§
Luxuse
Patent Intelligence
Sign In
← Back to Patent Explorer
US4628540A Expired / Lapsed US ⏱️ 0.0 years remaining

Tuning arrangement having a substantially constant frequency difference between an RF-circuit and an oscillator circuit

Assignee: US Philips Corp
•
Filing: 1985-03-25
•
Granted: 1986-12-09
•
Expires: 2005-03-25
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A tuning arrangement including a mixer stage, a tunable RF-circuit coupled to an input of said mixer stage, an oscillator circuit, coupled to another input of said mixer stage, having a tunable resonant circuit and, for both circuits, a common tuning to mutually different resonant frequencies, of which at least the circuit having the higher resonant frequency includes, a parallel circuit of, on the one hand, a circuit inductance and, on the other hand, a series arrangement of a tuning capacitor and a padding capacitor. For an acceptable tracking between the resonant frequencies of the two circuits, more specifically in the lower frequency portion of the tuning range, the padding capacitor is shunted by a coil which considerably reduces the effect of the capacitance of the padding capacitor at least in the lower frequency portion of the tuning range.

Inventors

  • 👤 Johannes H. Hendriks

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 23:44
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/28

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 144 words
A tuning arrangement comprising a mixer stage, a tunable RF-circuit coupled to an input of the mixer stage, an oscillator circuit, coupled to another input of said mixer stage, having a tunable resonant circuit, and means, coupled to said RF- and oscillator circuits, for tuning said circuits to mutually different resonant frequencies, of which at least one of said circuits, having a highest of said resonant frequencies, comprises a parallel arrangement of a circuit inductance and a series arrangement of a tuning capacitor and a padding capacitor, characterized in that in said one circuit, the padding capacitor is shunted by a coil, which reduces the effect of the capacitance of the padding capacitor within the tuning range of said one circuit, and the resonant frequency determined by the coil and the padding capacitor is located below a lowest tuning frequency of said one circuit.
Claim 2
Dependent Claim 144 words
A tuning arrangement comprising a mixer stage, a tunable RF-circuit coupled to an input of the mixer stage, an oscillator circuit, coupled to another input of said mixer stage, having a tunable resonant circuit, and means, coupled to said RF- and oscillator circuits, for tuning said circuits to mutually different resonant frequencies, of which at least one of said circuits, having a highest of said resonant frequencies, comprises a parallel arrangement of a circuit inductance and a series arrangement of a tuning capacitor and a padding capacitor, characterized in that in said one circuit, the padding capacitor is shunted by a coil, which reduces the effect of the capacitance of the padding capacitor within the tuning range of said one circuit, and the resonant frequency determined by the coil and the padding capacitor is located below a lowest tuning frequency of said one circuit.
Claim 3
Dependent Claim 44 words
A tuning arrangement as claimed in claim 1, characterized in that said one circuit having the highest resonant frequency is the resonant circuit of the oscillator circuit, and the coil limits the tuning range of said resonant circuit at a low frequency end thereof.
Claim 4
Dependent Claim 80 words
A tuning arrangement as claimed in claim 1 or 2, characterized in that the tuning range of the tuning arrangement comprises at least the standardized television frequency band VHF I and that the resonant frequency of the oscillator resonant circuit is located an order of magnitude of 40 MHz above the resonant frequency of the RF-circuit, the padding capacitor being of the order of magnitude of 120 pF and the coil being of the order of magnitude of 70 nH.

References Cited (Backward Citations)

US3354397A Cited
US3370254A Cited
US3611154A Cited
US3582791A Cited
US3889210A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1989-12-08 1990-06-09 1990-12-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1993-12-08 1994-06-09 1994-12-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1997-12-08 1998-06-09 1998-12-09 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag