US4941177A — Variable matrix decoder

Claim 1

Independent Claim 185 words

A decoder for decoding two or more channel signals in a directional information system wherein at least four input signals containing directional information are encoded into the two or more channel signals, said decoder comprising: first means for generating at least a first dominance signal indicative of the ratio of the amplitudes of a pair of the channel signals; second means for generating at least a second dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and matrix means responsive to said two or more channel signals and to said at least two dominance signals for generating a plurality of output signals for which directional effects of the output signals are enhanced, wherein the first dominance signal D LR and the second dominance signal D CS are given by: ##EQU11## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a, k are constants; wherein said matrix means includes means for deriving three directional control signals E L , E R and E C .

Claim 2

Dependent Claim 185 words

A decoder for decoding two or more channel signals in a directional information system wherein at least four input signals containing directional information are encoded into the two or more channel signals, said decoder comprising: first means for generating at least a first dominance signal indicative of the ratio of the amplitudes of a pair of the channel signals; second means for generating at least a second dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and matrix means responsive to said two or more channel signals and to said at least two dominance signals for generating a plurality of output signals for which directional effects of the output signals are enhanced, wherein the first dominance signal D LR and the second dominance signal D CS are given by: ##EQU11## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a, k are constants; wherein said matrix means includes means for deriving three directional control signals E L , E R and E C .

Claim 3

Dependent Claim 34 words

The decoder of claim 1, wherein said means for deriving three directional control signals E L , E R , E C derives the three directional control signals according to the following equations: ##EQU12##

Claim 4

Dependent Claim 93 words

The decoder of claim 2, wherein the matrix means generates the three outputs signals L', R', C', so that the three output signals are defined by means of the equations below: ##EQU13## where V is a 1 by 4 matrix; G L , G R , G C , are 4 by 2 matrices of predetermined coefficients; b is a constant and F L , F R , R C , are given by: F L =a b .E L F R =a b .E R F C =a b .E C .

Claim 5

Dependent Claim 13 words

The decoder of claim 3, wherein the value of b is about 0.839.

Claim 6

Dependent Claim 20 words

The decoder of claim 3, wherein the G L , G R , G C matrices are as follows: ##EQU14##

Claim 7

Dependent Claim 38 words

The decoder of claim 3, wherein the G L , G R , G C matrices are derived from four equations Q×G L =H L , Q×G R =H R , Q×G C =H C , where ##EQU15##

Claim 8

Dependent Claim 65 words

The decoder of claim 3, wherein the matrix means further comprises: means for generating 6 product signals wherein each of the product signals is the product of either L T lor R T with one of 3 signals F L , F C , F R ; and means for adding weighted sums of the six product signals to obtain output signals L', C', R'.

Claim 9

Dependent Claim 22 words

The decoder of claim 7, wherein said product signals generating means includes six voltage controlled amplifiers for generating the six product signals.

Claim 10

Dependent Claim 51 words

The decoder of claim 3, wherein the matrix means further comprises: means for generating the 3 signals F L , F C , F R from E L , E R l, E C l; and means for performing the matrix multiplications V×G L , V×G R , V×G C .

Claim 11

Dependent Claim 79 words

The decoder of claim 1, further comprising a threshold detection means for detecting the amplitudes of the dominance signals, an averaging means and a switch, wherein the threshold detection means causes an average value of the dominance signals over a preceding time period to be applied to the matrix means upon detecting that the amplitudes of the dominance signals are below a predetermined threshold, so that the directional enhancements are determined by the average value of the dominance signals.

Claim 12

Dependent Claim 48 words

The decoder of claim 1, further comprising an averaging means for applying an average value of the dominance signals over a preceding time period to the matrix means, so that the directional enhancement of the output signals by the matrix means is in accordance with the average value.

Claim 13

Dependent Claim 53 words

The decoder of claim 11, wherein the averaging means has two different time constants, one time constant being operative when at least one dominance signal has an amplitude greater than a threshold value and the other time constant being operative when neither of the dominance signals have an amplitude above said threshold value.

Claim 14

Dependent Claim 53 words

The decoder of claim 12, wherein said averaging means comprises: a variable resistor whose resistance varies inversely with the amplitudes of the dominance signals, said resistor connected between the first or second dominance signal generating means and the matrix means; and an impedance means forming a low pass filter configuration with the resistor.

