Patent US4736433A successfully refreshed from Google Patents.
US4736433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangements for modifying dynamic range using action substitution and superposition techniques
Assignee: Dolby Laboratories Licensing Corp
•
Filing: 1986-04-08
•
Granted: 1988-04-05
•
Expires: 2006-04-08
Abstract
Abstract Circuits for modifying the dynamic range of signals, particularly compressors and expanders for use in noise reduction compander systems, in which the plurality of characteristics are superposed such that as dominant signal components appear, hidden characteristics are revealed and become active. The emergence of characteristics can also be described as "action substitution" in the sense that the action resulting from one, or perhaps more than one characteristic is substituted for one or more other characteristic actions that have the potential to operate in the same frequency and level regions when the level and spectral content of the input signal components change. One particularly useful combination of superposed characteristics is a fixed band characteristic (variable attenuation throughout all or part of the frequency band) and a sliding band characteristic (variable attenuation through part of the frequency band achieved by a variable pass filter). The advantages of such characteristics are obtained, without the disadvantages normally inherent in each characteristic. Fixed band and sliding band circuit elements are operated in various equivalent circuit topologies: in the preferred and simplest arrangement the circuit elements are in a "stack", the output of one element acting as a reference for the other. The elements operate in generally the same level range and at least a partial overlapping in frequency range.
Inventors
- 👤 Ray M. Dolby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:57
CPC Classifications
H; H03; H03G; H03G7/00; H03G9/00; H03G9/005; H03G9/02; H03G9/025
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
98 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising a plurality of circuit elements, each having its own passive or dynamic characteristic action, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that for some level and spectral content of the input signal components the characteristic action of one circuit element substitutes for the characteristic action of another circuit element in at least a portion of the frequency band.
Claim 2
Dependent Claim
98 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising a plurality of circuit elements, each having its own passive or dynamic characteristic action, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that for some level and spectral content of the input signal components the characteristic action of one circuit element substitutes for the characteristic action of another circuit element in at least a portion of the frequency band.
Claim 3
Dependent Claim
116 words
A circuit according to claim 1 wherein the means for interconnecting the circuit elements provides for characteristic action substitution by superposition of characteristics wherein an overall circuit characteristic action is derived from the individual characteristic actions of said plurality of circuit elements such that for any combination of level and spectral content of the input signal components an individual characteristic action defines the overall frequency band or individual characteristic actions each define portions of the overall frequency band, said individual characteristic action or characteristic actions which define all or a portion of the overall frequency band suppressing the effect of any other individual characteristic action or characteristic actions having less effect within the same frequency range.
Claim 4
Dependent Claim
40 words
A circuit according to claim 2 wherein the overall characteristic action for any combination of level and spectral content of input signal components has substantially no greater an effect at any frequency than any individual characteristic operable at that frequency.
Claim 5
Dependent Claim
28 words
A circuit according to claims 1, 2, or 3 wherein the or each element having a dynamic characteristic operates in accordance with a predetermined compression or expansion law.
Claim 6
Dependent Claim
40 words
A circuit according to claims 2 or 3 wherein there are at least two elements having a dynamic characteristic, the dynamic characteristic responding to the level and/or spectral content of signal components in the respective circuit element above a threshold.
Claim 7
Dependent Claim
47 words
A circuit according to claim 5 wherein there are two elements each having dynamic characteristic action, the dynamic characteristic action of one of said elements being a fixed band characteristic action and the dynamic characteristic of the other of said elements being a sliding band characteristic action.
Claim 8
Dependent Claim
41 words
A circuit according to claim 6 wherein the sliding band element includes a gyrator simulated component which inherently generates undesired noise, the circuit further comprising means for removing the gyrator simulated component from the circuit during signal conditions below said threshold.
Claim 9
Dependent Claim
62 words
A circuit according to claim 6 wherein the element having a fixed band characteristic action includes a control circuit and the circuit further comprises means for maintaining the fixed band element control circuit at a level just below its threshold when the level and spectral content of the input signal components are such that the fixed band element is below its threshold.
Claim 10
Dependent Claim
54 words
A circuit according to claim 8 wherein the sliding band characteristic also has a quiescent condition, the circuit further comprising means for moving the sliding band characteristic away from its quiescent condition when the level and spectral content of the input signal components are such that the fixed band element is below its threshold.
Claim 11
Dependent Claim
53 words
A circuit according to claim 6 wherein the sliding band characteristic has a quiescent condition, the circuit further comprising means for moving the sliding band characteristic away from its quiescent condition when the level and spectral content of the input signal components are such that the fixed band element is below its threshold.
