Automatic signal-seeking circuitry

Claim 2

In frequency-modulated (FM) signal-receiving apparatus having a voltage-responsive tuner and a detected signal source responsive to signals from the tuner, a signal-seeking system comprising: a potential source; charging circuit means including a memory capacitor; potential follower means coupling said memory capacitor of said charging circuit means to said voltage-responsive tuner; potential coupling means for amplifying a signal from said detected signal source and applying a said amplified signal to said memory capacitor of said charging circuit means; a first pair of switching devices to effect an increasing frequency mode of said tuner by coupling said potential source to said charging circuit means and said potential-coupling means to a potential reference level to cause charging of said memory capacitor and upon receipt of a signal by said tuner decoupling said potential source from said charging circuit means and said potential-coupling means from said potential reference level whereby said potential-coupling means provides a drain path for said memory capacitor; and a second pair of switching devices for effecting a decreasing frequency mode of said tuner by selectively coupling and decoupling said memory capacitor of said charging circuit means and a potential reference level.

Claim 3

The signal-seeking system of claim 1 including a switching means coupled to said potential source and intermediate said potential-coupling means and a potential reference level whereby a reduction in potential from said potential source causes operation of said switching means opening the drain path of said memory capacitor whereupon the potential applied to said tuner remains substantially constant.

Claim 4

The signal-seeking system of claim 1 wherein said charging circuit means includes a charge capacitor in parallel connection with said memory capacitor intermediate one of said first pair of switching devices and a potential reference level.

Claim 5

The signal-seeking system of claim 1 wherein said charging circuit means includes a charge capacitor coupling one of said first pair of switching devices to a potential reference level and a series-connected impedance, unidirectional conduction device, and said memory capacitor in parallel connection with said charge capacitor.

Claim 6

The signal seeking system of claim 1 wherein said potential-coupling means includes a series-connected DC amplifier stage and unidirectional conduction device connected intermediate said detected signal source and said charging circuit means.

Claim 7

The signal-seeking system of claim 1 including an audio amplifier stage coupled to said detected signal source and responsive thereto for providing and applying an audio signal to said charging circuit means whereby rectified audio signals are applied to said memory capacitor to compensate for leakage thereof.

Claim 8

The signal-seeking system of claim 1 wherein said first pair of switching devices are ganged.

Claim 9

The signal-seeking system of claim 1 wherein said second pair of switching devices are ganged.

Claim 10

The signal-seeking system of claim 1 wherein said potential follower means is in the form of a high-input impedance electron device having a first electrode coupled to said potential source, a second electrode coupled to a potential reference level and to said voltage-responsive tuner, and a third electrode coupled to said charging circuit means.

Claim 11

The signal-seeking system of claim 2 including a threshold device coupling said switching means to said potential source.

Claim 12

In an FM signal receiver having a voltage-responsive tuner and a detector signal source, a signal-seeking system comprising in combination: a potential source; charging circuit means Including a charging capacitor connected to a potential reference level and a series-connected unidirectional conduction device and memory capacitor coupled in parallel with said charging capacitor; potential follower means coupling said memory capacitor of said charging circuit means to said voltage-responsive tuner; potential-coupling means including a series-connected amplifier stage and unidirectional conduction device DC coupling said detector signal source to said memory capacitor of said charging circuit means; audio amplifier means coupled to said detector signal source and AC coupled to said unidirectional conduction device of said charging circuit means; a first pair of switching devices for effecting an increased frequency mode of said tuner by coupling said potential source to said charging circuit means and said potential-coupling means to a potential reference level to effect increased charging of said memory capacitor and upon interception of a signal by said tuner decoupling said potential source from said potential source and said potential-coupling means from said potential reference level; and a second pair of switching devices for effecting a decreasing mode of said tuner by selectively coupling and decoupling said memory capacitor of said charging circuit means to a potential reference level.

Claim 13

In an FM signal receiver having a voltage-responsive tuner and a detector signal source, a signal-seeking system comprising in combination: a potential source; charging circuit means Including a charging capacitor connected to a potential reference level and a series-connected unidirectional conduction device and memory capacitor coupled in parallel with said charging capacitor; potential follower means coupling said memory capacitor of said charging circuit means to said voltage-responsive tuner; potential-coupling means including a series-connected amplifier stage and unidirectional conduction device DC coupling said detector signal source to said memory capacitor of said charging circuit means; audio amplifier means coupled to said detector signal source and AC coupled to said unidirectional conduction device of said charging circuit means; a first pair of switching devices for effecting an increased frequency mode of said tuner by coupling said potential source to said charging circuit means and said potential-coupling means to a potential reference level to effect increased charging of said memory capacitor and upon interception of a signal by said tuner decoupling said potential source from said potential source and said potential-coupling means from said potential reference level; and a second pair of switching devices for effecting a decreasing mode of said tuner by selectively coupling and decoupling said memory capacitor of said charging circuit means to a potential reference level.

Claim 14

The signal-seeking system of claim 11 including a unidirectional conduction device coupling said amplifier stage of said potential-coupling means to said potential source.

Claim 15

The signal-seeking system of claim 11 wherein said potential follower means is in the form of a metallized oxide silicon field effect transistor (MOSFET).

Claim 16

The signal-seeking system of claim 11 wherein said FM signal receiver is in the form of a television receiver and said detector signal source is in the form of an IF picture carrier detector signal source.

Claim 17

The signal-seeking system of claim 11 including a switching means coupled to said potential source and coupling said potential-coupling means to a potential reference level.

Claim 18

The signal-seeking system of claim 15 including a threshold device coupling said switching means to said potential source.