Patent US4413289A successfully refreshed from Google Patents.
US4413289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital recording and playback method and apparatus
Assignee: SRI International Inc
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Filing: 1981-03-13
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Granted: 1983-11-01
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Expires: 2001-03-13
Abstract
Abstract A recording-playback system is disclosed wherein analog signals are converted to digital form which then are compressed and encoded using a variable length code. The encoded signals are temporarily stored in a buffer memory from which they are read out to a variable speed recorder for recording thereof. The rate at which the encoded signals are read out to the recorder and the recording speed are controlled in direct proportion to the percent fullness of the buffer memory for recording with substantially constant bit density on the recording medium. The ratio of the buffer memory read out rate and recording speed may be selected for recording with a substantially maximum bit density. A playback unit for the system includes a variable speed playback for playing back the recorded digital signals. The signals are temporarily stored in a buffer memory, from which memory they are read out to a decoder which operates at a substantially constant word rate. The speed of operation of the variable speed playback means is controlled in inverse proportion to the fullness of the buffer memory to maintain a supply of signals for use by the decoder. The decoded signals are supplied to a digital decompression filter for digital reconstruction thereof. A digital to analog converter converts the digital signals to analog form.
Inventors
- 👤 Charles S. Weaver
- 👤 Joseph H. Chadwick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:35
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/80; A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/333; A61B5/336; G; G11; G11B; G11B20/00; G11B20/00007; G11B20/10; G11B20/14; G11B20/1403; G11B20/1423; G11B20/1426; A61B5/72; A61B5/7232
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
119 words
In a digital recording system for recording a bit stream in which bits occur at a varying bit rate on a recording medium with a high and substantially constant bit density, the combination comprising buffer memory means for temporarily storing said bits to be recorded, variable speed recording means for recording bits from said buffer means on a recording medium, and means responsive to the number of bits contained in said buffer memory means for continuously controlling both the rate at which bits are read from said buffer memory means to said recording means and the speed of said recording means for recording said varying bit rate stream with a substantially constant high bit density on said recording medium.
Claim 2
Dependent Claim
119 words
In a digital recording system for recording a bit stream in which bits occur at a varying bit rate on a recording medium with a high and substantially constant bit density, the combination comprising buffer memory means for temporarily storing said bits to be recorded, variable speed recording means for recording bits from said buffer means on a recording medium, and means responsive to the number of bits contained in said buffer memory means for continuously controlling both the rate at which bits are read from said buffer memory means to said recording means and the speed of said recording means for recording said varying bit rate stream with a substantially constant high bit density on said recording medium.
Claim 3
Dependent Claim
31 words
In a digital recording system as defined in claim 1 wherein the bit stream to be recorded comprises a stream of variable length words occurring at a substantially constant word rate.
Claim 4
Dependent Claim
139 words
In a digital recording system for recording on a recording medium a bit stream in which bits occur at a varying bit rate, the combination comprising buffer memory means for temporarily storing said bits to be recorded, variable speed recording means for recording bits from said buffer memory means on a recording medium, and means for continuously controlling both the rate at which bits are read from said buffer memory means to said recording means and the speed of said recording means for recording said bit stream with a substantially constant bit density on said recording medium, said controlling means including means for counting the difference in the number of bits of the bit stream written into said buffer memory means and the number of bits read out of said buffer memory means to said variable speed recording means.
Claim 5
Dependent Claim
139 words
In a digital recording system for recording on a recording medium a bit stream in which bits occur at a varying bit rate, the combination comprising buffer memory means for temporarily storing said bits to be recorded, variable speed recording means for recording bits from said buffer memory means on a recording medium, and means for continuously controlling both the rate at which bits are read from said buffer memory means to said recording means and the speed of said recording means for recording said bit stream with a substantially constant bit density on said recording medium, said controlling means including means for counting the difference in the number of bits of the bit stream written into said buffer memory means and the number of bits read out of said buffer memory means to said variable speed recording means.
Claim 6
Dependent Claim
41 words
In a digital recording system as defined in claim 3 wherein the rate at which bits are read from said buffer memory means and the speed of said recording means are in direct proportion to the output from said counting means.