Claim 12
Dependent Claim
34 words
A circuit according to claim 5 further comprising means for coupling signal components between or among said elements having dynamic characteristic action to affect the threshold level of one or more of said elements.
Claim 13
Dependent Claim
26 words
A circuit according to claim 11 wherein said means for coupling signal components includes filter means for restricting the frequency band of the coupled signal components.
Claim 14
Dependent Claim
55 words
A circuit according to claim 11 wherein said elements having dynamic characteristic action include means for deriving a control signal, said means for coupling signal components including means for differentially deriving the control signal within an element so that the control signal is substantially unaffected by the signal output(s) of another element or other elements.
Claim 15
Dependent Claim
67 words
A circuit according to claim 2 wherein said means for interconnecting the circuit elements interconnects said circuit elements such that the output of the circuit is effectively the sum of the individual outputs of said circuit elements and the effective input to each circuit element is a differential signal component derived from said input signal and one or more of the individual outputs or a reference potential.
Claim 16
Dependent Claim
107 words
A circuit according to claim 14 wherein said elements are each represented as a three-terminal network wherein each first terminal is a primary input terminal, each second terminal is a secondary input terminal and each third terminal is an output terminal, the input signal being coupled to each of said first terminals, the elements being ordered in a stack wherein the second terminal of a first element is coupled to a reference potential, and the third terminal of each succesive element is coupled to the second terminal of a successive element, and the output is derived from the third terminal of the last element in the stack.
Claim 17
Dependent Claim
64 words
A circuit according to claim 15 wherein the stack of elements includes at least one branch such that the third terminal of an element is coupled to the second terminal of two or more elements which in turn have the output derived from their third terminal or have their third terminal coupled to the second terminal of one or more elements in the stack.
Claim 18
Dependent Claim
136 words
A circuit according to claim 2 wherein the circuit is a dual-path circuit in which said plurality of circuit elements and means for interconnecting the circuit elements include a further path, the circuit further comprising a main path which is linear with respect to dynamic range, a combining circuit in the main path, said further path having its input coupled to the input or output of the main path and its output coupled to the combining circuit, the further path providing a signal which, at least in a part of the frequency band, boosts or bucks the main path signal by way of the combining circuit, but which is so limited that, in the upper part of the input dynamic range, the further path signal is limited to a value smaller than the main path signal.
Claim 19
Dependent Claim
85 words
A circuit according to claim 17 wherein the further path itself includes a plurality of series circuits, all but the last in the series of said series circuits being a dual-path circuit, and further combining means for summing the outputs of the further path(s) of the dual-path series circuit(s) and the output of the last series circuit to provide the further path signal of the overall dual path circuit, whereby the main path or paths in said series circuit or circuits constitute secondary main paths.
Claim 20
Dependent Claim
36 words
A circuit according to claim 18 further comprising means including a single pole switch for selectively applying the further path signal of the overall dual path circuit to boost or buck the overall main path signal.
Claim 21
Dependent Claim
85 words
A circuit according to claim 18 further comprising yet a further path for the overall dual path circuit, including therein means for generating an equalization signal, said yet a further path having its input coupled to the input or the output of the main path and its output coupled to the combining circuit, the yet a further path providing an equalization signal which, at least in a part of the frequency band, boosts or bucks the main path signal by way of the combining circuit.
Claim 22
Dependent Claim
83 words
A circuit according to claim 17 wherein the further path itself includes a plurality of series circuits, at least one of said series circuits being a dual-path circuit, the circuit further comprising means in parallel with the plurality of series circuits for inverting the input signal to said further path, and means including a single pole switch for selectively applying the further path signal summed with the inverted input signal to the further path to boost or buck the overall main path signal.
Claim 23
Dependent Claim
79 words
A circuit according to claim 17 further comprising yet a further path including therein means for generating an equalization signal, said yet a further path having its input coupled to the input or the output of the main path and its output coupled to the combining circuit, the yet a further path providing an equalization signal which, at least in a part of the frequency band, boosts or bucks the main path signal by way of the combining circuit.
Claim 24
Dependent Claim
43 words
A combination of circuits according to claims 2 or 3 wherein each circuit operates only in a portion of the overall frequency band, the combination of the circuits providing modification of the dynamic range of input signal components throughout the overall frequency band.
Claim 25
Dependent Claim
32 words
The combination of circuits according to claim 23 wherein there are two circuits operating, respectively, in the upper part of the frequency band and in the lower part of the frequency band.
