US 6,661,360 B2 · Analog to digital converter that services voice communications

Abstract

An Analog-to-Digital-Converter (ADC) converts an analog signal to digital data. The ADC includes a modulator, a decimation filter, and a time dither clock reduction circuit. The modulator receives the analog signal and a feedback signal and, based there upon, produces a modulated signal at a modulator clock rate. The decimation filter couples to the modulator, receives the modulated signal, and decimates and filters the modulated signal to produce the digital data. The time dither clock reduction circuit receives the modulated signal and provides the feedback signal to the modulator. The time dither clock reduction circuit applies both clock reduction and time dithering to the modulated signal to produce the feedback signal. At each modulator clock cycle, the time dithering clock reduction circuit considers modulated signals for a dithering factor, N, previous modulator clock cycles and a modulated signal for a current modulator clock cycle. If at least one constraint is satisfied for the N previous modulator clock cycles, the time dithering clock reduction circuit is allowed to transition the feedback signal with the modulated signal. If not, the time dithering clock reduction circuit holds the prior value of the feedback signal. After a transition, a new dithering factor may be determined. The ADC may be contained in a wireless local area network (WLAN) transceiving integrated circuit that services voice communications in a WLAN with at least one other WLAN device.

Claims34

Dependent claims

An Analog-to-Digital-Converter (ADC) that receives an analog signal and that converts the analog signal to digital data, the ADC comprising:

a modulator that receives the analog signal and a feedback signal, wherein the modulator modulates the analog signal to produce a modulated signal at a modulator clock rate;
a decimation filter coupled to the modulator to receive the modulated signal, wherein the decimation filter decimates and filters the modulated signal to produce the digital data;
and
a time dither clock reduction circuit that receives the modulated signal and that provides the feedback signal to the modulator, wherein the time dither clock reduction circuit applies both clock reduction and time dithering to the modulated signal to produce the feedback signal.

1 more element

A Wireless Local Area Network (WLAN) transceiving integrated circuit that services voice communications in a WLAN with at least one WLAN device, the WLAN transceiving integrated circuit comprising:

a WLAN interface that wirelessly communicates with the at least one WLAN device to receive inbound packetized audio data from the at least one WLAN device and to transmit outbound packetized audio data to the at least one WLAN device;
a transcoder operably coupled to the WLAN interface, wherein the transcoder receives the inbound packetized audio data and converts the inbound packetized audio data to inbound Pulse Code Modulated (PCM) WLAN audio data, and wherein the transcoder receives outbound PCM WLAN audio data and converts the outbound PCM WLAN audio data to the outbound packetized audio data;
and
an audio coder/decoder operably coupled to the transcoder that produces the outbound PCM WLAN audio data, the coder/decoder including an analog to digital converter that receives an analog audio signal and that converts the analog audio signal to PCM WLAN audio data, the analog to digital converter including:
a modulator that receives the analog audio signal and a feedback signal, wherein the modulator modulates the analog audio signal to produce a modulated signal at a modulator clock rate;
a decimation filter coupled to the modulator to receive the modulated signal, wherein the decimation filter decimates and filters the modulated signal to produce the PCM WLAN audio data;
and
a time dither clock reduction circuit that receives the modulated signal and that provides the feedback signal to the modulator, wherein the time dither clock reduction circuit applies both clock reduction and time dithering to the modulated signal to produce the feedback signal.

5 more elements

Dependencies are inferred from the claim text.

Analog to digital converter that services voice communications

Life of this patent

Analog to digital converter that services voice communications

Life of this patent

Abstract

Claims34