Claim 7
Dependent Claim
119 words
In a digital recording system for recording a bit stream having a varying bit rate on a recording medium with a substantially constant bit density, the combination comprising buffer memory means into which said varying bit rate stream to be recorded is written for temporary storage of said bits, variable speed recording means for recording bits from said buffer memory means on a recording medium, and means for controlling both the rate at which bits are read from said buffer memory means to said variable recording means and the speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number read out therefrom.
Claim 8
Dependent Claim
119 words
In a digital recording system for recording a bit stream having a varying bit rate on a recording medium with a substantially constant bit density, the combination comprising buffer memory means into which said varying bit rate stream to be recorded is written for temporary storage of said bits, variable speed recording means for recording bits from said buffer memory means on a recording medium, and means for controlling both the rate at which bits are read from said buffer memory means to said variable recording means and the speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number read out therefrom.
Claim 9
Dependent Claim
244 words
In a digital recording system for recording a bit stream having a varying bit rate on a recording medium with a substantially constant bit density, the combination comprising buffer memory means into which said varying bit rate stream to be recorded is written for temporary storage of said bits, variable speed recording means for recording bits from said buffer memory means on a recording medium, said variable speed recording means including a recording head and a variable speed motor for relatively moving said recording head and recording medium, and means for controlling both the rate at which bits are read from said buffer memory means to said variable recording means and the speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number read out therefrom, said controlling means including means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for obtaining a control signal proportional to said difference. a variable frequency clock, means for connecting said control signal to said variable frequency clock for controlling the clock frequency, means for connecting the output from said variable frequency clock to said buffer memory means for establishing the rate at which bits are read from said buffer memory means, and means for connecting said control signal to said variable speed motor for control of the motor speed.
Claim 10
Dependent Claim
244 words
In a digital recording system for recording a bit stream having a varying bit rate on a recording medium with a substantially constant bit density, the combination comprising buffer memory means into which said varying bit rate stream to be recorded is written for temporary storage of said bits, variable speed recording means for recording bits from said buffer memory means on a recording medium, said variable speed recording means including a recording head and a variable speed motor for relatively moving said recording head and recording medium, and means for controlling both the rate at which bits are read from said buffer memory means to said variable recording means and the speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number read out therefrom, said controlling means including means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for obtaining a control signal proportional to said difference. a variable frequency clock, means for connecting said control signal to said variable frequency clock for controlling the clock frequency, means for connecting the output from said variable frequency clock to said buffer memory means for establishing the rate at which bits are read from said buffer memory means, and means for connecting said control signal to said variable speed motor for control of the motor speed.
Claim 11
Dependent Claim
27 words
In a digital recording system as defined in claim 6 wherein the recording medium comprises recording tape movable by said variable speed motor past said recording head.
Claim 12
Dependent Claim
31 words
In a digital recording system as defined in claim 5 wherein the bit stream to be recorded comprises a stream of variable length words produced at a substantially constant word rate.
Claim 13
Dependent Claim
146 words
In a recording system for compactly recording digital data on a recording medium, the combination comprising a source of fixed word length digital signals, digital compression filter means for digital compression of said digital signals from said source, digital encoding means for encoding the output from said digital compression filter means, the output from said encoding means comprising variable word length signals, buffer memory means for temporary storage of the variable word length signals from said encoding means, variable speed recording means for recording the variable word length signals read out from said buffer memory means, and means for controlling both the rate at which bits are read out from said buffer memory means to said recording means and the recording speed of said recording means in direct proportion to the number of bits written in said buffer memory means and not yet read out therefrom.
Claim 14
Dependent Claim
146 words
In a recording system for compactly recording digital data on a recording medium, the combination comprising a source of fixed word length digital signals, digital compression filter means for digital compression of said digital signals from said source, digital encoding means for encoding the output from said digital compression filter means, the output from said encoding means comprising variable word length signals, buffer memory means for temporary storage of the variable word length signals from said encoding means, variable speed recording means for recording the variable word length signals read out from said buffer memory means, and means for controlling both the rate at which bits are read out from said buffer memory means to said recording means and the recording speed of said recording means in direct proportion to the number of bits written in said buffer memory means and not yet read out therefrom.