Claim 26
Dependent Claim
51 words
The combination of circuits according to claim 24 wherein the circuits are for use at audio frequencies and the circuit operating in the upper part of the frequency band operates mainly above 800 Hz and the circuit operating in the lower part of the frequency band operates mainly below 800 Hz.
Claim 27
Dependent Claim
50 words
A circuit according to claim 1 wherein the circuit is for compressing the dynamic range of input signal components within a frequency band, said means for interconnecting providing characteristic action substitution or augmentation such that for very low level signal components the transmission through the circuit tends to be maximized.
Claim 28
Dependent Claim
50 words
A circuit according to claim 1 wherein the circuit is for expanding the dynamic range of input signal components within a frequency band, said means for interconnecting providing characteristic action substitution or augmentation such that for very low level signal components the transmission through the circuit tends to be minimized.
Claim 29
Independent Claim
71 words
A method for conformally equalizing input signal components within a frequency band, comprising providing a plurality of characteristics actions, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and substituting one characteristic action with another characteristic action in at least a portion of the frequency band for some level and spectral content of the input signal components.
Claim 30
Independent Claim
71 words
A method for conformally equalizing input signal components within a frequency band, comprising providing a plurality of characteristics actions, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and substituting one characteristic action with another characteristic action in at least a portion of the frequency band for some level and spectral content of the input signal components.
Claim 31
Independent Claim
92 words
A method for modifying the dynamic range of input signal components within a frequency band, comprising selecting two circuit characteristic actions represented by the voltage transfer functions t 1 (s) and t 2 (s), respectively, at least one characteristic action being dynamic, the characteristic actions operating at least partially within substantially the same frequency and level region, and operating the circuit characteristics such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by V.sub.out =V.sub.in [t.sub.1 (s)+t.sub.2 (s)-t.sub.1 (s)t.sub.2 (s)].
Claim 32
Independent Claim
92 words
A method for modifying the dynamic range of input signal components within a frequency band, comprising selecting two circuit characteristic actions represented by the voltage transfer functions t 1 (s) and t 2 (s), respectively, at least one characteristic action being dynamic, the characteristic actions operating at least partially within substantially the same frequency and level region, and operating the circuit characteristics such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by V.sub.out =V.sub.in [t.sub.1 (s)+t.sub.2 (s)-t.sub.1 (s)t.sub.2 (s)].
Claim 33
Independent Claim
89 words
A method for modifying the dynamic range of input signal components within a frequency band, comprising selecting three circuit characteristic actions represented by the voltage transfer functions t 1 (s), t 2 (s), and t 3 (s), respectively, at least one characteristic action being dynamic, the characteristic actions operating at least partially within substantially the same frequency and level region, and operating the circuit characteristics such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by ##EQU2##
Claim 34
Independent Claim
89 words
A method for modifying the dynamic range of input signal components within a frequency band, comprising selecting three circuit characteristic actions represented by the voltage transfer functions t 1 (s), t 2 (s), and t 3 (s), respectively, at least one characteristic action being dynamic, the characteristic actions operating at least partially within substantially the same frequency and level region, and operating the circuit characteristics such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by ##EQU2##
Claim 35
Dependent Claim
102 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising two circuit elements, each having its own passive or dynamic characteristic action represented by the voltage transfer functions t 1 (s) and t 2 (s), respectively, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by V.sub.out =V.sub.in [t.sub.1 (s)+t.sub.2 (s)-t.sub.1 (s)t.sub.2 (s)].
Claim 36
Dependent Claim
102 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising two circuit elements, each having its own passive or dynamic characteristic action represented by the voltage transfer functions t 1 (s) and t 2 (s), respectively, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by V.sub.out =V.sub.in [t.sub.1 (s)+t.sub.2 (s)-t.sub.1 (s)t.sub.2 (s)].
