Digital non-linear pre-emphasis/de-emphasis apparatus

Claim 2

A digital non-linear pre-emphasis/de-emphasis appa­ratus fully satisfying the following equations: y n = b n · u n ┼ x n ; and u n = x n - x n-k ┼ a n-k · u n-k , where x n denotes an input signal at a time n; y n , a output signal; u n a parameter, a n and b n functions of u n ; and k, a positive integer.

Claim 3

A digital non-linear pre-emphasis/de-emphasis appa­ratus comprising: a high-pass filter means for obtaining a high frequency component signal u n of an input signal x n from the input signal x n from the input signal x n ; a first non-linear processing means for multiply­ing the signal u n by a coefficient a n which is a function of u n to obtain a feedback signal a n ·u n , the feedback signal being fed back to said high-pass filter means to vary a frequency band of said high-pass filter means; a second non-linear processing means for multiply­ing the signal u n by a coefficient b n which is a function of u n to obtain a signal b n ·u n ; and an operation means for mixing the input signal x n and the signal b n ·u n by a predetermined operation to obtain an output signal y n , wherein said apparatus satisfies, at a sampling timing n, the following condition; y n = b n ·u n + x n ; and u n = x n - x n-k + a n-k u n-k wherein k is a positive integer.

Claim 4

A digital non-linear pre-emphasis/de-emphasis appa­ratus comprising: a high-pass filter means for obtaining a high frequency component signal u n of an input signal x n from the input signal x n from the input signal x n ; a first non-linear processing means for multiply­ing the signal u n by a coefficient a n which is a function of u n to obtain a feedback signal a n ·u n , the feedback signal being fed back to said high-pass filter means to vary a frequency band of said high-pass filter means; a second non-linear processing means for multiply­ing the signal u n by a coefficient b n which is a function of u n to obtain a signal b n ·u n ; and an operation means for mixing the input signal x n and the signal b n ·u n by a predetermined operation to obtain an output signal y n , wherein said apparatus satisfies, at a sampling timing n, the following condition; y n = b n ·u n + x n ; and u n = x n - x n-k + a n-k u n-k wherein k is a positive integer.

Claim 6

An apparatus as in claim 2, wherein said high-pass filter means comprises: a subtraction means for subtracting the input signal x n from the feedback signal a n ·u n to obtain a signal a n ·u n - x n ; a delay means for delaying the signal a n ·u n - x n by k sampling period t obtain a delayed signal a n-k ·u n-k - x n-k ; and an addition means for adding the delayed signal a n-k ·u n-k - x n-k to the input signal x n to obtain the high frequency component signal u n = x n - x n-k + a n-k ·u n-k .

Claim 7

A digital non-linear pre-emphasis/de-emphasis ap­paratus comprising: a high-pass filter means for obtaining a high frequency component signal of an input signal from the input signal first and second non-linear processing means each for multiplying the high frequency component signal by a coefficient which is a function of the high frequency compo­nent signal; a first switching means for selecting one of out­puts of said first and second non-linear processing means to obtain a feedback signal which is fed back to said high-pass filter means to vary a frequency band of said high-pass filter means; third and fourth non-linear processing means each for multiplying the high frequency component signal by a coefficient which is a function of the high frequency compo­nent signal; a second switching means for selecting one of outputs of said third and fourth non-linear processing means; and an operation means for mixing the input signal and an output signal of said signal switching means to obtain an output signal, wherein said apparatus executes a non-linear pre-­emphasis process when said first and second switching means respectively select said first and third non-linear process­ing means, and a non-linear de-emphasis process when said first and second switching means respectively select said second and fourth non-linear processing means.

