US3706041A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic tuning circuit
Assignee: Emerson Electric Co
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Filing: 1970-10-20
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Granted: 1972-12-12
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Expires: 1990-10-20
Abstract
Abstract An automatic tuning device for use with a radio receiver includes a capacitor for storing a voltage which determines the frequency to which the device is tuned, means for charging the capacitor, and a control element connected across the capacitor for preventing further charging or discharging of the capacitor after the receiver has been properly tuned. When it is desired to tune the receiver to a new station, an advance switch is actuated, causing the enabling voltage from the control device to be removed so that the capacitor can be further charged. When the capacitor has been charged to a voltage corresponding to the high end of the frequency band, a unijunction transistor across the capacitor is fired, causing the capacitor to discharge to a voltage corresponding approximately to the lowest frequency in the band of interest.
Inventors
- 👤 Friedrich Johann Krausser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:51
CPC Classifications
H; H03; H03J; H03J7/00; H03J7/18; H03J7/20; H03J7/24; H03J7/26
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
207 words
Apparatus for use in automatically tuning an electronic device having an IF stage for receiving an IF signal across a preselected frequency band comprising a capacitor for storing a voltage which determines the frequency to which said device is tuned; current generating means for charging said capacitor; a variable impedance solid state, semi-conductor control element connected across said capacitor for limiting the charge on said capacitor in response to an applied input voltage; an advance switch for operatively connecting said capacitor and said current generating means; means responsive to actuation of said advance switch for producing a muting signal; means responsive to said muting signal or the presence of said IF signal for generating said input voltage; means for maintaining said muting signal for a predetermined time interval after said advance switch is actuated, said time interval being long enough to enable the device to tune off of any frequency in the band but not so long as to cause the device to tune past a desired frequency in said band, and means responsive to a preselected voltage across said capacitor corresponding to the high end of said frequency band for discharging said capacitor to a voltage corresponding approximately to the low end of said frequency band.
Claim 2
Dependent Claim
207 words
Apparatus for use in automatically tuning an electronic device having an IF stage for receiving an IF signal across a preselected frequency band comprising a capacitor for storing a voltage which determines the frequency to which said device is tuned; current generating means for charging said capacitor; a variable impedance solid state, semi-conductor control element connected across said capacitor for limiting the charge on said capacitor in response to an applied input voltage; an advance switch for operatively connecting said capacitor and said current generating means; means responsive to actuation of said advance switch for producing a muting signal; means responsive to said muting signal or the presence of said IF signal for generating said input voltage; means for maintaining said muting signal for a predetermined time interval after said advance switch is actuated, said time interval being long enough to enable the device to tune off of any frequency in the band but not so long as to cause the device to tune past a desired frequency in said band, and means responsive to a preselected voltage across said capacitor corresponding to the high end of said frequency band for discharging said capacitor to a voltage corresponding approximately to the low end of said frequency band.
Claim 3
Dependent Claim
16 words
Apparatus according to claim 1, wherein said means for discharging said capacitor comprises a unijunction transistor.
Claim 4
Dependent Claim
33 words
Apparatus according to claim 1, wherein said electronic device is a radio receiver having an intermediate frequency stage, and wherein said means for preventing includes means for cutting off said intermediate frequency stage.
Claim 5
Dependent Claim
24 words
Apparatus according to claim 3, further including means for varying said predetermined time interval, depending upon the frequency to which said receiver is tuning.
Claim 6
Dependent Claim
70 words
Apparatus according to claim 4, wherein said means for varying said time interval comprises a capacitor which is connected to a voltage source upon actuation of said advance switch, said means for pReventing being disabled when the voltage across said second-named capacitor reaches a predetermined level and wherein there is further provided a continuous advance switch for alternatively enabling said preventing means, said continuous advance switch bypassing said second-named capacitor.
Claim 7
Dependent Claim
46 words
Apparatus according to claim 5, wherein said means for varying said time interval comprises a variable impedance means for varying the time required to charge said second-named capacitor, said variable impedance means including a solid-state control element responsive to the tuning voltage across said first-named capacitor.
References Cited (Backward Citations)
US3560858A
Cited
US3575662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-12 | 1976-06-12 | 1976-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-12 | 1980-06-12 | 1980-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-12 | 1984-06-12 | 1984-12-12 | $7700.00 | Window Closed / Lapsed |