Back to results
US 5,285,179 AGranted
Double tuned circuit with balanced output and image trap
AssigneeThomson Consumer Electronics, Inc.
InventorsLeroy S. Wignot, Michael A. Pugel
Life of this patent
Estimating the term…
Abstract
Conversion of an RF signal amplifier from an unbalanced signal configuration to a balanced signal configuration is provided while including an image trap for both sides of the balanced circuit. The grounded side of the secondary of a double tuned circuit is lifted from ground to provide a balanced circuit configuration. A trap filter is provided in the balanced circuit configuration by a pair of small capacitors coupled between the balanced secondary leads to appropriate signal nodes.
Claims5
In a television signal processing apparatus, tuning apparatus, comprising:
- means for amplifying RF signals and having an output coupled to a signal node with respect to a reference potential,
- a first tuned circuit including a first varactor diode responsive to a first tuning voltage and a first inductance element coupled from the signal node to a point of reference potential for selecting one of said amplified RF signals in response to the first tuning voltage,
- a second tuned circuit including a second varactor diode responsive to a second tuning voltage and a second inductance element for further selecting said one of said amplified RF signals in response to the second tuning voltage,
- said first and second tuned circuits forming a double tuned circuit, said first and second inductance elements being inductively coupled,
- the second inductance element having a pair of output terminals balanced with respect to the reference potential,
- a first trap capacitor coupled between one output terminal of the second inductance element and the signal node, and
- a second trap capacitor coupled between the other output terminal of the second inductance element and the reference potential,
- the first and second trap capacitors providing a notch frequency for the tuned RF signal at each of the pair of output terminals.
5 more elements
Dependencies are inferred from the claim text.