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US 7,088,779 B2Granted
Method and apparatus for reducing the word length of a digital input signal and method and apparatus for recovering a digital input signal
AssigneeKoninklijke Philips Electronics N.V.
InventorRonaldus Maria Aarts
Life of this patent
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Abstract
A method and signal processing apparatus for reducing the number of bits of a digital input signal (Mi), includes adding a pseudo-random noise signal (Na) to the digital input signal (Mi) to obtain an intermediate signal (Di), the pseudo-random noise signal (Na) being defined by noise parameters (Np), and quantizing the intermediate signal (Di), having a word length of n bits, to a reduced word-length signal (Me) having a word length of m bits, n being larger than or equal to m. The method further includes quantizing the intermediate signal (Di) using a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters (NLDp).
Claims6
A method for reducing the number of bits of a digital input signal, said method comprising the steps of:
- adding a pseudo-random noise signal to the digital input signal to form an intermediate signal, the pseudo-random noise signal being defined by noise parameters;
- and
- quantizing the intermediate signal having a word length of n bits to a reduced word-length signal having a word length of m bits, where n and m are integers, n being larger than or equal to m, the quantizing of the intermediate signal including a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters, a quantization step of the first transfer function for small amplitudes being smaller than a quantization step for large amplitudes,
- wherein the gain of the first transfer function is substantially equal to one for small amplitudes, and wherein the gain decreases for large amplitudes,
- and wherein the first transfer function equals:
- Me/Di=c1 tan h(c2Di+c3),
- in which Me is the reduced word-length signal, Di is the intermediate signal, and c1, c2, c3 are the non-linear device parameters.
4 more elements
A method for generating and recording on a recording medium encoded signals from a digital input signal, said method comprising the steps of:
- adding a pseudo-random noise signal to the digital input signal to form an intermediate signal, the pseudo-random noise signal being defined by noise parameters;
- and
- quantizing the intermediate signal having a word length of n bits to a reduced word-length signal having a word length of m bits, where n and m are integers, n being larger than or equal to m, the quantizing of the intermediate signal including a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters, wherein said method further comprises the step of:
- recording the reduced word-length signal, the non-linear device parameters and the noise parameters as the encoded signals on a recording medium,
- in which the recording medium is a compact disc and the reduced word-length signal is recorded on a first channel, and the non-linear device parameters and the noise parameters are recorded on a second channel, the first channel and second channel being separate channels.
2 more elements
A method for generating and recording on a recording medium encoded signals from a digital input signal, said method comprising the steps of:
- adding a pseudo-random noise signal to the digital input signal to form an intermediate signal, the pseudo-random noise signal being defined by noise parameters;
- and
- quantizing the intermediate signal having a word length of n bits to a reduced word-length signal having a word length of m bits, where n and m are integers, n being larger than or equal to m, the quantizing of the intermediate signal including a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters,
- wherein said method further comprises the steps of:
- forming a difference signal, the difference signal being equal to the intermediate signal minus the reduced word-length signal;
- and
- recording the difference signal, the non-linear device parameters and the noise parameters as the encoded signals on a recording medium.
4 more elements
A signal processing apparatus comprising:
- a pseudo-random noise generator for generating a noise signal defined by noise parameters;
- an addition element connected to the pseudo-random noise generator for adding the noise signal to a digital input signal thereby forming an intermediate signal;
- and
- a first quantizing element connected to the addition element for transforming the intermediate signal, having a word length of n bits into a reduced word-length signal having a word length of m bits, n and m being integers and n being larger than or equal to m, wherein,
- the quantizing element has a non-linear transfer function, the non-linear transfer function being defined by non-linear device parameters, wherein
- a quantization step of the non-linear transfer function for small amplitudes being smaller than a quantization step for large amplitudes, the gain of the non-linear transfer function being substantially equal to one for small amplitudes, and the gain decreasing for large amplitudes, and wherein
- the non-linear transfer function equals:
- Me/Di=c1 tan h(c2Di+c3),
- in which Me is the reduced word-length signal, Di is the intermediate signal, and c1, c2, c3 are the non-linear device parameters.
6 more elements
A signal processing apparatus comprising:
- means for adding a pseudo-random noise signal to a digital input signal to obtain an intermediate signal, the pseudo-random noise signal being defined by noise parameters;
- and
- means for quantizing the intermediate signal, having a word length of n bits, to a reduced word-length signal having a word length of m bits, n and m being integers and n being larger than or equal to m, wherein
- the quantizing means includes a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters, wherein
- a quantization step of the first transfer function for small amplitudes being smaller than a quantization step for large amplitudes, the gain of the first transfer function being substantially equal to one for small amplitudes, and wherein the gain decreases for large amplitudes, and wherein
- the first transfer function equals:
- Me/Di=c1 tan h(c2Di+c3),
- in which Me is the reduced word-length signal, Di is the intermediate signal, and c1, c2, c3 are the non-linear device parameters.
5 more elements
Dependencies are inferred from the claim text.