Generating coefficients for a prediction filter in an encoder

• US 20010033616A1
• Filed: 01/05/2001
• Published: 10/25/2001
• Est. Priority Date: 01/07/2000
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Taori, Rakesh, Bruekers, Alphons Antonius Maria Lambertus, Rijnberg, Adriaan Johannes
• Granted Patent: US 7,224,747 B2
• Time in Patent Office: Days
• US Class Current: 375/232
• CPC Class Codes: H03H 21/0012 Digital adaptive filters

Abstract

A transmitter is disclosed for transmitting a transmission signal via a transmission medium. The transmitter derives a prediction signal from the digital information signal in dependence on an array of prediction filter coefficients. The array of prediction filler coefficients is obtained by smoothing a first array of coefficients. Said first array of coefficients is generated in response to the digital information signal. A residual signal is obtained by combination of the digital information signal and the prediction signal. The residual signal is encoded so as to obtain an encoded signal. The encoded signal is transmitted via the transmission medium.

Claims

1. A transmitting device for transmitting a digital information signal via a transmission medium, including:

input means for receiving the digital information signal,

adaptive prediction filter means adapted to derive a prediction signal from the digital information signal in dependence on an array of prediction filter coefficients,

first signal combination means for combining the digital information signal and said prediction signal so as to obtain a residual signal,

encoding means for encoding said residual signal so as to obtain an encoded signal,

coefficient generator means for generating an array of filter coefficients A[i] in response to the digital information signal, i being an integer for which it holds that 0<

i<

p, where p is a variable,

output means for supplying the encoded signal to an output terminal for transmission via a transmission medium, characterized in that the device further comprises

smoothing means for smoothing the array of filter coefficients A[i] so as to obtain the array of prediction filter coefficients for supply to the adaptive prediction filter means.

2. A transmitting device as claimed in

claim 1

, characterized in that the smoothing means comprises low-pass filtering means for low-pass filtering the coefficients so as to obtain the coefficient signal.

3. A transmitting device as claimed in

claim 2

, characterized in that the low-pass filtering means are in the form of a FIR filter.

4. A transmitting device as claimed in

claim 2

, characterized in that the low-pass Filtering means are in the form of an IIR filter.

5. A transmitting device as claimed in

claim 2

, characterized in that the filtering means is adapted to perform the following equations to obtain the coefficients:

C_out[0]=C_in[0], C_out[i]=0.25*C_in[i+1]+0.5*C_in[i]+0.25*C_out[i−

1], whereby i is an integer and 1<

i<

n−

2, C_out[n−

1]=C_in[n−

1],

C_in[x] being coefficient number x before smoothing. C_out[x] being coefficient number x after smoothing.

6. A transmitting device as claimed in any one of the preceding claims, in the form of an arrangement for writing the encoded signal on a record carrier.

7. A method of transmitting a digital information signal via a transmission medium, comprising the steps of

receiving the digital information signal,

deriving a prediction signal from the digital information signal in dependence on an array of prediction filter coefficients,

combining the digital information signal and said prediction signal so as to obtain a residual signal,

encoding said residual signal so as to obtain an encoded signal,

generating an array of filter coefficients A[i] in response to the digital information signal, i being an integer for which it holds that 0<

i<

p, where p is a variable,

supplying the encoded signal to an output terminal for transmission via a transmission medium, characterized in that the method further comprises the step of

smoothing the array of filter coefficients A[i] so as to obtain the array of prediction filter coefficients.

8. A receiver for receiving a transmission signal and generating a digital information signal therefrom, the receiver comprising:

receiving means for receiving the transmission signal and retrieving an encoded signal therefrom,

decoding means for decoding the encoded signal so as to obtain a residual signal,

adaptive prediction filter means adapted to derive a prediction signal from the digital information signal in dependence on an array of prediction filter coefficients,

signal combination means for combining the residual signal and the prediction signal so as to obtain the digital information signal,

coefficient generator means for generating an array of filter coefficients A[i] in response to the digital information signal, i being an integer for which it holds that 0<

i<

p, where p is a variable, characterized in that the receiving device further comprises

smoothing means for smoothing the array of filter coefficients A[i] so as to obtain the array of prediction filter coefficients for supply to the adaptive prediction filter means.