US5796842A
Expired / Lapsed
US
⏱️ 0.0 years remaining
BTSC encoder
Assignee: MIDDLESEX SAVINGS BANK
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Filing: 1996-06-07
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Granted: 1998-08-18
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Expires: 2016-06-07
Abstract
Abstract The disclosed BTSC encoder includes a left high pass filter means for receiving a digital left channel audio signal and for digitally high pass filtering the digital left channel audio signal and thereby generating a digital left filtered signal; a right high pass filter means for receiving a digital right channel audio signal and for digitally high pass filtering the digital right channel audio signal and thereby generating a digital right filtered signal; a matrix means for receiving the digital left and digital right filtered signals, and including means for summing the digital left and digital right filtered signals and thereby generating a digital sum signal, and including means for subtracting one of the digital left and digital right filtered signals from the other of the digital left and digital right filtered signals and thereby generating a digital difference signal; a difference channel processing means for digitally processing the digital difference signal; and a sum channel processing means for digitally processing the digital sum signal.
Inventors
- 👤 Christopher M. Hanna
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:00
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88; G; G10; G10L; G10L19/00; G10L19/008; H04N; H04N5/00; H04N5/44; H04N5/60; H04N5/602; H04N7/00; H04N7/06; H04R; H04R5/00; H04R5/04; H04S; H04S5/00; H04S5/02
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
272 words
A digital BTSC signal encoder for encoding digital left and right channel audio signals at a predetermined sample rate so that the encoded left and right channel audio signals can be subsequently decoded so as to reproduce the digital left and right channel audio signals with little or no distortion of the signal content of the digital left and right channel audio signals, said encoder comprising: (A) left high pass filter means for receiving the digital left channel audio signal and for digitally high pass filtering said digital left channel audio signal and thereby generating a digital left filtered signal; (B) right high pass filter means for receiving the digital right channel audio signal and for digitally high pass filtering said digital right channel audio signal and thereby generating a digital right filtered signal; (C) matrix means for receiving said digital left and digital right filtered signals, and including means for summing said digital left and digital right filtered signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and digital right filtered signals from the other of said digital left and digital right filtered signals and thereby generating a digital difference signal; (D) difference channel processing means for digitally processing said digital difference signal; (E) sum channel processing means for digitally processing said digital sum signal; wherein the left and right high pass filter means, the matrix means, and the difference channel processing means and the sum channel processing means each operate at a predetermined sample rate so as to preserve the signal content of said digital left and right channel audio signals.
Claim 2
Dependent Claim
272 words
A digital BTSC signal encoder for encoding digital left and right channel audio signals at a predetermined sample rate so that the encoded left and right channel audio signals can be subsequently decoded so as to reproduce the digital left and right channel audio signals with little or no distortion of the signal content of the digital left and right channel audio signals, said encoder comprising: (A) left high pass filter means for receiving the digital left channel audio signal and for digitally high pass filtering said digital left channel audio signal and thereby generating a digital left filtered signal; (B) right high pass filter means for receiving the digital right channel audio signal and for digitally high pass filtering said digital right channel audio signal and thereby generating a digital right filtered signal; (C) matrix means for receiving said digital left and digital right filtered signals, and including means for summing said digital left and digital right filtered signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and digital right filtered signals from the other of said digital left and digital right filtered signals and thereby generating a digital difference signal; (D) difference channel processing means for digitally processing said digital difference signal; (E) sum channel processing means for digitally processing said digital sum signal; wherein the left and right high pass filter means, the matrix means, and the difference channel processing means and the sum channel processing means each operate at a predetermined sample rate so as to preserve the signal content of said digital left and right channel audio signals.
Claim 3
Dependent Claim
31 words
An encoder according to claim 1, wherein said left and right high pass filter means are each characterized by a cutoff frequency that is less than or equal to 50 Hz.
Claim 4
Dependent Claim
29 words
An encoder according to claim 2, wherein said left and right high pass filter means are each characterized by a passband and a substantially flat response in said passband.