Claim 15
Dependent Claim
38 words
In a recording system as defined in claim 9 wherein the ratio of the read out rate from said buffer memory means and the recording speed provides for recording on the recording medium with substantially maximum bit density.
Claim 16
Dependent Claim
36 words
In a recording system as defined in claim 9 wherein said source of fixed word length digital signals comprises analog to digital converter means for converting an analog input signal into fixed word length digital signals.
Claim 17
Dependent Claim
113 words
In a method of recording a bit stream in which the bits occur at a varying bit rate, the steps including transferring the varying bit rate stream to be recorded to continuously variable speed recording means through buffer memory means for recording of the bit stream on a recording medium included in said variable speed recording means, and continuously controlling the read out rate of bits from said buffer memory means and the speed of operation of said variable speed recording means as a function of the number of bits contained in said buffer memory means for recording of the varying bit rate stream with substantially constant bit density on the recording medium.
Claim 18
Dependent Claim
113 words
In a method of recording a bit stream in which the bits occur at a varying bit rate, the steps including transferring the varying bit rate stream to be recorded to continuously variable speed recording means through buffer memory means for recording of the bit stream on a recording medium included in said variable speed recording means, and continuously controlling the read out rate of bits from said buffer memory means and the speed of operation of said variable speed recording means as a function of the number of bits contained in said buffer memory means for recording of the varying bit rate stream with substantially constant bit density on the recording medium.
Claim 19
Dependent Claim
60 words
In a method of recording as defined in claim 12 wherein the step of controlling the read out rate of bits from said buffer memory means and the speed of operation of said variable speed recording means is in response to the difference in the number of bits written into said buffer memory means and the number read out therefrom.
Claim 20
Dependent Claim
132 words
In a method of digital recording a varying bit rate stream of bits such as a stream of variable length words produced at a substantially constant word rate, or the like, on a recording medium with substantially constant bit density, the steps including feeding said stream to buffer memory means for temporary storage of the stream bits, reading bits from said buffer memory means to variable speed recording means for recording the same, controlling the rate at which bits are read out from said buffer memory means and the recording speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number of bits read out therefrom to record said bits with a substantially constant bit density.
Claim 21
Dependent Claim
132 words
In a method of digital recording a varying bit rate stream of bits such as a stream of variable length words produced at a substantially constant word rate, or the like, on a recording medium with substantially constant bit density, the steps including feeding said stream to buffer memory means for temporary storage of the stream bits, reading bits from said buffer memory means to variable speed recording means for recording the same, controlling the rate at which bits are read out from said buffer memory means and the recording speed of said variable speed recording means in direct proportion to the difference in the number of bits written into said buffer memory means and the number of bits read out therefrom to record said bits with a substantially constant bit density.
Claim 22
Dependent Claim
176 words
In a playback system for playback from a recording medium upon which variable word length digital signals are recorded with a substantially uniform bit density, the combination including circuit means for processing variable word length digital signals at a substantially constant word rate, variable speed playback means, including a pickup head and a variable speed motor for relatively moving said pickup head and recording medium, for playing back recorded variable word length digital signals from said recording medium, buffer memory means into which variable word length digital signals from said variable speed playback means are written for temporary storage thereof and from which said stored signals are read out to said circuit means, and means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for controlling the motor speed of said variable speed playback means in inverse proportion to the output from said difference responsive means for constantly maintaining a supply of digital signals in said buffer means for use by said circuit means.
Claim 23
Dependent Claim
176 words
In a playback system for playback from a recording medium upon which variable word length digital signals are recorded with a substantially uniform bit density, the combination including circuit means for processing variable word length digital signals at a substantially constant word rate, variable speed playback means, including a pickup head and a variable speed motor for relatively moving said pickup head and recording medium, for playing back recorded variable word length digital signals from said recording medium, buffer memory means into which variable word length digital signals from said variable speed playback means are written for temporary storage thereof and from which said stored signals are read out to said circuit means, and means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for controlling the motor speed of said variable speed playback means in inverse proportion to the output from said difference responsive means for constantly maintaining a supply of digital signals in said buffer means for use by said circuit means.