Claim 15

Dependent Claim 129 words

The decoder of claim 12, wherein said impedance means comprises: a first and a second capacitor means connected in series between ground and a first point in the connection between the variable resistor and the matrix means; a first resistor means forming a charge path for the first capacitor means, the first capacitor means having a capacitance much smaller than that of the second capacitor means so that the voltage across the first capacitor means responds more quickly than that across the second capacitor means to changes in the amplitudes of the dominance signals, so that when dominance signals increase in amplitudes, the averaging means will respond mainly to the voltage across the first capacitor means, thereby enabling the decoder to use the dominance signals to steer the decoder.

Claim 16

Dependent Claim 99 words

The decoder of claim 14, said decoder further comprising means for discharging the second capacitor means so that when the amplitudes of both dominance signals decrease to substantially zero, the first capacitor means is discharged through the first resistor means in a much shorter time than the second capacitor means, so that the directional enhancement of the output signals by the matrix means is substantially determined by the voltage across the second capacitor means before the second capacitor means has been discharged, and so that no directional enhancement is applied when the second capacitor means has been substantially discharged.

Claim 17

Dependent Claim 13 words

The decoder of claim 13, wherein said variable resistor is a transconductance amplifier.

Claim 18

Independent Claim 178 words

A method for decoding two or more channel signals using a directional information system wherein at least four input signals containing directional information have been encoded into the two or more channel signals, said method comprising: generating at least a first dominance signal indicative of the ratio of the amplitudes of a pair of the channel signals; generating at least a second dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and generating a plurality of output signals for which directional effects of the output signals are enhanced in response to said two or more channel signals and to said at least two dominance signals, wherein the first dominance signal D LR and the second dominance signals D CS are given by ##EQU16## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a, k are constants. wherein said output signals generating step includes deriving three directional control signals E L , E R , E C .

Claim 19

Independent Claim 178 words

A method for decoding two or more channel signals using a directional information system wherein at least four input signals containing directional information have been encoded into the two or more channel signals, said method comprising: generating at least a first dominance signal indicative of the ratio of the amplitudes of a pair of the channel signals; generating at least a second dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and generating a plurality of output signals for which directional effects of the output signals are enhanced in response to said two or more channel signals and to said at least two dominance signals, wherein the first dominance signal D LR and the second dominance signals D CS are given by ##EQU16## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a, k are constants. wherein said output signals generating step includes deriving three directional control signals E L , E R , E C .

Claim 20

Dependent Claim 29 words

The method of claim 17, wherein said output signals generating step derives the control signals E L , E R , E C according to the following equations: ##EQU17##

Claim 21

Dependent Claim 73 words

The method of claim 18, wherein the output signals generating step generates the three output signals L', R', C', so that the three output signals are defined by means of the equations below: ##EQU18## where V is a 1 by 4 matrix; G L , G R , are 4 by 2 matrices of predetermined coefficients; b is a constant and F L , F R , F C are given by: ##EQU19##

Claim 22

Dependent Claim 20 words

The method of claim 19, wherein the G L , G R , G C matrices are as follows: ##EQU20##

Claim 23

Dependent Claim 41 words

The method of claim 19, further comprising the step of deriving the G L , G R , G C matrices from four equations Q×G L =H L , Q×G R =H R , Q×G C =H C , where ##EQU21##

Claim 24

Dependent Claim 63 words

The method of claim 19, wherein the output signals generating step further comprises: generating 6 product signals wherein each of the product signals is the product of either L T or R T with one of 3 signals F L , F C , F R ; and adding weighted sums of the six product signals to obtain output signals L', C', R'.

Claim 25

Dependent Claim 49 words

The method of claim 19, wherein the output signals generating step further comprises: generating the 3 signals F L , F C , F R from E L , E R , E C ; and performing the matrix multiplications V×G L , V×G R ; V×G C .

Claim 26

Dependent Claim 170 words

A decoder for decoding two or more channel signals in a directional information system wherein at least four input signals containing directional information are encoded into the two or more channel signals, said decoder comprising: first means for generating at least a first dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and matrix means responsible to said two or more channel signals and to said at least two dominance signals for generating a plurality of output signals for which directional effects of the output signals are enhanced, wherein the first dominance signal D LR and the second dominance signal D CS are given by: ##EQU22## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a is a constant, and wherein said matrix means includes means for deriving four directional control signals E L , E R , E C , E S according to the following equations: ##EQU23##

Claim 27

Dependent Claim 170 words

A decoder for decoding two or more channel signals in a directional information system wherein at least four input signals containing directional information are encoded into the two or more channel signals, said decoder comprising: first means for generating at least a first dominance signal indicative of the ratio of the amplitudes of the sum of and the difference between said pair of the channel signals; and matrix means responsible to said two or more channel signals and to said at least two dominance signals for generating a plurality of output signals for which directional effects of the output signals are enhanced, wherein the first dominance signal D LR and the second dominance signal D CS are given by: ##EQU22## where L T , R T are two channel signals P=L.sub.T +R.sub.T, M=L.sub.T -R.sub.T ; and a is a constant, and wherein said matrix means includes means for deriving four directional control signals E L , E R , E C , E S according to the following equations: ##EQU23##