Claim 5
Dependent Claim
26 words
A digital BTSC signal encoder according to claim 3, further including digital high pass filter means for high pass filtering said digital left and right signals.
Claim 6
Dependent Claim
29 words
A digital BTSC signal encoder according to claim 1, wherein said sum channel processing means and said difference channel processing means are both implemented on a single integrated circuit.
Claim 7
Dependent Claim
44 words
A digital BTSC signal encoder according to claim 1, wherein said digital left and right channel audio signals are digitally sampled signals sampled with a sampling frequency substantially equal to N times 15,734 Hz, N being an integer greater than or equal to three.
Claim 8
Dependent Claim
69 words
A digital BTSC signal encoder according to claim 1, wherein said difference channel processing means includes: (A) difference input means for receiving said digital difference signal; (B) difference output means for providing an encoded difference signal; and (C) a difference signal transmission path coupled to said difference input means and to said difference output means, and including means for generating said encoded difference signal from said digital difference signal.
Claim 9
Dependent Claim
78 words
A digital BTSC signal encoder according to claim 7, wherein said difference channel processing means further includes spectral compression means for receiving a spectral compression input signal from said difference signal transmission path and for compressing said spectral compression input signal according to a function of an energy level of said encoded difference signal and thereby generating a spectral compression output signal, and including means for applying said spectral compression output signal to said difference signal transmission path.
Claim 10
Dependent Claim
46 words
A digital BTSC signal encoder according to claim 8, wherein said spectral compression means includes means for measuring a first energy level of said encoded difference signal in a first select spectral portion, and for generating a first control signal representative of said first energy level.
Claim 11
Dependent Claim
79 words
A digital BTSC signal encoder according to claim 9, wherein said spectral compression means further includes a variable emphasis filter for receiving and digitally filtering said spectral compression input signal and thereby generating said spectral compression output signal, the filtering provided by said variable emphasis filter being characterized by a transfer function including a plurality of coefficients, said spectral compression means further including means for selecting said plurality of coefficients according to a function of said first control signal.
Claim 12
Dependent Claim
24 words
A digital BTSC signal encoder according to claim 10, wherein said means for selecting said plurality of coefficients includes a memory look up table.
Claim 13
Dependent Claim
54 words
A digital BTSC signal encoder according to claim 11, wherein said means for selecting said plurality of coefficients includes (a) logarithmic generator means for receiving and logarithmically compressing said first control signal and thereby generating a logarithmically compressed signal and (b) means for applying said logarithmically compressed signal to said memory look up table.
Claim 14
Dependent Claim
34 words
A digital BTSC signal encoder according to claim 10, wherein said means for selecting said plurality of coefficients includes means for calculating said plurality of coefficients as a function of said first control signal.
Claim 15
Dependent Claim
57 words
A digital BTSC signal encoder according to claim 10, wherein said spectral compression means includes spectral bandpass filter means for receiving and filtering a signal representative of said encoded difference signal and thereby generating a spectral signal, said filtering provided by said spectral bandpass filter means being characterized by a passband in said first select spectral portion.
Claim 16
Dependent Claim
47 words
A digital BTSC signal encoder according to claim 14, wherein said spectral compression means includes first RMS level detector means for receiving said spectral signal and for generating therefrom said first control signal, said first control signal being representative of an RMS value of said spectral signal.
Claim 17
Dependent Claim
36 words
A digital BTSC signal encoder according to claim 14, wherein said spectral compression means includes amplifying means for receiving and amplifying said encoded difference signal and thereby generating said signal representative of said encoded difference signal.
Claim 18
Dependent Claim
77 words
A digital BTSC signal encoder according to claim 10, wherein said difference channel processing means includes wideband compression means for receiving a wideband compression input signal from said difference signal transmission path and for compressing said wideband compression input signal according to a function of an energy level of said encoded difference signal and thereby generating a wideband compression output signal, and including means for applying said wideband compression output signal to said difference signal transmission path.
