Stero enhancement and directivity servo
First Claim
1. A stereo image enhancement system comprising:
- means for providing sum and difference signals representing respectively the sum of and difference between left and right stereo input signals,means for processing the sum and difference signals to provide processed sum and difference signals,servo means responsive to change in amplitude of one of said input signals and to said processed difference signal for varying amplitude of said processed difference signal to provide a directivity enhanced difference signal having an amplitude that varies with variation of said one input signal, andmeans responsive to said processed sum signal and said enhanced difference signal for providing left and right stereo output signals.
2 Assignments
0 Petitions
Accused Products
Abstract
In a stereo system having sum and difference signals that are processed for stereo image enhancement, apparent directivity of the stereo sound is increased by the use of servo systems (40,44) for the left and right processed difference signals (L-R)p, (R-L)p. Each of the left and right servos (40,44) responds to the respective left or right stereo input signal (Lin, Rin) and amplifies increases in the respective left or right processed difference signals. The amount of amplification is controlled by feeding back the amplified or directivity enhanced difference signal (L-R)pe, (R-L)pe, first comparing it with the processed difference signal (L-R)p, (R-L)p before directivity enhancement, and then combining it with the input signal (Lin, Rin) in a preselected ratio so as to control the amount of amplification of the processed difference signal that is provided for directivity enhancement.
132 Citations
72 Claims
-
1. A stereo image enhancement system comprising:
-
means for providing sum and difference signals representing respectively the sum of and difference between left and right stereo input signals, means for processing the sum and difference signals to provide processed sum and difference signals, servo means responsive to change in amplitude of one of said input signals and to said processed difference signal for varying amplitude of said processed difference signal to provide a directivity enhanced difference signal having an amplitude that varies with variation of said one input signal, and means responsive to said processed sum signal and said enhanced difference signal for providing left and right stereo output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A stereo image enhancement system comprising:
-
means for providing sum and difference signals representing respectively the sum and difference between left and right stereo input signals, difference signal equalizing means responsive to said difference signal for providing a first processed difference signal having frequency components in quieter difference frequency bands that are relatively boosted with respect to components in other frequency bands, sum signal equalizing means responsive to said sum signal for modifying amplitude of components of said sum signal in said quieter frequency bands to provide a processed sum signal, means responsive to said first processed difference signal for providing an inverted processed difference signal, left direction enhancement means responsive to amplitude increases of said left stereo input signal and to said first processed difference signal for increasing amplitude of said first processed difference signal to provide an enhanced left processed difference signal having amplitude increase that are greater than corresponding amplitude increases of said left stereo input signal, right direction enhancement means responsive to amplitude increases of said right input stereo signal and to said inverted processed difference signal for increasing amplitude of said inverted processed difference signal to provide an enhanced right processed difference signal having amplitude increases that are greater than corresponding amplitude increases of said right input stereo signal, and means for combining said enhanced right and left processed difference signals and said processed sum signal to provide left and right stereo output signals. - View Dependent Claims (15, 16, 17)
-
-
18. For use in a stereo enhancement system wherein sum and difference signals that represent sum of and difference between left and right stereo input signals are processed to provide a processed sum signal and left and right processed difference signals, and wherein the processed signals are combined to provide left and right stereo output signals, said output signals being fed to a speaker system to produce stereo sound, a method of increasing apparent directivity of sound produced by said speaker system, said method comprising the steps of:
-
enhancing said left processed difference signal by varying its amplitude in accordance with variation of amplitude of said left input signal, thereby providing a directivity enhanced left signal, and enhancing said right processed difference signal by varying its amplitude in accordance with variation of amplitude of said right input signal, thereby providing a directivity enhanced right signal. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. A stereo image enhancement system comprising:
-
means for providing sum and difference signals that respectively represent sum of and difference between left and right stereo input signals, means for processing the sum and difference signals to provide a processed sum signal and left and right processed difference signals, means for combining the sum and difference signals to provide left and right stereo output signals, and servo means for increasing directivity of sound produced in response to said left and right stereo output signals, said servo means comprising; left servo means for increasing amplitude of said left processed difference signal in accordance with amplitude increase of said left stereo input signal to provide a directivity enhanced left signal having an amplitude increase that is greater than said amplitude increase of said left stereo input signal, and right servo means for increasing amplitude of said right processed difference signal in accordance with amplitude increase of said right input stereo signal to provide a directivity enhanced right signal having an amplitude increase that is greater than said amplitude increase of said right stereo input signal. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
-
-
41. A stereo image enhancement system comprising:
-
means for providing sum and difference signals representing respectively the sum of and difference between left and right stereo input signals, means for processing the sum and difference signals to provide processed sum and difference signals, means for combining portions of said processed sum and difference signals to provide a combined signal, servo means responsive to change in amplitude of one of said input signals and to said processed difference signal for varying amplitude of said combined signal to provide a directivity enhanced combined signal having an amplitude that varies with variation of said one input signal, said directivity enhanced combined signal including directivity enhanced sum and difference signal components, means for controlling relative amplitudes of said directivity enhanced sum and difference components, and means responsive to said directivity enhanced sum and difference components for providing left and right stereo output signals.
