US4142729A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gramophone equipment
Assignee: Pico Electronics Ltd
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Filing: 1977-11-29
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Granted: 1979-03-06
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Expires: 1997-11-29
Abstract
Abstract A record player has a record track selection system using sensing means to scan a record to identify selected record tracks, the sensing means feeding signal processing circuitry having a gain or threshold adapted to individual record characteristics as determined by a record scan prior to track identification.
Inventors
- 👤 Harold M. McLennan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:08
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/08; G11B27/00; G11B27/10; G11B27/19; G11B27/24; G11B27/26; G11B3/00; G11B3/02; G11B3/08; G11B3/095
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
205 words
A record player comprising: a turntable; a tone arm having a pick-up; record track selection means for selecting a track of a record to be played by the player; sensing means for scanning across a record on said turntable to produce a signal representing the record reflectivity thereby to identify bands of relatively low groove density separating recoded tracks of a record; control means for causing the sensing means to effect a first and a second scan of a record on said turntable, the first to assess record reflectivity and the second to identify the band immediately preceding the track selected by said record track selection means; means for causing the pick-up to engage with the band identified during the second scan; and processing circuitry for processing the signal of the sensing means and having means for analysing the signal of the sensing means during the first scan to obtain a measure of the peaks of said signal and means for adjusting at least one of the gain value and threshold value of the circuitry during the second scan in dependence upon said measure and in the sense tending to compensate for the variations which occur between records in the amplitude levels of said signal.
Claim 2
Dependent Claim
205 words
A record player comprising: a turntable; a tone arm having a pick-up; record track selection means for selecting a track of a record to be played by the player; sensing means for scanning across a record on said turntable to produce a signal representing the record reflectivity thereby to identify bands of relatively low groove density separating recoded tracks of a record; control means for causing the sensing means to effect a first and a second scan of a record on said turntable, the first to assess record reflectivity and the second to identify the band immediately preceding the track selected by said record track selection means; means for causing the pick-up to engage with the band identified during the second scan; and processing circuitry for processing the signal of the sensing means and having means for analysing the signal of the sensing means during the first scan to obtain a measure of the peaks of said signal and means for adjusting at least one of the gain value and threshold value of the circuitry during the second scan in dependence upon said measure and in the sense tending to compensate for the variations which occur between records in the amplitude levels of said signal.
Claim 3
Dependent Claim
41 words
A record player according to claim 1, wherein the analysing means is operable to obtain said measure from the level of the greatest peak it is able to detect in the signal obtained from the sensing means during the first scan.
Claim 4
Dependent Claim
25 words
A record player according to claim 2, wherein the analysing means utilizes the adjusting means for obtaining a measure of the peaks of the signal.
Claim 5
Dependent Claim
19 words
A record player according to claim 3, wherein the adjusting means comprises means for adjusting said value in steps.
Claim 6
Dependent Claim
45 words
A record player according to claim 4, wherein the adjusting means comprise a ladder network of switches and influencing elements for influencing one of the gain and threshold values of the circuitry, the switches being operable in a sequence to sequentially step said one value.
Claim 7
Dependent Claim
56 words
A record player according to claim 5, wherein the analysing means comprises a multi-stage register arranged to step in synchronism with said switches to store a bit in a stage corresponding to the switch associated with the required circuitry value, that register bit then governing the adjusting means of the processing circuitry during the second scan.
Claim 8
Dependent Claim
21 words
A record player according to claim 6, wherein the register is a random access memory providing switching signals for said switches.
References Cited (Backward Citations)
US3937903A
Cited
US3934136A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-05 | 1982-09-04 | 1983-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-05 | 1986-09-04 | 1987-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-05 | 1990-09-04 | 1991-03-06 | $7700.00 | Window Closed / Lapsed |