Claim 19
Dependent Claim
21 words
A digital BTSC signal encoder according to claim 17, wherein said spectral compression input signal comprises said wideband compression output signal.
Claim 20
Dependent Claim
46 words
A digital BTSC signal encoder according to claim 17, wherein said wideband compression means includes means for measuring a second energy level of said encoded difference signal in a second select spectral portion, and for generating a second control signal representative of said second energy level.
Claim 21
Dependent Claim
43 words
A digital BTSC signal encoder according to claim 19, wherein said wideband compression means includes amplifier means for receiving and amplifying said wideband compression input signal using a gain controlled by said second control signal and thereby generating said wideband compression output signal.
Claim 22
Dependent Claim
58 words
A digital BTSC signal encoder according to claim 20, wherein said wideband compression means further includes wideband bandpass filter means for receiving and filtering a signal representative of said encoded difference signal and thereby generating a wideband signal, said filtering provided by said wideband bandpass filter means being characterized by a passband in said second select spectral portion.
Claim 23
Dependent Claim
48 words
A digital BTSC signal encoder according to claim 21, wherein said wideband compression means further includes second RMS level detector means for receiving said wideband signal and for generating therefrom said second control signal, said second control signal being representative of an RMS value of said wideband signal.
Claim 24
Dependent Claim
79 words
A digital BTSC signal encoder according to claim 17, wherein said difference channel processing means further includes first low pass filter means for receiving a first low pass filter input signal from said difference signal transmission path and including means for low pass filtering said first low pass filter input signal and thereby generating a first low pass filter output signal, and including means for applying said first low pass filter output signal to said difference signal transmission path.
Claim 25
Dependent Claim
79 words
A digital BTSC signal encoder according to claim 23, wherein said difference channel processing means further includes second low pass filter means for receiving a second low pass filter input signal from said difference signal transmission path and including means for low pass filtering said second low pass filter input signal and thereby generating a second low pass filter output signal, and including means for applying said second low pass filter output signal to said difference signal transmission path.
Claim 26
Dependent Claim
68 words
A digital BTSC signal encoder according to claim 24, wherein said sum channel processing means includes: (A) sum input means for receiving said digital sum signal; (B) sum output means for providing a conditioned sum signal; (C) a sum signal transmission path coupled to said sum input means and to said sum output means, and including means for generating said conditioned sum signal from said digital sum signal.
Claim 27
Dependent Claim
85 words
A digital BTSC signal encoder according to claim 25, wherein said sum channel processing means further includes (a) sum channel low pass filter means for receiving a sum channel low pass filter input signal from said sum signal transmission path and (b) means for low pass filtering said sum channel low pass filter input signal and thereby generating a sum channel low pass filter output signal, and including means for applying said sum channel low pass filter output signal to said sum signal transmission path.
Claim 28
Dependent Claim
40 words
A digital BTSC signal encoder according to claim 26, wherein the filtering provided by a cascade of said first and second low pass filter means is substantially similar to the filtering provided by said sum channel low pass filtering means.
Claim 29
Dependent Claim
29 words
A digital BTSC signal encoder according to claim 27, wherein the filtering provided by said sum channel low pass filtering means is characterized by a null at 15,734 Hz.
Claim 30
Dependent Claim
32 words
A digital BTSC signal encoder according to claim 28, wherein the filtering provided by said sum channel low pass filtering means is characterized by a pass band between zero and 15 kHz.
Claim 31
Dependent Claim
29 words
A digital BTSC signal encoder according to claim 29, wherein the filtering provided by said sum channel low pass filtering means is characterized by a cutoff above 15 kHz.
Claim 32
Dependent Claim
70 words
A digital BTSC signal encoder according to claim 26, wherein said difference channel processing means further includes (a) first fixed preemphasis filter means for receiving a first preemphasis input signal from said difference signal transmission path, (b) means for filtering said first preemphasis input signal so as to generate a first preemphasis output signal, and (c) means for applying said first preemphasis output signal to said difference signal transmission path.