-
-
42. A stereo image enhancement system comprising:
-
means for providing sum and difference signals representing respectively the sum of and difference between left and right stereo input signals, first means for boosting amplitudes of components of said difference signal in a band of higher frequencies higher than a mid-range band of frequencies relative to amplitudes of components of said sum signal in a corresponding band of higher frequencies, second means for boosting amplitudes of components of said difference signal in a band of lower frequencies lower than said mid-range band of frequencies relative to amplitudes of components of said sum signal in a corresponding band of low frequencies, and means responsive to said boosted components of said difference signal and to said sum signal for providing right and left stereo output signals. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
-
-
55. A stereo image enhancement system comprising:
-
means for providing sum and difference signals representing respectively the sum of and difference between left and right stereo input signals, low pass servoed equalizer means responsive to the sum and difference signals for providing a low processed difference signal component in a band of relatively low frequencies and having an amplitude boosted relative to amplitude of a component of the sum signal in a corresponding band of relatively low frequencies, high pass servoed equalizer means responsive to said sum and difference signals for providing a high processed difference signal component in a band of relatively high frequencies and having an amplitude boosted relative to the amplitude of a component of the sum signal in a corresponding band of relatively high frequencies, means for combining said difference signal with said low processed difference signal component and said high processed difference signal component to provide a composite processed difference signal, means for generating a dynamically enhanced sum signal, and means for combining said composite band processed difference signal, said dynamically enhanced sum signal, and said input signals for providing left and right enhanced stereo output signals. - View Dependent Claims (56, 57, 58)
-
-
59. For use in a stereo enhancement system wherein sum and difference signals that represent sum of and difference between left and right stereo input signals are processed to provide a processed sum signal and left and right processed difference signals, and wherein the processed signals are combined to provide left and right stereo output signals, said output signals being fed to a speaker system to produce stereo sound, a method of enhancing the stereo output signals comprising the steps of:
-
boosting amplitude of components of said difference signal in a band of higher frequencies higher than a center band of frequencies relative to amplitude of components of said sum signal in a corresponding band of higher frequencies, boosting amplitude of components of said difference signal in a band of lower frequencies lower than said center band of frequencies relative to amplitude of components of said sum signal in a corresponding band of lower frequencies, and employing said sum signal and said boosted components of said difference signal for providing right and left stereo enhanced output signals. - View Dependent Claims (60, 61, 62, 63, 64)
-
-
65. An enhanced image stereo sound recording for use in a sound recording playback system, said sound recording comprising:
a record medium embodying signal producing means adapted to operate with a sound recording responsive device to produce left and right stereo output signals that are modifications of left and right stereo source signals, said stereo output signals each comprising a combination of signal components including; (1) a processed high frequency difference signal component which comprises a modification of a band of high frequencies higher than a center band of frequencies of an input difference signal representing the difference of said left and right stereo source signals, (2) a processed low frequency input difference signal component which comprises a modification of a band of low frequencies lower than said center band of frequencies of an input difference signal representing the difference of said left and right stereo source signals, (3) a dynamically enhanced sum signal component which comprises a modification of an input sum signal representing the sum of said left and right stereo source signals, said processed high and low difference signal components being boosted relative to input sum signal components in corresponding frequency bands. - View Dependent Claims (66, 67, 68)
-
69. A method for making a stereo sound recording from left and right stereo source signals comprising the steps of:
-
providing sum and difference signals representing sum of and difference between left and right stereo source signals, separately boosting components of said difference signal in a band of low frequencies lower than a center band of frequencies with respect to components of said sum signal in a corresponding band of low frequencies, separately boosting components of said difference signal in a band of high frequencies higher than said center band of frequencies with respect to components of said sum signal in a corresponding band of high frequencies, combining said boosted high frequency and boosted low frequency difference signal components with the difference signal, said difference signal having frequencies between said low and high frequency band, to thereby provide a processed difference signal, combining the sum signal with said processed difference signal to provide stereo enhanced left and right output signals, feeding the stereo enhanced left and right output signals to a sound recording device, and operating said sound recording device to make a sound recording. - View Dependent Claims (70)
-
-
71. A method for producing an enhanced stereo sound image comprising the steps of:
-
providing sum and difference signals representing sum of and difference between left and right stereo source signals, separately boosting components of said difference signal in a band of low frequencies with respect to components of said sum signal in a corresponding band of low frequencies, separately boosting components of said difference signal in a band of high frequencies higher than said center band of frequencies with respect to components of said sum signal in a corresponding band of high frequencies, combining said boosted high frequency and boosted low frequency difference signal components with components of said difference signal in at least a band of frequencies between said band of low frequencies and said band of high frequencies, to thereby provide a processed wide band difference signal having upper and lower frequency components thereof boosted, and combining said sum signal with said processed wide band difference signal to provide stereo enhanced left and right output signals. - View Dependent Claims (72)
-
Specification