EP0097982A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
FM stereo apparatus
Assignee: Individual
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Filing: 1983-06-02
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Granted: —
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Expires: 2003-06-02
Abstract
Abstract An output matrix adapted to receive an L+R signal component (made up of the sum of L and R stereo components) and an L-R signal component, and to combine these in a manner to produce a separate L output and a separate R output, with certain modifications to the outputs. The higher frequency portion of the L-R signal is passed through a detector which, in turn, causes a leading edge amplifier to transmit to the matrix only those signal portions where there is a relatively abrupt change of amplitude, these being the signal portions which contain the main stereo information which gives the directional information. Also, the L+R signal component, in addition to being transmitted directly to the matrix, is directed through time delay means to produce a time delayed L+R signal component that is also transmitted to the matrix, so as to provide what are called "ambient" sounds to the output of the matrix.
Inventors
- 👤 Robert Weir Carver
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 11:27
CPC Classifications
H; H04; H04S; H04S3/00; H04S3/02; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1646; H04B1/1661
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
239 words
An apparatus to provide an improved FM stereo output, where there is an L+R signal component corresponding to the sum of an L signal and an R signal, and an L-R signal component corresponding to the difference of the L signal and the R signal, said apparatus comprising: a) input means to provide an input signal made up of said L+R signal component and said L-R signal component; b) output means including matrix means to receive and combine said signal components at respective sufficiently high levels to produce a first output mode where there is a first output component corresponding more to said L signal and a second output component corresponding more to said R signal so as to be able to provide directional information, and to receive at least said L+R signal at a sufficiently greater level than said L-R signal to produce a second output mode where said first and second output components both correspond more closely to said L+R signal component; c) control means including detector means to detect from said signal first signal portions where there is a more abrupt change of amplitude and to transmit the L-R signal components of said first signal portions at said sufficiently high level to produce said first output mode, and during second signal portions other than said first signal portions to diminish said L-R signal component relative to said L+R signal component to produce said second output mode.
Claim 2
Independent Claim
239 words
An apparatus to provide an improved FM stereo output, where there is an L+R signal component corresponding to the sum of an L signal and an R signal, and an L-R signal component corresponding to the difference of the L signal and the R signal, said apparatus comprising: a) input means to provide an input signal made up of said L+R signal component and said L-R signal component; b) output means including matrix means to receive and combine said signal components at respective sufficiently high levels to produce a first output mode where there is a first output component corresponding more to said L signal and a second output component corresponding more to said R signal so as to be able to provide directional information, and to receive at least said L+R signal at a sufficiently greater level than said L-R signal to produce a second output mode where said first and second output components both correspond more closely to said L+R signal component; c) control means including detector means to detect from said signal first signal portions where there is a more abrupt change of amplitude and to transmit the L-R signal components of said first signal portions at said sufficiently high level to produce said first output mode, and during second signal portions other than said first signal portions to diminish said L-R signal component relative to said L+R signal component to produce said second output mode.
Claim 3
Dependent Claim
30 words
The apparatus as recited in Claim 1, wherein said control means is arranged to diminish primarily a higher frequency portion of said L-R signal component during said second signal portions.
Claim 4
Dependent Claim
35 words
The apparatus as recited in Claim 2, wherein said control means comprises a low pass filter to transmit a low frequency portion of said L-R component to said matrix means, independently of said detector means.
Claim 5
Dependent Claim
69 words
The apparatus as recited in Claim 3, said control means further comprising amplifier means to receive said L-R signal component and to transmit said L-R signal component to said matrix means, said detector means being responsive to said abrupt change of amplitude to cause said amplifier means to transmit the L-R signal component at a higher level in response to said detector means detecting said abrupt change of amplitude.
Claim 6
Dependent Claim
68 words
The apparatus as recited in Claim 4, further comprising noise control means connected to said matrix means in parallel with said amplifier means to transmit said L-R signal component to said matrix means, said noise control means having selectively operable switch means to diminish the L-R signal component delivered by said noise control means so as to be able to diminish noise contributed by said L-R signal component.