Claim 33
Dependent Claim
69 words
A digital BTSC signal encoder according to claim 31, wherein said difference channel processing means further includes (a) second fixed preemphasis filter means for receiving a second preemphasis input signal from said difference signal transmission path, (b) means for filtering said second preemphasis input signal and thereby generating a second preemphasis output signal, and (c) means for applying said second preemphasis output signal to said difference signal transmission path.
Claim 34
Dependent Claim
74 words
A digital BTSC signal encoder according to claim 32, wherein said sum channel processing means further includes (a) 75 μs preemphasis filter means for receiving a 75 μs preemphasis input signal from said sum signal transmission path (b) means for filtering said 75 μs preemphasis input signal so as to generate a 75 μs preemphasis output signal, and (c) means for applying said 75 μs preemphasis output signal to said sum signal transmission path.
Claim 35
Dependent Claim
69 words
A digital BTSC signal encoder according to claim 33, wherein said sum channel processing means further includes (a) static equalization filter means for receiving a static equalization input signal from said sum signal transmission path, (b) means for filtering said static equalization input signal so as to generate a static equalization output signal, and (c) means for applying said static equalization output signal to said sum signal transmission path.
Claim 36
Dependent Claim
80 words
A digital BTSC signal encoder according to claim 34, wherein the filtering provided by said second preemphasis filter means is characterized by a second preemphasis phase response, the filtering provided by said 75 μs preemphasis filter means is characterized by a 75 μs preemphasis phase response, and a difference between said second preemphasis phase response and a first reference phase response is substantially similar to a difference between said 75 μs preemphasis phase response and a second reference phase response.
Claim 37
Dependent Claim
59 words
A digital BTSC signal encoder according to claim 35, wherein the filtering provided by said first preemphasis filter means is characterized by a first preemphasis phase response, the filtering provided by said static equalization filter means is characterized by a static equalization phase response, and said first preemphasis phase response is substantially similar to said static equalization phase response.
Claim 38
Dependent Claim
23 words
A digital BTSC signal encoder according to claim 36, wherein said first preemphasis input signal comprises said first low pass filter output signal.
Claim 39
Dependent Claim
21 words
A digital BTSC signal encoder according to claim 37, wherein said wideband compression input signal comprises said first preemphasis output signal.
Claim 40
Dependent Claim
21 words
A digital BTSC signal encoder according to claim 38, wherein said second preemphasis input signal comprises said spectral compression output signal.
Claim 41
Dependent Claim
74 words
A digital BTSC signal encoder according to claim 36, wherein said difference channel processing means further includes (a) difference dynamic equalization filter means for receiving a difference dynamic equalization input signal from said difference signal transmission path, (b) means for filtering said difference dynamic equalization input signal so as to generate a difference dynamic equalization output signal, and (c) means for applying said difference dynamic equalization output signal to said difference signal transmission path.
Claim 42
Dependent Claim
74 words
A digital BTSC signal encoder according to claim 40, wherein said sum channel processing means further includes (a) sum dynamic equalization filter means for receiving a sum dynamic equalization input signal from said sum signal transmission path, (b) means for filtering said sum dynamic equalization input signal so as to generate a sum dynamic equalization output signal, and (c) means for applying said sum dynamic equalization output signal to said sum signal transmission path.
Claim 43
Dependent Claim
87 words
A digital BTSC signal encoder according to claim 41, wherein the filtering provided by said difference dynamic equalization filter means is characterized by a difference dynamic equalization phase response, the filtering provided by said variable emphasis filter is characterized by a variable emphasis phase response, the filtering provided by said sum dynamic equalization filter means is characterized by a sum dynamic equalization phase response, said difference dynamic equalization, variable emphasis, and sum dynamic equalization phase responses all varying according to a function of said second control signal.
Claim 44
Dependent Claim
33 words
A digital BTSC signal encoder according to claim 25, further including composite modulator means for receiving said encoded difference signal and said conditioned sum signal and for generating therefrom a composite modulated signal.