Claim 24
Dependent Claim
145 words
In a playback system for reproducing original fixed word length digital signals which have been compressed and encoded using variable length code words and recorded with a substantially uniform bit density on a recording medium, the combination comprising, variable speed playback means for playing back the recorded encoded signals from said recording medium, buffer memory means into which encoded signals from said playback means are written for temporary storage thereof, decoder means operable at a substantially constant word rate, means for reading out encoded signals from said buffer memory means to said decoder means for decoding said signals, digital decompression filter means responsive to the decoded output signals from said decoder means for digital reconstruction of the original fixed word length digital signals, and means for controlling the speed of operation of said variable speed playback means to maintain the buffer memory means partially full.
Claim 25
Dependent Claim
145 words
In a playback system for reproducing original fixed word length digital signals which have been compressed and encoded using variable length code words and recorded with a substantially uniform bit density on a recording medium, the combination comprising, variable speed playback means for playing back the recorded encoded signals from said recording medium, buffer memory means into which encoded signals from said playback means are written for temporary storage thereof, decoder means operable at a substantially constant word rate, means for reading out encoded signals from said buffer memory means to said decoder means for decoding said signals, digital decompression filter means responsive to the decoded output signals from said decoder means for digital reconstruction of the original fixed word length digital signals, and means for controlling the speed of operation of said variable speed playback means to maintain the buffer memory means partially full.
Claim 26
Dependent Claim
42 words
In a playback system as defined in claim 16 wherein said controlling means includes means for producing a control signal in response to the difference in the number of bits written into said buffer memory means and the number read out therefrom.
Claim 27
Dependent Claim
151 words
In a playback system for playback of digital signals from a recording medium upon which digital signals comprising variable length words are recorded with a substantially uniform bit density, the combination including, uniform speed playback means for playing back recorded digital signals from said recording means, buffer memory means into which variable word length digital signals from said uniform speed playback means are written at a substantially constant bit rate for temporary storage thereof and from which said stored signals are read out at a varying bit rate, circuit means operable at a varying word rate for processing variable word length digital signals read out from said buffer memory means, and means for simultaneously controlling both the rate at which bits are read out from said buffer memory means and the word rate at which said circuit means operates to prevent overflow or emptying of said buffer memory means during playback.
Claim 28
Dependent Claim
151 words
In a playback system for playback of digital signals from a recording medium upon which digital signals comprising variable length words are recorded with a substantially uniform bit density, the combination including, uniform speed playback means for playing back recorded digital signals from said recording means, buffer memory means into which variable word length digital signals from said uniform speed playback means are written at a substantially constant bit rate for temporary storage thereof and from which said stored signals are read out at a varying bit rate, circuit means operable at a varying word rate for processing variable word length digital signals read out from said buffer memory means, and means for simultaneously controlling both the rate at which bits are read out from said buffer memory means and the word rate at which said circuit means operates to prevent overflow or emptying of said buffer memory means during playback.
Claim 29
Dependent Claim
39 words
In a playback system as defined in claim 18 wherein the read out rate from said buffer memory means and word rate of operation of said circuit means deviates no more than substantially 1% from a fixed word rate.
Claim 30
Dependent Claim
200 words
In a playback system for playback of digital signals from a recording medium upon which digital signals are recorded with a substantially uniform bit density, the combination including, uniform speed playback means for playing back recorded digital signals from said recording means, buffer memory means into which digital signals from said uniform speed playback means are written at a substantially constant bit rate for temporary storage thereof and from which said stored signals are read out at a varying bit rate, circuit means operable at a varying word rate for processing digital signals read out from said buffer memory means, and means for controlling the rate at which bits are read out from said buffer memory means and the word rate at which said circuit means operates to prevent overflow or emptying of said buffer memory means during playback, said controlling means including means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for controlling the rate at which bits are read out from said buffer memory means and the rate of operation of said circuit means in direct proportion to the output from said difference responsive means.