Claim 28

Dependent Claim 79 words

The decoder of claim 24, further comprising a threshold detection means for detecting the amplitudes of the dominance signals, an averaging means and a switch, wherein the threshold detection means causes an average value of the dominance signals over a preceding time period to be applied to the matrix means upon detecting that the amplitudes of the dominance signals are below a predetermined threshold, so that the directional enhancements are determined by the average value of the doninance signals.

Claim 29

Dependent Claim 82 words

The decoder of claim 24, wherein the directional control signals deriving means derives the four output signals L', R', C', S', so that the four signals are defined by means of the equations below: ##EQU24## where V is a 1 by 5 matrix; G L , G R , G C , G S are 5 by 2 matrices of predetermined coefficients; b is a constant and F L , F R , F C , F S are given by: ##EQU25##

Claim 30

Dependent Claim 13 words

The decoder of claim 26, wherein the value of b is about 0.839.

Claim 31

Dependent Claim 23 words

The decoder of claim 26, wherein the G L , G R , G C , G S matrices are as follows: ##EQU26##

Claim 32

Dependent Claim 46 words

The decoder of claim 26, wherein the G L , G R , G C , G S matrices are derived from four equations Q×G L =H L , Q×G R =H R , Q×G C =H C , Q×G S =H S , where ##EQU27##

Claim 33

Dependent Claim 68 words

The decoder of claim 26, wherein the matrix means further comprises: means for generating 8 product signals wherein each of the signals is the product of either L T or R T with one of 4 signals F L , F C , F R , F S ; and means for adding weighted sums of the eight product signals to obtain output signals L', C', R', S'.

Claim 34

Dependent Claim 22 words

The decoder of claim 30, wherein said product signals generating means includes eight voltage controlled amplifiers for generating the eight product signals.

Claim 35

Dependent Claim 60 words

The decoder of claim 26, wherein the matrix means further comprises: means for generating the 4 signals F L , F C , F R , F S from E L , E R , E C , E S ; and means for performing the matrix multiplications V×G L , V×G R , V×G C , V×G S .

Claim 36

Dependent Claim 48 words

The decoder of claim 24, further comprising an averaging means for applying an average value of the dominance signals over a preceding time period to the matrix means, so that the directional enhancement of the output signals by the matrix means is in accordance with the average value.

Claim 37

Dependent Claim 53 words

The decoder of claim 33, wherein the averaging means has two different time constants, one time constant being operative when at least one dominance signal has an amplitude greater than a threshold value and the other time constant being operative when neither of the dominance signals have an amplitude above said threshold value.

Claim 38

Dependent Claim 53 words

The decoder of claim 34, wherein said averaging means comprises: a variable resistor whose resistance varies inversely with the amplitudes of the dominance signals, said resistor connected between the first or second dominance signal generating means and the matrix means; and an impedance means forming a low pass filter configuration with the resistor.

Claim 39

Dependent Claim 129 words

The decoder of claim 34, wherein said impedance means comprises: a first and a second capacitor means connected in series between ground and a first point in the connection between the variable resistor and the matrix means; a first resistor means forming a charge path for the first capacitor means, the first capacitor means having a capacitance much smaller than that of the second capacitor means so that the voltage across the first capacitor means responds more quickly than that across the second capacitor means to changes in the amplitudes of the dominance signals, so that when dominance signals increase in amplitudes, the averaging means will respond mainly to the voltage across the first capacitor means, thereby enabling the decoder to use the dominance signals to steer the decoder.

Claim 40

Dependent Claim 99 words

The decoder of claim 36, said decoder further comprising means for discharging the second capacitor means so that when the amplitudes of both dominance signals decrease to substantially zero, the first capacitor means is discharged through the first resistor means in a much shorter time than the second capacitor means, so that the directional enhancement of the output signals by the matrix means is substantially determined by the voltage across the second capacitor means before the second capacitor means has been discharged, and so that no directional enhancement is applied when the second capacitor means has been substantially discharged.

Claim 41

Dependent Claim 13 words

The decoder of claim 35, wherein said variable resistor is a transconductance amplifier.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-07-09	1994-01-08	1994-07-10	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-07-09	1998-01-08	1998-07-10	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-07-09	2002-01-08	2002-07-10	$7700.00	Window Closed / Lapsed

Variable matrix decoder

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