Patent ID: 9479865
Filing Date: 2016-10-25
CPC Classification: G06F,H03F,H03M,H04R

Claim Text:
1. A circuit system, comprising: an amplifier; a pair of sigma delta analog to digital converters (ΣΔ ADCs), including a first ΣΔ ADC and a second ΣΔ ADC, to generate a digitized amplifier signal, each having an input coupled to an output of the amplifier, each characterized by a quantization noise characteristic, wherein a quantization noise generated by the first ΣΔ ADC occurs in a first frequency band and a quantization noise generated by the second ΣΔ ADC occurs in a second frequency band different from the first; and a signal coder having inputs coupled to outputs of the first and second ΣΔ ADCs and configured to encode a signal output from the first ΣΔ ADC and a signal output from the second ΣΔ ADC into a single encoded data stream, wherein the signal coder includes a frequency transposing circuit configured to transpose ultrasonic frequency content of the signal output from the second ΣΔ ADC to an audible frequency range.