Rate converter
AssigneeAvnera Corporation
InventorXudong Zhao
Life of this patent
Estimating the term…
Abstract
Embodiments of the invention may be used to implement a rate converter that includes: 6 channels in forward (audio) path, each channel having a 24-bit signal path per channel, an End-to-end SNR of 110 dB, all within the 20 Hz to 20 KHz bandwidth. Embodiment may also be used to implement a rate converter having: 2 channels in a reverse path, such as for voice signals, 16-bit signal path per channel, an End-to-end SNR of 93 dB, all within 20 Hz to 20 KHz bandwidth. The rate converter may include sample rates such as 8, 11.025, 12, 16, 22.05, 24, 32 44.1, 48, and 96 KHz. Further, rate converters according to embodiments may include a gated clock in low-power mode to conserve power.
Claims20
An audio processing circuit, comprising:
- a multiplier accumulator having a multiplier and an adder, the multiplier accumulator configured to output an output sample;
- a first multiplexer configured to receive a sample index and a sample input and output one of the sample index and the sample output to the multiplier of the multiplier accumulator;
- a second multiplexer configured to receive a coefficient and the output sample and output one of the coefficient and the output sample to the multiplier;
- an output accumulator configured to receive and store the output sample;
- and
- a third multiplexer configured to receive the output sample from the output accumulator and the coefficient and output one of the coefficient and output sampler to the adder.
A method for converting an input sample having an input sample rate to an output sample having an output sample rate, comprising:
- selecting one of a sample index or a sample input to output to a multiplier;
- selecting one of a coefficient or an output of an adder to output to the multiplier;
- multiplying at a multiplier the selected one of the input sample or the sample index with the selected one of the coefficient or the output of an adder to generate a multiplier output;
- selecting one of the coefficient or an output from an output accumulator to output to the adder;
- adding the selected one of the output from the output accumulator or the coefficient with the output of the multiplier to generate an output sample;
- and
- storing the output sample in the output accumulator.
A method for converting an input sample having an input sample rate to an output sample having an output sample rate, comprising:
- determining an index error;
- adjusting gain values based on the index error;
- generating a sample index based on the gain values;
- multiplying at a multiplier one of the input sample or the sample index with one of a coefficient or an output of an adder to generate a multiplier output;
- selecting one of the coefficient or an output from an output accumulator to output to the adder;
- adding the selected one of the output from the output accumulator or the coefficient with the output of the multiplier to generate an output sample;
- and
- storing the output sample in the output accumulator.
Dependencies are inferred from the claim text.