Flexible clocking for audio sample rate converter in a USB system
AssigneeMicrochip Technology Incorporated
InventorsYong Yuenyongsgool, Igor Wojewoda, Sergey Pavlov, Anton Alkhimenok, Kim Otten
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Abstract
A processor according to embodiments comprises an on-board sample rate converter for converting a source audio signal that is sampled at a first sampling rate to an output audio signal that is sampled at a second sampling rate. The sample rate converter utilizes a master clock signal in converting the audio signal. The sample rate converter selects the master clock signal from available reference clock signals, such as an on-chip system clock or a bus interface clock, and scales the frequency of the selected clock signal to generate the master clock signal with the frequency of the second sampling rate.
Claims20
A microcontroller comprising:
- an on-chip sample rate converter, wherein the sample rate converter receives a source audio signal that is sampled at a first sampling rate, and wherein the sample rate converter generates an output audio signal sampled at a second sampling rate, and wherein the sample rate converter utilizes a master clock signal in converting the sample rate of the audio signal, and
- a master clock circuit configured to generate the master clock signal wherein the master clock circuit selects from an on-chip system clock signal or a bus interface clock signal and scales the frequency of the selected clock signal to generate the master clock signal with the frequency of the second sampling rate.
A method for use in a processor, comprising:
- receiving a source audio signal wherein the source audio signal is sampled at a first sampling rate;
- receiving a first clock signal wherein the first clock signal is recovered from a digital signal;
- receiving a second clock signal wherein the second clock signal is generated by an RC oscillator circuit;
- selecting one of the first clock signal or the second clock signal;
- scaling the selected clock signal to generate a master clock signal with the frequency of a second sampling rate;
- converting the source audio signal that is sampled at a first sampling rate to an output audio signal sampled at the second sampling rate specified by the master clock signal.
A sample rate conversion system comprising:
- a sample rate converter wherein the sample rate converter receives a source audio signal that is sampled at a first sampling rate and wherein the sample rate converter generates an output audio signal sampled at a second sampling rate and wherein the sample rate converter utilizes a master clock signal in converting the audio signal;
- a clock recovery circuit configured to provide a first clock signal wherein the first clock signal is recovered from a digital signal;
- an RC oscillator circuit configured to provide a second clock signal;
- and
- a circuit configured to generate the master clock signal by selecting one of the first clock signal or the second clock signal and configured to scale the frequency of the selected clock signal to generate the master clock signal with the frequency of the second sampling rate.
Dependencies are inferred from the claim text.