Claim 31
Dependent Claim
200 words
In a playback system for playback of digital signals from a recording medium upon which digital signals are recorded with a substantially uniform bit density, the combination including, uniform speed playback means for playing back recorded digital signals from said recording means, buffer memory means into which digital signals from said uniform speed playback means are written at a substantially constant bit rate for temporary storage thereof and from which said stored signals are read out at a varying bit rate, circuit means operable at a varying word rate for processing digital signals read out from said buffer memory means, and means for controlling the rate at which bits are read out from said buffer memory means and the word rate at which said circuit means operates to prevent overflow or emptying of said buffer memory means during playback, said controlling means including means responsive to the difference in the number of bits written into said buffer memory means and the number read out therefrom for controlling the rate at which bits are read out from said buffer memory means and the rate of operation of said circuit means in direct proportion to the output from said difference responsive means.
Claim 32
Dependent Claim
171 words
In a playback system for reproducing original fixed word length digital signals which have been compressed and encoded using variable length code words and recorded with a substantially uniform bit density on a recording medium, the combination comprising, uniform speed playback means for playing back the recorded encoded signals from said recording medium, buffer memory means into which encoded signals from said playback means are written for temporary storage thereof, decoder means operable at a variable word rate, means for reading out encoded signals from said buffer memory means to said decoder means for decoding said signals, digital decompression filter means operable at a variable word rate and responsive to the decoded output signals from said decoder means for digital reconstruction of the original fixed word length digital signals, and means for controlling the read-out rate from said buffer memory means and rate of operation of said decoder means and digital decompression filter means to prevent overflow of said buffer memory means and emptying thereof during playback from the recording medium.
Claim 33
Dependent Claim
171 words
In a playback system for reproducing original fixed word length digital signals which have been compressed and encoded using variable length code words and recorded with a substantially uniform bit density on a recording medium, the combination comprising, uniform speed playback means for playing back the recorded encoded signals from said recording medium, buffer memory means into which encoded signals from said playback means are written for temporary storage thereof, decoder means operable at a variable word rate, means for reading out encoded signals from said buffer memory means to said decoder means for decoding said signals, digital decompression filter means operable at a variable word rate and responsive to the decoded output signals from said decoder means for digital reconstruction of the original fixed word length digital signals, and means for controlling the read-out rate from said buffer memory means and rate of operation of said decoder means and digital decompression filter means to prevent overflow of said buffer memory means and emptying thereof during playback from the recording medium.
Claim 34
Dependent Claim
41 words
In a playback system as defined claim 21 wherein said controlling means includes means for producing a control signal in response to the difference in the number of bits written into said buffer memory means and the number read out therefrom.
Claim 35
Dependent Claim
34 words
In a playback system as defined in claim 21 wherein the word rate of operation of said decoder means and digital decompression filter means is within substantially ±1 percent of a fixed word rate.
Claim 36
Independent Claim
141 words
A system for recording analog signals, such as music, or the like, in compact digital form on a recording medium, comprising in combination means for converting said analog signals to be recorded to fixed word length digital signals, digital compression filter means for digital compression of said digital signals from said converting means, digital encoding means for encoding the output from said digital compression filter means, the output from said encoding means comprising variable word length signals, buffer memory means for temporary storage of the variable word length signals from said encoding means, uniform speed recording means for recording the variable word length signals read out from said buffer memory means, and means for reading bits out of said buffer memory means at a substantially uniform bit rate of recording thereof with a substantially constant bit density on the recording medium.
Claim 37
Independent Claim
141 words
A system for recording analog signals, such as music, or the like, in compact digital form on a recording medium, comprising in combination means for converting said analog signals to be recorded to fixed word length digital signals, digital compression filter means for digital compression of said digital signals from said converting means, digital encoding means for encoding the output from said digital compression filter means, the output from said encoding means comprising variable word length signals, buffer memory means for temporary storage of the variable word length signals from said encoding means, uniform speed recording means for recording the variable word length signals read out from said buffer memory means, and means for reading bits out of said buffer memory means at a substantially uniform bit rate of recording thereof with a substantially constant bit density on the recording medium.
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USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1986-10-31 | 1987-05-02 | 1987-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-31 | 1991-05-02 | 1991-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-31 | 1995-05-02 | 1995-11-01 | $7700.00 | Window Closed / Lapsed |