Automatic AFT defeat circuit
AssigneeGTE Products Corporation
InventorJon L. Hoeft
Life of this patent
Estimating the term…
Abstract
A manual AFT switch and a manual FINE TUNE switch are configured so that whenever the FINE TUNE switch is engaged the AFT detector output is automatically disconnected from the AFT input of a tuning voltage control circuit. Furthermore a loading circuit coupled to the AFT input and driven by either the AFT switch or FINE TUNE switch assures the desired impedance at the AFT input whenever the output of the AFT detector is so disconnected. Automatically defeating the AFT circuit during manual fine tuning tends to optimize fine tuning by eliminating a component of correction voltage contributed by the AFT system, a face of which the lay viewer is likely to be unaware.
Claims12
An automatic AFT defeat circuit for a tuning voltage memory system having both AFT and FINE TUNING inputs, the defeat circuit comprising:
- a source of fine tuning voltage,
- a manual FINE TUNE switch having first and second sections, each with respective first, second and third terminals wherein the switch is so arranged and constructed that the first and second terminal of each section are connected when the FINE TUNE switch is activated and the second and third terminals are connected when the FINE TUNE switch is de-activated, and wherein:
- (1) the first terminal of the first section is connected to the FINE TUNING input,
- (2) the second and third terminals of the first section are connected to the source of FINE TUNING voltage,
- (3) the second terminal of the second section is connected to the AFT input, and
- (4) the third terminal of the second section is coupled to the output of an AFT detector.
An Automatic AFT Defeat circuit for a tuning voltage control system having AFT, Fine Tune Up and Fine Tune Down inputs, the defeat circuit comprising:
- a source of fine tuning voltage;
- a manual FINE TUNE switch having a first section comprising first, second, third and fourth terminals and having a second section comprising first and second terminals wherein the switch is so arranged and constructed that the first and second terminals of the first section are connected when the FINE TUNE switch is in the DOWN position, the third and fourth terminals of the first section are connected when the FINE TUNE switch is in the UP position and the first and second terminals of the second section are connected when the FINE TUNE switch is deactivated, and wherein:
- (1) the first terminal of the first section is connected to the Fine Tune Down input,
- (2) the second and third terminals of the first section are connected to the source of fine tuning voltage,
- (3) the fourth terminal of the first section is connected to the Fine Tune Up input,
- (4) the first terminal of the second section is connected to the AFT input, and
- (5) the second terminal of the second section is coupled to the output of an AFT detector.
In a tuning voltage memory system having both AFT and Fine Tuning inputs, the improvement comprising means for automatically defeating AFT operation during fine tuning conditions, said means including:
- a source of fine tuning voltage;
- a manual FINE TUNE switch having a first and second sections comprising respective first and second terminals, wherein the switch is so arranged and constructed that the first and second terminals of the first section are connected when the FINE TUNE switch is engaged and disconnected when the FINE TUNE switch is disengaed and the first and second terminals of the second section are disconnected when the FINE TUNE switch is engaged and connected when the FINE TUNE switch is disengaged and wherein;
- (1) the first terminal of the first section is connected to the Fine Tuning input,
- (2) the second terminal of the first section is connected to the source of fine tuning voltage,
- (3) the first terminal of the second section is connected to the AFT input, and
- (4) the second terminal of the second section is coupled to the output of an AFT detector.
Dependencies are inferred from the claim text.