Patent EP0300732A2 successfully refreshed from Google Patents.
EP0300732A2
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Apparatus for reproducing a digital signal
Assignee: Sony Corp
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Filing: 1988-07-19
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Granted: —
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Expires: 2008-07-19
Abstract
Abstract In an apparatus for reproducing a recorded digital signal and suitable for use in a data recorder (1), error detecting signals are generated (14) for respective reproduced header portions of a main data area and a sub-data area formed in each track, the error detecting signals are counted (30) for a predetermined period, and the counted value is compared with a predetermined value. A data error condition is determined in accordance with the comparison result, so that it is possible to simplify the circuit arrangement and detect an error condition in the recorded digital data.
Inventors
- 👤 Azusa Patents Division Katsumata
- 👤 Shigeyuki Patents Division Satomura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 12:40
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/18; G11B20/1816; G11B20/1806; G11B20/1809
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
172 words
An apparatus for reproducing a digital signal from a recording medium (12) which has tracks patterned thereon in each of which are recorded a plurality of blocks of data signals, each block of data including a header, a parity of the header and other digital information, the apparatus comprising: means (1, A′, B′) for reproducing the recorded signals from the recording medium (12); and error detecting means (14), which monitors the reproduced header parity, for detecting good parity for each block and supplying a corresponding good parity detection signal; characterized by: counting means (42 to 45) for counting the good parity detection signal from the error detecting means (14); and comparing means (52) for comparing the error count in the counting means (42 to 45) with a predetermined value and supplying a write error decision signal, indicating that the corresponding data block has no uncorrectable errors, when the count exceeds the predetermined value, and indicating that the corresponding data block has uncorrectable errors, when the count does not exceed the predetermined value.
Claim 2
Independent Claim
172 words
An apparatus for reproducing a digital signal from a recording medium (12) which has tracks patterned thereon in each of which are recorded a plurality of blocks of data signals, each block of data including a header, a parity of the header and other digital information, the apparatus comprising: means (1, A′, B′) for reproducing the recorded signals from the recording medium (12); and error detecting means (14), which monitors the reproduced header parity, for detecting good parity for each block and supplying a corresponding good parity detection signal; characterized by: counting means (42 to 45) for counting the good parity detection signal from the error detecting means (14); and comparing means (52) for comparing the error count in the counting means (42 to 45) with a predetermined value and supplying a write error decision signal, indicating that the corresponding data block has no uncorrectable errors, when the count exceeds the predetermined value, and indicating that the corresponding data block has uncorrectable errors, when the count does not exceed the predetermined value.
Claim 3
Dependent Claim
34 words
Apparatus according to claim 1 wherein the error detecting means (14) includes means (14) for checking the parity of the header in each block and for generating a pulse when the parity is correct.
Claim 4
Dependent Claim
66 words
Apparatus according to claim 2 wherein the counting means (42 to 45) counts the pulses, and the comparing means (52) compares the counted value of the pulses with the predetermined value and supplies the write error decision signal, indicating that the data in one of the tracks contains no errors or only correctable errors, when the counted value of the pulses is above the predetermined value.
Claim 5
Dependent Claim
75 words
Apparatus according to claim 1, claim 2 or claim 3 further comprising: envelope detecting means (31) for detecting an amplitude envelope from the reproduced signal, comparing the same with a reference value, and supplying a gate signal when the amplitude of the envelope exceeds the reference value; and gate means (36 to 39) for gating the output from the error detecting means (14) in response to the gate signal from the envelope detecting means (31).
Claim 6
Dependent Claim
56 words
Apparatus according to claim 4 wherein the reproduce signal has an amplitude envelope having a main region and a sub-region, corresponding to different portions of the recorded signal, and wherein the envelope detecting means (31) has different reference values for digital data in the main region and digital data in the sub-region of the reproduced signal.
Claim 7
Dependent Claim
30 words
Apparatus according to any one of the preceding claims wherein the signal reproducing means (1, A′, B′) and the error detecting means (14) include a digital audio tape recorder (1).
Claim 8
Dependent Claim
85 words
Apparatus according to any one of the preceding claims wherein the recording medium (12) is a magnetic tape (12), and the means (1, A′, B′) for reproducing the signal includes a pair of rotary heads (A′, B′) for reproducing a signal from the tape (12), and further including means (A, B) for re-recording digital data on the tape (12) by another pair of rotary heads (A, B) in response to the write error decision signal indicating an uncorrectable error condition of the recorded digital data.
Claim 9
Independent Claim
142 words
A method of reproducing a digital signal from a recording medium (12) which has tracks patterned thereon in each of which are recorded a plurality of blocks of data signals, each block of data including a header, a parity of the header and other digital information, the method comprising the steps of: reproducing the recorded signals from the recording medium (12); and monitoring the reproduced header parity and detecting good parity for each block and supplying a corresponding good parity detection signal; characterized by: counting the good parity detection signals; and comparing the error count with a predetermined value and supplying a write error decision signal, indicating that the corresponding data block has no uncorrectable errors, when the count exceeds the predetermined value, and indicating that the corresponding data block has uncorrectable errors, when the count does not exceed the predetermined value.
Claim 10
Independent Claim
142 words
A method of reproducing a digital signal from a recording medium (12) which has tracks patterned thereon in each of which are recorded a plurality of blocks of data signals, each block of data including a header, a parity of the header and other digital information, the method comprising the steps of: reproducing the recorded signals from the recording medium (12); and monitoring the reproduced header parity and detecting good parity for each block and supplying a corresponding good parity detection signal; characterized by: counting the good parity detection signals; and comparing the error count with a predetermined value and supplying a write error decision signal, indicating that the corresponding data block has no uncorrectable errors, when the count exceeds the predetermined value, and indicating that the corresponding data block has uncorrectable errors, when the count does not exceed the predetermined value.
Claim 11
Dependent Claim
35 words
A method according to claim 8 wherein the monitoring and error detecting step includes the step of checking the parity of the header in each block and generating a pulse when the parity is correct.
Claim 12
Dependent Claim
63 words
A method according to claim 9 wherein the counting step counts the pulses, and the comparing step compares the counted value of the pulses with the predetermined value and supplies the write error decision signal, indicating that the data in one of the tracks contains no errors or only correctable errors, when the counted value of the pulses is above the predetermined value.
Claim 13
Dependent Claim
62 words
A method according to claim 8, claim 9 or claim 10 further comprising: detecting an amplitude envelope from the reproduced signal, comparing it with a reference value, and supplying a gate signal when the amplitude of the envelope exceeds the reference value; and gating the output from the error detecting step in response to the gate signal from the envelope detecting step.
Claim 14
Dependent Claim
56 words
A method according to claim 11 wherein the reproduced signal has an amplitude envelope having a main region and a sub-region, corresponding to different portions of the recorded signal, and wherein the envelope detecting step uses different reference values for digital data in the main region and digital data in the sub-region of the reproduced signal.
Claim 15
Independent Claim
33 words
A method according to any one of claims 8 to 12 wherein the signal reproducing step and the error detecting step are carried out by means of a digital audio tape recorder (1).
Claim 16
Independent Claim
85 words
A method according to any one of claims 8 to 13 wherein the recording medium (12) is a magnetic tape (12), and the step of reproducing the signal includes reproducing a signal from the tape (12) by means of a pair of rotary heads (A′, B′), and further including the step of re-recording digital data on the tape (12) by another pair of rotary heads (A, B) in response to the write error decision signal indicating an uncorrectable error condition of the recorded digital data.
References Cited (Backward Citations)
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