Claim 45
Dependent Claim
185 words
A digital BTSC signal encoder, comprising: (A) left channel sampling means for receiving an analog left channel audio signal and for sampling said analog left channel audio signal at a sampling frequency substantially equal to N times 15,734 Hz and thereby generating a digital left signal; (B) right channel sampling means for receiving an analog right channel audio signal and for sampling said analog right channel audio signal at a sampling frequency substantially equal to N times 15,734 Hz and thereby generating a digital right signal; (C) matrix means for receiving said digital left and digital right signals, and including means for summing said digital left and digital right signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and digital right signals from the other of said digital left and digital right signals and thereby generating a digital difference signal; (D) difference channel processing means for digitally processing said digital difference signal; and (E) sum channel processing means for digitally processing said digital sum signal; wherein N is an integer greater than or equal to three.
Claim 46
Dependent Claim
185 words
A digital BTSC signal encoder, comprising: (A) left channel sampling means for receiving an analog left channel audio signal and for sampling said analog left channel audio signal at a sampling frequency substantially equal to N times 15,734 Hz and thereby generating a digital left signal; (B) right channel sampling means for receiving an analog right channel audio signal and for sampling said analog right channel audio signal at a sampling frequency substantially equal to N times 15,734 Hz and thereby generating a digital right signal; (C) matrix means for receiving said digital left and digital right signals, and including means for summing said digital left and digital right signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and digital right signals from the other of said digital left and digital right signals and thereby generating a digital difference signal; (D) difference channel processing means for digitally processing said digital difference signal; and (E) sum channel processing means for digitally processing said digital sum signal; wherein N is an integer greater than or equal to three.
Claim 47
Dependent Claim
240 words
A digital BTSC signal encoder for encoding digital left and right channel audio signals at a predetermined sample rate so that the encoded left and right channel audio signals can be subsequently decoded so as to reproduce the digital left and right channel audio signals with little or no distortion of the signal content of the digital left and right channel audio signals, said encoder comprising: (A) matrix means for receiving a digital left channel audio signal and a digital right channel audio signal, and including means for summing said digital left and right channel audio signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and right channel audio signals from the other of said digital left and right channel audio signals and thereby generating a digital difference signal; (B) difference channel processing means for digitally processing said digital difference signal, said digital processing introducing a first phase error to said digital difference signal; (C) sum channel processing means for processing said digital sum signal and including means for introducing a second phase error to said digital sum signal and thereby compensating for said first phase error introduced into said digital difference signal; wherein the matrix means, the difference channel processing means and the sum channel processing means each operate at a predetermined sample rate so as to preserve the signal content of said digital left and right channel audio signals.
Claim 48
Dependent Claim
240 words
A digital BTSC signal encoder for encoding digital left and right channel audio signals at a predetermined sample rate so that the encoded left and right channel audio signals can be subsequently decoded so as to reproduce the digital left and right channel audio signals with little or no distortion of the signal content of the digital left and right channel audio signals, said encoder comprising: (A) matrix means for receiving a digital left channel audio signal and a digital right channel audio signal, and including means for summing said digital left and right channel audio signals and thereby generating a digital sum signal, and including means for subtracting one of said digital left and right channel audio signals from the other of said digital left and right channel audio signals and thereby generating a digital difference signal; (B) difference channel processing means for digitally processing said digital difference signal, said digital processing introducing a first phase error to said digital difference signal; (C) sum channel processing means for processing said digital sum signal and including means for introducing a second phase error to said digital sum signal and thereby compensating for said first phase error introduced into said digital difference signal; wherein the matrix means, the difference channel processing means and the sum channel processing means each operate at a predetermined sample rate so as to preserve the signal content of said digital left and right channel audio signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-17 | 2002-02-16 | 2002-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-17 | 2006-02-16 | 2006-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-17 | 2010-02-16 | 2010-08-18 | $7700.00 | Window Closed / Lapsed |