Auto-tint circuit for a TV receiver

Claim 2

In a TV receiver including a source of first and second quadrature related color mixture signals, means for automatically altering the color represented by such first and second signals when they correspond to a prescribed range of colors comprising: first detection means responsive to said first and second signals for producing the magnitude of the vector sum thereof; second detection means responsive to said first and second signals for producing a signal corresponding to the instantaneous angle of said vector sum; means responsive to said angle signal for generating the sines and cosines thereof and for angles in said prescribed range of colors generating the sines and cosines of adjusted angles; and means for multiplying said sines and cosines by said magnitude to produce first and second altered quadrature related color mixture signal.

Claim 3

An auto-tint circuit in a color TV receiver, having a source of quadrature related color mixture signals I and Q, for generating corrected quadrature related signals I' and Q', comprising: means responsive to the I and Q signals for generating a signal corresponding to the magnitude of the vector sum of the I and Q signals; means responsive to the I and Q signals for generating a signal corresponding to the angle θ between the vector sum of the I and Q signals and the axis of one of the I and Q signals; means responsive to the signal corresponding to said angle θ for generating signals corresponding to the cosines and sines of an angle φ where φ is a function of θ for the angle θ occurring in a prescribed range of angles, and φ equals θ otherwise; means responsive to the signal corresponding to said magnitude and to the signals corresponding to the cosines and sines of angle φ for generating the products of the magnitude times the cosines corresponding to the corrected signal I' and the products of the magnitude times the sines corresponding to the corrected signal Q'.

Claim 4

An auto-tint circuit in a color TV receiver, having a source of quadrature related color mixture signals I and Q, for generating corrected quadrature related signals I' and Q', comprising: means responsive to the I and Q signals for generating a signal corresponding to the magnitude of the vector sum of the I and Q signals; means responsive to the I and Q signals for generating a signal corresponding to the angle θ between the vector sum of the I and Q signals and the axis of one of the I and Q signals; means responsive to the signal corresponding to said angle θ for generating signals corresponding to the cosines and sines of an angle φ where φ is a function of θ for the angle θ occurring in a prescribed range of angles, and φ equals θ otherwise; means responsive to the signal corresponding to said magnitude and to the signals corresponding to the cosines and sines of angle φ for generating the products of the magnitude times the cosines corresponding to the corrected signal I' and the products of the magnitude times the sines corresponding to the corrected signal Q'.

Claim 5

The auto-tint control circuit set forth in claim 2 wherein the means for generating signals corresponding to the sines and cosines of angle φ comprises a memory element having an address input port coupled to receive the signals corresponding to the angle θ and programmed to produce at an output port thereof the sines and cosines of the angles applied as address signals, and programmed to produce the sines and cosines of color corrected angles when the address angles θ fall with said prescribed range.

Claim 6

The auto-tint circuit set forth in claim 2 further including means responsive to the signals θ for applying a static adjustment to the angle θ under user control, to produce an adjusted angle θ' corresponding to a static tint adjustment, and which adjusted angles are applied to the means for generating sines and cosines.

Claim 7

The auto-tint circuit set forth in claim 2 further including means responsive to the signal corresponding to the magnitude of said vector sum and a gain control signal for linearly adjusting the value of said magnitude, said adjusted magnitude signal being applied to the means for generating the products of the magnitude times the sines and cosines.

Claim 8

The auto-tint circuit set forth in claim 2 wherein the angle φ in said prescribed range is given φ=θ-K sin 2θ where K is a predetermined constant.

Claim 11

A color TV receiver including a source of first and second color mixture signals, a first ROM responsive to ratios of said signals for producing signals corresponding to the angle of the vector sum of said signals relative to a reference, and including a second ROM coupled to said first ROM and programmed for producing signals corresponding to trigonometric ratios of angle signals applied thereto, wherein one of said first and second ROM's is programmed non-linearly over a predetermined range of angles processed therein to effect auto-flesh correction.

Claim 12

A color TV receiver including a source of first and second color mixture signals, a first ROM responsive to ratios of said signals for producing signals corresponding to the angle of the vector sum of said signals relative to a reference, and including a second ROM coupled to said first ROM and programmed for producing signals corresponding to trigonometric ratios of angle signals applied thereto, wherein one of said first and second ROM's is programmed non-linearly over a predetermined range of angles processed therein to effect auto-flesh correction.