Vertical detail enhancement on/off switch

Claim 2

A circuit comprising: a transistor having first, second and third electrodes; first means for applying an input signal to said first electrode; second means for connecting said second electrode to a point of reference potential; third means connected to said third electrode for developing an output signal; a feedback path connected between said first and third electrodes and including a charge storage device connected in series with a variable impedance device; a source of supply potential; a switch operated variable impedance means connected between said source of supply potential and the junction between said storage device and said variable impedance device, said variable impedance means providing a first impedance for a first switching condition and a second impedance for a second switch condition; and said first switching condition causing said variable impedance device to assume a first impedance value and said second switching condition causing said variable impedance device to assume a second impedance value; whereby said output signal is substantially reduced during said second switching condition and said junction remains at substantially the same D.C. value during transitions from said first to said second switching condition.

Claim 3

The circuit according to claim 1 wherein said charge storage device comprises a capacitor.

Claim 4

The circuit according to claim 2 wherein said variable impedance device comprises a diode.

Claim 5

The circuit according to claim 3 wherein said switch operated variable impedance means comprises a switch connected in series with a fist resistor and a second resistor connected in parallel with said switch and first resistor, the resistance value of said first resistor being substantially smaller than the resistance value of said second resistor.

Claim 6

In a color TV receiver apparatus having a signal path for providing a vertial detail enhancement signal, a user activated circuit for substantially reducing the amplitude of said vertical detail enhancement signal, said circuit comprising: a transistor having first, second and third electrodes; means for applying said enhancement signal to said first electrode; means for connecting said second electrode to a point of reference potential; means connected to said third electrode for developing an amplified version of said enhancement signal; a feedback path including a charge storage device connected in series with a variable impedance device between said first and third electrodes; a source of supply potential; a switch operated variable impedance means connected between said source of supply potential and the junction between said charge storage device and said variable impedance device, said variable impedance means providing a first impedance for a first switching condition and a second impedance for a second switching condition; and said first switching condition causing said variable impedance device to assume a first impedance value and said second switching condition causing said variable impedance device to assume a second impedance value; said amplified version of said enhancement signal being substantially reduced during said second switching condition and said junction remaining at substantially the same D.C. value during transitions from said first to said second switching condition.

Claim 7

In a color TV receiver apparatus having a signal path for providing a vertial detail enhancement signal, a user activated circuit for substantially reducing the amplitude of said vertical detail enhancement signal, said circuit comprising: a transistor having first, second and third electrodes; means for applying said enhancement signal to said first electrode; means for connecting said second electrode to a point of reference potential; means connected to said third electrode for developing an amplified version of said enhancement signal; a feedback path including a charge storage device connected in series with a variable impedance device between said first and third electrodes; a source of supply potential; a switch operated variable impedance means connected between said source of supply potential and the junction between said charge storage device and said variable impedance device, said variable impedance means providing a first impedance for a first switching condition and a second impedance for a second switching condition; and said first switching condition causing said variable impedance device to assume a first impedance value and said second switching condition causing said variable impedance device to assume a second impedance value; said amplified version of said enhancement signal being substantially reduced during said second switching condition and said junction remaining at substantially the same D.C. value during transitions from said first to said second switching condition.

Claim 8

The circuit according to claim 5 wherein said charge storage device comprises a capacitor.

Claim 9

The circuit according to claim 6 wherein said variable impedance device comprises a diode.

Claim 10

The circuit according to claim 7 wherein said switch operated variable impedance means comprises a switch connected in series with a first resistor and a second resistor connected in parallel with said switch and first resistor, the resistance value of said first resistor being substantially smaller than the resistance value of said second resistor.

Claim 11

In a color TV receiver apparatus having a signal path for providing a vertical detail enhancement signal, a user activated circuit for substantially reducing the amplitude of said vertical detail enhancement signal, said circuit comprising: a transistor having base, emitter, and collector electrodes; means for supplying said enhancement signal to said base electrode; means for connecting said emitter electrode to a point of reference potential; means providing a vertical detail enhancement signal utilization circuit connected to said collector electrode; said transistor being biased to provide an amplified version of said enhancement signal at the collector electrode; a feedback path including a capacitor and a diode connected in series in the order named between the base and collector electrodes with the cathode of said diode connected to said collector electrode; a source of supply potential coupled to said collector electrode via a first resistor; the series combination of a normally open switch and a second resistor connected between said source and the junction between said capacitor and said diode; a third resistor connected between said source and said junction; the value of said second resistor being substantially smaller than the value of said third resistor; said third resistor providing a charging path for said capacitor and having a value such that said diode is just forward biased when said switch is opened; said amplified version of said enhancement signal being substantially reduced when said switch is closed and said junction remaining at substantially the same D.C. level during transitions of said switch from said normally open to said closed position.

Claim 12

In a color TV receiver apparatus having a signal path for providing a vertical detail enhancement signal, a user activated circuit for substantially reducing the amplitude of said vertical detail enhancement signal, said circuit comprising: a transistor having base, emitter, and collector electrodes; means for supplying said enhancement signal to said base electrode; means for connecting said emitter electrode to a point of reference potential; means providing a vertical detail enhancement signal utilization circuit connected to said collector electrode; said transistor being biased to provide an amplified version of said enhancement signal at the collector electrode; a feedback path including a capacitor and a diode connected in series in the order named between the base and collector electrodes with the cathode of said diode connected to said collector electrode; a source of supply potential coupled to said collector electrode via a first resistor; the series combination of a normally open switch and a second resistor connected between said source and the junction between said capacitor and said diode; a third resistor connected between said source and said junction; the value of said second resistor being substantially smaller than the value of said third resistor; said third resistor providing a charging path for said capacitor and having a value such that said diode is just forward biased when said switch is opened; said amplified version of said enhancement signal being substantially reduced when said switch is closed and said junction remaining at substantially the same D.C. level during transitions of said switch from said normally open to said closed position.