Rate convertor
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.
Claims19
A rate converter implemented in an audio processing circuit, the rate converter comprising:
- an input for receiving audio data sampled at an input sample rate;
- a sample index accumulator for determining a sample index for each output audio sample at an output sample rate different from the input sample rate;
- an error accumulator for determining and outputting an index error;
- a second order phase lock tracking loop for estimating a ratio between the input sample rate and the output sample rate;
- a gear controller configured to adjust gain values for application to the audio data during conversion between the first sample rate and the second sample rate, the adjusted gain values applied within the tracking loop based on the index error output of the error accumulator;
- and
- a sample interpolator configured to apply a continuous time filter with a predetermined frequency response to resample the audio data from the input sample rate to the output sample rate.
Dependencies are inferred from the claim text.