Claim 37
Dependent Claim
99 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising three circuit elements, each having its own passive or dynamic characteristic action represented by the voltage transfer functions t 1 (s), t 2 (s), and t 3 (s), respectively, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by ##EQU3##
Claim 38
Dependent Claim
99 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising three circuit elements, each having its own passive or dynamic characteristic action represented by the voltage transfer functions t 1 (s), t 2 (s), and t 3 (s), respectively, at least one having a dynamic characteristic action, the characteristic actions operating at least partially within substantially the same frequency and level region, and means for interconnecting the circuit elements such that when input signal components are applied, represented by the voltage V in , the output voltage V out is represented by ##EQU3##
Claim 39
Dependent Claim
228 words
A circuit selectably switchable as a compressor or an expander for modifying the dynamic range of input signal components within a frequency band, comprising a circuit path including a plurality of series dual-path stages, forming a compressor or expander, each of said dual-path stages including a main path which is linear with respect to dynamic range, a combining circuit in the main path, and a further path which has its input coupled to the input or output of the main path and its output coupled to the combining circuit, the further path providing a signal which at least in a part of the frequency band, boosts the main path signal in the compressor means and bucks the main path signal in the expander means, by wy of combining circuit, but which in each case is so limited that, in the upper part of the input dynamic range, the further path signal is limited to a value smaller than the main path signal. means in parallel with said circuit path for input signal to said circuit path, and an overall dual-path circuit, including a further main path which is linear with respect to dynamic range, and means including a single pole switch for selectively applying the output of said circuit path summed with the inverted input to said circuit path to boost or buck the further main path signal.
Claim 40
Dependent Claim
228 words
A circuit selectably switchable as a compressor or an expander for modifying the dynamic range of input signal components within a frequency band, comprising a circuit path including a plurality of series dual-path stages, forming a compressor or expander, each of said dual-path stages including a main path which is linear with respect to dynamic range, a combining circuit in the main path, and a further path which has its input coupled to the input or output of the main path and its output coupled to the combining circuit, the further path providing a signal which at least in a part of the frequency band, boosts the main path signal in the compressor means and bucks the main path signal in the expander means, by wy of combining circuit, but which in each case is so limited that, in the upper part of the input dynamic range, the further path signal is limited to a value smaller than the main path signal. means in parallel with said circuit path for input signal to said circuit path, and an overall dual-path circuit, including a further main path which is linear with respect to dynamic range, and means including a single pole switch for selectively applying the output of said circuit path summed with the inverted input to said circuit path to boost or buck the further main path signal.
Claim 41
Dependent Claim
118 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising a plurality of dynamic action stages connected in series, the stages having staggered thresholds, at least two of said stages including first and second substages, the first and second substages each having a single pole band determining filter, the band determining filter in each of said first substages having substantially the same high pass frequency characteristic and corner frequency, and the band determining filter in each of said second substages having substantially the same low pass frequency characteristic and corner frequency, all of said corner frequencies being substantially the same, whereby the overall effect of the series stages provides a quasi-multi-pole effect.
Claim 42
Dependent Claim
118 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising a plurality of dynamic action stages connected in series, the stages having staggered thresholds, at least two of said stages including first and second substages, the first and second substages each having a single pole band determining filter, the band determining filter in each of said first substages having substantially the same high pass frequency characteristic and corner frequency, and the band determining filter in each of said second substages having substantially the same low pass frequency characteristic and corner frequency, all of said corner frequencies being substantially the same, whereby the overall effect of the series stages provides a quasi-multi-pole effect.
Claim 43
Dependent Claim
130 words
The circuit of claim 34 wherein each of said stages comprises a dual path circuit, said dual-path circuit including a main path which is linear with respect to dynamic range, a combining circuit in the main path, two further paths comprising said first and second substages having their inputs coupled to the input or output of the main path and their outputs coupled to the combining circuit, the further paths providing a signal which, at least in a part of the frequency band, boosts or bucks the main path signal by way of the combining circuit, but which is so limited that, in the upper part of the input dynamic range, the further path signal is limited to a value smaller than the main path signal for most signal conditions.
Claim 44
Dependent Claim
84 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising an active circuit element producing undesired noise, said active circuit element having a characteristic dynamic action operating in accordance with a predetermined compression or expansion law. When the input signal components are above a threshold, the circuit further comprising means for removing the element from the circuit when the input signal components are below said threshold so that the element does not contribute noise to the circuit output.
Claim 45
Dependent Claim
84 words
A circuit for modifying the dynamic range of input signal components within a frequency band, comprising an active circuit element producing undesired noise, said active circuit element having a characteristic dynamic action operating in accordance with a predetermined compression or expansion law. When the input signal components are above a threshold, the circuit further comprising means for removing the element from the circuit when the input signal components are below said threshold so that the element does not contribute noise to the circuit output.
References Cited (Backward Citations)
US30468A
Cited
US3795876A
Cited
USRE30468E
Cited
US4363007A
Cited
US4490691A
Cited
US4412100A
Cited
US4498060A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-05 | 1991-10-05 | 1992-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-05 | 1995-10-05 | 1996-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-05 | 1999-10-05 | 2000-04-05 | $7700.00 | Window Closed / Lapsed |