UHF Hybrid tuner

• US 3,909,726 A
• Filed: 09/26/1973
• Issued: 09/30/1975
• Est. Priority Date: 09/26/1973
• Status: Expired due to Term

• Current Assignee: Pierre Dobrovolny, Stanley P. Knight
• Original Assignee: Pierre Dobrovolny, Stanley P. Knight
• Inventors: Dobrovolny, Pierre, Knight, Stanley P.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Psitos, Aristotelis M.
• Application Number:
  US05/400,772
• Time in Patent Office: 734 Days
• Field of Search: 325/352,357,452,457,459,462,464,465,318,445,451 317/234H,234UA 334/15 357/75,84
• US Class Current: 455/150.1
• CPC Class Codes: H03J 3/185 with varactors, i.e. voltage variable reactive diodes
• CPC Class Codes: H05K 9/006 specially adapted for signal processing applications, e.g. CATV, tuner, antennas amplifier

Abstract

A UHF television tuner includes a radio-frequency amplifier, a local oscillator and a mixer enclosed in a box-like housing within which is suspended an insulative substrate. A first conductive layer is disposed on the substrate in a disconnected pattern of a plurality of connective elements. A second layer of dielectric material overlies the first layer in a disconnected pattern. A third layer of conductive material overlies the second layer in a disconnected pattern that, together with the first and second layers, defines: (1) a variety of capacitive elements; (2) a variety of inductive elements; and (3) defines another plurality of connective elements. A fourth layer of resistive material is disposed in a disconnected pattern and interconnects different portions of the first and third layers, thereby completing the definition of all connective elements and defining the resistive elements. Active elements, such as varactor diodes, are mounted on the substrate in interconnecting relationship with the first and third layers. The different patterns of the various layers, together with a very few discrete components, including the active devices, serve to define a complete UHF tuner in a very small volume. Certain of the various patterns also form circuits that exhibit advantageous selectivity and tuning characteristics.

Claims

1. A UHF tuner comprising a box-like housing having walls of electrically conductive material and including a radio-frequency amplifier tunable to receive selected signals in the UHF spectrum, a local oscillator tunable to develop a mixing signal displaced in frequency from that of the selected signal by a constant amount and a mixer responsive to said amplified selected signal and said mixing signal for producing a constant-frequency intermediate signal, said amplifier, said oscillator and said mixer being composed of inductive, capacitive, resistive, connective and active elements, the improvement in said inductive, capacitive, resistive and connective elements comprising:

a substrate, of non-magnetic electrically insulating material, supported within said housing;

a first layer of electrically conductive material disposed on said substrate in a disconnected pattern defining a plurality of said connective elements;

a second layer of at least one dielectric material overlying said first layer in a disconnected pattern;

a third layer of electrically conductive material overlying said second layer in a disconnected pattern defining with said first and second layers said capacitive elements, forming at least a portion of said inductive elements, and defining another plurality of said connective elements;

a fourth layer of at least one resistive material disposed in a disconnected pattern interconnecting different portions of said first and third layers to complete the definition of said resistive and connective elements; and

means mounting said active elements on said substrate in interconnective relationship with said first and third layers.

2. A tuner as defined in claim 1 which includes a plurality of electrically conductive planar shields disposed perpendicularly to said substrate and individually oriented between adjacent ones of said amplifier, mixer and oscillator, said shields being effectively connected to adjacent portions of said third layer.

3. A tuner as defined in claim 2 in which different ones of said shields are disposed respectively above and below said substrate.

4. A tuner as defined in claim 2 in which a tab portion of at least one of said shields overlies at least one of said inductive elements defined by said third layer and is adjustable in position toward and away from said substrate for trimming the response frequency determineD by that inductive element.

5. A tuner as defined in claim 2 in which an additional shield, parallel to the other shields, is disposed between the input and output portions of said amplifier.

6. A tuner as defined in claim 1 in which said amplifier includes an input section having a plurality of inductive elements spaced apart in succession with each one being mutually coupled to the next, said plurality of inductive elements being defined by a succession of strips of said third layer forming a single-tuned input circuit.

7. A tuner as defined in claim 6 in which five inductive elements are included in said plurality of inductive elements, the first of said inductive elements having its lower end connected to receive said broadband signals and its upper end connected to the upper end of the fourth element and capacitively coupled to the fifth and third elements, the lower ends of the second, third and fourth elements being connected in common, the upper ends of said third and fifth elements being connected together and the upper end of the second element being connected to a varactor adjustable in determination of the tuning of said input section.

8. A tuner as defined in claim 7 in which one of said capacitive elements is coupled between taps located on said first and said second of said inductive elements.

9. A tuner as defined in claim 1 in which said amplifier includes an output section having a double-tuned resonator with frequency-selective coupling networks, said output section being composed of a pair of spaced mutually-coupled inductive elements connected at one end to a common ground and capacitively coupled at their other ends;

a third inductive element mutually coupled to at least one of said pair and conveying signals from the output of said section;

means for coupling input signals to said section across a first one of said pair of inductive elements; and

a pair of commonly-tuned varactors individually coupled across respective ones of said inductive elements in said pair.

10. A tuner as defined in claim 1 in which said amplifier includes an output section having a double-tuned resonator with frequency-selective coupling networks, said section exhibiting reduced signal response at a frequency one-half said constant frequency and at the image of the frequency difference between the frequencies of said broadband signal and said mixing signal.

11. A tuner as defined in claim 1 in which said amplifier, oscillator and mixer each include resonant circuits defined by portions of said third layer and in which said portions are closed upon themselves along the walls of said box.

12. A tuner as defined in claim 1 in which at least one of said inductive elements includes a strip of said third layer a portion of which is folded back toward itself, thereby defining a substantially magnetically and electrically self-contained closed-loop inductor.

13. A tuner as defined in claim 12 in which a portion of said second layer defines at least one capacitor intercoupling opposing ends of the folded strip and establishing resonance therewith.