of headphones.