Claim 7
Dependent Claim
37 words
The apparatus as recited in Claim 4, wherein said detector means is responsive primarily to increases in amplitude of said signal to transmit the L-R signal component of said first signal portions at said sufficiently high level.
Claim 8
Dependent Claim
41 words
The apparatus as recited in Claim 4, wherein said detector means is responsive to both abrupt increases and decreases in the amplitude of the signal to transmit the L-R signal component of the first signal portions at said sufficiently high level.
Claim 9
Dependent Claim
45 words
The apparatus as recited in Claim 1, further comprising time delay means adapted to receive said L+R signal component and to provide a delayed L+R signal input to said output means, so as in turn to produce a delayed L+R output from said output means.
Claim 10
Dependent Claim
48 words
The apparatus as recited in Claim 8, wherein said time delay means comprises a first time delay device to produce a first delayed L+R signal input of a shorter delay and a second time delay device to produce a second delayed L+R signal input of a greater delay.
Claim 11
Dependent Claim
43 words
The apparatus as recited in Claim 9, said control means further comprising time delay control means to control amplitude of said delayed L+R signal input in accordance with relative signal strength of the L-R signal component in comparison to the L+R signal component.
Claim 12
Dependent Claim
40 words
The apparatus as recited in Claim 8, further comprising time delay control means to control amplitude of said delayed L+R signal input in accordance with relative signal strength of the L-R signal component in comparison to the L+R signal component.
Claim 13
Dependent Claim
55 words
The apparatus as recited in Claim 13, further comprising filter means to receive the delayed input from the time delay means and to diminish a middle frequency portion of said time delayed input relative to low and high frequency portions thereof, so as to provide a modified input which is transmitted to said output means.
Claim 14
Dependent Claim
147 words
The apparatus as recited in Claim 13, wherein there is control logic means to cause said output means to be selectively responsive to said control means, said control logic means comprising: a) signal strength indicator means responsive to a value related to said input signal in a manner to determine a low signal strength condition where signal strength is below a predetermined signal value, b) multipath distortion indicating means responsive to variations in a value relating to said input signal to indicate a multipath distortion condition where multipath distortion is above a predetermined multipath distortion level, c) logic output means responsive to said signal strength indicator means and said multipath distortion indicator means to cause said output means to be responsive to said control means when the signal strength is below said predetermined signal strength level or said multipath distortion is above said predetermined multipath distortion level.
Claim 15
Dependent Claim
64 words
The apparatus as recited in Claim 16, wherein said control logic means further comprises a time logic circuit means to initiate a predetermined examination time period and to cause said signal strength indicating means and said multipath distortion indicating means to become operative during said examination time period so as to be able to make said logic output operative during said examination time period.
Claim 16
Dependent Claim
31 words
The apparatus as recited in Claim 17, wherein said time logic circuit means includes muting means to cause sound output of said apparatus to become muted during said examination time period.
Claim 17
Dependent Claim
59 words
The apparatus as recited in Claim 18, wherein said time logic circuit means is responsive to station change indicating means of said apparatus, in a manner to initiate said examination time period to cause said signal strength indicator means and said multipath distortion indicator means to become activated where there is a change of station input to said apparatus.
Claim 18
Dependent Claim
110 words
The apparatus as recited in Claim 1, wherein said detector means comprises: a) capacitor means to receive a value related to said L-R signal component and to transmit a differentiated signal related to rate of change of said L-R signal component, b) signal control means responsive to said differentiated signal to produce a control signal related to said differentiated output, c) L-R variable transmitting means adapted to transmit said L-R signal component to said output means at a variable output level, and responsive to said control signal to transmit said L-R signal component at a greater or lesser level depending upon magnitude of said differentiated output from said capacitor means.
References Cited (Backward Citations)
No citation records indexed.
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