System and method for spectral shaping of dither signals
AssigneeBroadcom Corporation
InventorKevin Lee Miller
Life of this patent
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Abstract
An improved dither generation circuit and method for digital audio circuits uses a high-pass filter to reduce the energy contained in the audio band of the dither signal. The resulting dither signal is applied to the circuit in its main feedback loop and is effective to prevent idle tones. Because of its spectrally shaped characteristic this dither signal introduces less noise into the audio band of interest and thereby improves the overall signal-to-noise ratio of the audio circuit. In an embodiment, the dither signal is generated using pseudo-random numbers that are then interpreted as 2's complement numbers.
Claims20
A method for dithering in a digital signal processing circuit, comprising the steps of:
- (1) generating a series of numbers to produce a digital data stream representing a dither signal;
- (2) dithering signal values processed by the digital signal processing circuit using said digital data stream to provide dithered signal values;
- and
- (3) selecting one of a plurality of mappers to map said dithered signal values to respective digital sequences.
A method for digital dithering in a digital signal processing circuit, comprising the steps of:
- (1) generating a series of numbers;
- (2) high-pass filtering said series of numbers to generate a digital data stream representing a dither signal;
- (3) dithering signal values processed by the digital signal processing circuit using said digital data stream to provide dithered signal values;
- and
- (4) mapping said dithered signal values in a feedback of the digital signal processing circuit.
Dependencies are inferred from the claim text.