Claim 8

A digital non-linear pre-emphasis/de-emphasis ap­paratus comprising: a high-pass filter means for obtaining a high frequency component signal of an input signal from the input signal first and second non-linear processing means each for multiplying the high frequency component signal by a coefficient which is a function of the high frequency compo­nent signal; a first switching means for selecting one of out­puts of said first and second non-linear processing means to obtain a feedback signal which is fed back to said high-pass filter means to vary a frequency band of said high-pass filter means; third and fourth non-linear processing means each for multiplying the high frequency component signal by a coefficient which is a function of the high frequency compo­nent signal; a second switching means for selecting one of outputs of said third and fourth non-linear processing means; and an operation means for mixing the input signal and an output signal of said signal switching means to obtain an output signal, wherein said apparatus executes a non-linear pre-­emphasis process when said first and second switching means respectively select said first and third non-linear process­ing means, and a non-linear de-emphasis process when said first and second switching means respectively select said second and fourth non-linear processing means.

Claim 9

An apparatus as in claim 5, wherein, supposing that output signals of said first and third non-linear processing means are respectively a(u)·u and b(u)·u with respect to an input signal thereto u, where each of a(u) and b(u) is a function of u, and that output signals of said second and fourth non-linear processing means are respectively A(U)·U and B(U)·U with respect to an input signal thereto U, where each of A(U) and B(U) is a function of U, the following conditions are satisfied: U = (1 + b(u))·u, whereby said non-linear de-emphasis process has a reverse characteristic to that of said non-linear pre-emphasis pro­cess.

Claim 10

An apparatus as is claim 5, wherein said high-pass filter means comprises: a first delay means for delaying the input signal by a predetermined time to obtain a delayed input signal; a subtraction means for subtracting the delayed input signal from the input signal; a second delay means for delaying the feedback signal by the predetermined time to obtain a delayed feed­back signal; and an addition means for adding an output signal of said subtraction means and the delayed feedback signal to obtain the high frequency component signal.

Claim 11

An apparatus as in claim 5, wherein said high-pass filter means comprises: a subtraction means for subtracting the feedback signal from the input signal; a delay means for delaying an output signal of said subtraction means by a predetermined time; and an addition means for adding an output signal of said delay means and the input signal to obtain the high frequency component signal.

Claim 12

A digital non-linear pre-emphasis/de-emphasis appa­ratus comprising: a high-pass filter means for obtaining a high frequency component signal of an input signal; a first non-linear processing means for multiply­ing the high frequency component signal by a coefficient which is a function of the high frequency component signal to obtain a feedback signal which is fed back to said high-­pass filter means to vary a frequency band of said high-pass filter means; a second non-linear processing means for multiply­ing the high frequency component signal by a coefficient which is a function of the high frequency component signal; and an operation means for mixing an output signal of said second non-linear processing means and the input signal to obtain an output signal of said apparatus.

Claim 13

A digital non-linear pre-emphasis/de-emphasis appa­ratus comprising: a high-pass filter means for obtaining a high frequency component signal of an input signal; a first non-linear processing means for multiply­ing the high frequency component signal by a coefficient which is a function of the high frequency component signal to obtain a feedback signal which is fed back to said high-­pass filter means to vary a frequency band of said high-pass filter means; a second non-linear processing means for multiply­ing the high frequency component signal by a coefficient which is a function of the high frequency component signal; and an operation means for mixing an output signal of said second non-linear processing means and the input signal to obtain an output signal of said apparatus.

Claim 14

An apparatus as in claim 9, wherein said high-pass filter means comprises: a first delay means for delaying the input signal by a predetermined time to obtain a delayed input signal; a subtraction means for subtracting the delayed input signal from the input signal; a second delay means for delaying the feedback signal by the predetermined time to obtain a delayed feed­back signal; and an addition means for adding an output signal of said subtraction means and the delayed feedback signal to obtain the high frequency component signal.

Claim 15

An apparatus as in claim 9, wherein said high-pass filter means comprises: a subtraction means for subtracting the feedback signal from the input signal; a delay means for delaying an output signal of said subtraction means by a predetermined time; and an addition means for adding an output signal of said delay means and the input signal to obtain the high frequency component signal.