Non-linear aperture correction circuit

Claim 2

In a disc record player for information recovery of video and sound signals, an apparatus including: means for recovering modulated information signals including composite color video signals with sound accompaniment from a disc record, said recovery means having a non-linear response which produces intermodulation products between said video and sound signals; means for demodulating said information signals; means, coupled to said demodulating means, for processing said demodulated signal; and means, connected to said recovery means, for providing compensation for said intermodulation products produced by said recovery means, said means for providing compensation comprising: a signal shaping circuit connected to said recovery means including; means for reducing the level of the modulated information signals and for providing a resistive source impedance; means for rejecting a signal of a given frequency; and means for shifting the phase of the modulated information signals; an amplifier; a non-linear signal path connecting the output of said signal shaping circuit to the input of said amplifier; and a linear signal path connected in parallel arrangement with said non-linear path.

Claim 3

The apparatus in accordance with claim 1 wherein said means for reducing includes a voltage divider having first and second resistive elements; wherein said means for rejecting includes a trap filter connected in parallel combination with said second resistive element of said voltage divider, said trap filter comprising first and second reactive elements; and wherein said means for shifting includes a thhird reactive element, connected in parallel combination with said trap filter; said third reactive element in combination with said first reactive element of said trap filter effecting a phase shift of said sound signals, and, said third reactive element in combination with said first resistive element of said voltage divider effecting an integration of said video signals.

Claim 4

The apparatus in accordance with claim 2 wherein said linear signal path effects a differentiation of the video signals which pass therethrough; said differentiation being complementary to said integration effected in said signal shaping circuit.

Claim 5

The apparatus in accordance with claim 3 further comprising an emitter follower transistor connected to said signal shaping circuit.

Claim 6

The apparatus in accordance with claim 4 further comprising a high pass filter, connected to said signal shaping circuit, for reducing low frequency noise.

Claim 7

In a disc record player for information recovery of video and sound signals, an apparatus including: means for recovering modulated information signals including composite color video signals with sound accompaniment from a disc record, said recovery means having a non-linear response which produces intermodulation products between said video and sound signals; means for demodulating said information signals; means, coupled to said demodulating means, for processing said demodulated signals; and means, connected to said recovery means, for providing compensation for said intermodulation products produced by said recovery means, said means for providing compensation comprising: a first non-linear signal path for transferring signals recovered from said recovery means; a second non-linear signal path for transferring signals recovered from said recovery means; a linear signal path for transferring signals recovered from said recovery means; means for inverting the polarity of the signal which passes through said first non-linear path; and means for summing the output signals from said first non-linear signal path, said second non-linear signal path and said linear signal path.

Claim 8

In a disc record player for information recovery of video and sound signals, an apparatus including: means for recovering modulated information signals including composite color video signals with sound accompaniment from a disc record, said recovery means having a non-linear response which produces intermodulation products between said video and sound signals; means for demodulating said information signals; means, coupled to said demodulating means, for processing said demodulated signals; and means, connected to said recovery means, for providing compensation for said intermodulation products produced by said recovery means, said means for providing compensation comprising: a first non-linear signal path for transferring signals recovered from said recovery means; a second non-linear signal path for transferring signals recovered from said recovery means; a linear signal path for transferring signals recovered from said recovery means; means for inverting the polarity of the signal which passes through said first non-linear path; and means for summing the output signals from said first non-linear signal path, said second non-linear signal path and said linear signal path.

Claim 9

The apparatus according to claim 6 wherein said inverting means comprises a transistor and wherein said transistor is coupled to a diode, said diode providing a non-linear impedance in response to the amplitude of the signal from said recovery means; said non-linear impedance affecting the gain of said transistor in a non-linear fashion.

Claim 10

In a disc record player for information recovery of video and sound signals, an apparatus including: means for recovering modulated information signals including composite color video signals with sound accompaniment from a disc record, said recovery means having a non-linear response which produces intermodulation products between said video and sound signals; means for demodulating said information signals; means, coupled to said demodulating means, for processing said demodulated signals; and means, connected to said recovery means, for providing compensation for said intermodulation products produced by said recovery means, said means for providing compensation comprising: an emitter follower transistor; means for combining; a first non-linear signal path connecting the emitter electrode of said emitter follower to an input of said amplifier; said first non-linear signal path comprising a first diode; and a second non-linear signal path connected to an input of said amplifier; said second non-linear signal path including an inverter transistor having a second diode connected thereto, said second diode altering the gain of said inverter transistor in a non-linear fashion; a bias means, connected to the anode of said second diode, providing equal bias current to said first and second diodes; said means for combining being used to sum the signals passing through said first non-linear signal path with the signals passing through said second non-linear signal path.

Claim 11

In a disc record player for information recovery of video and sound signals, an apparatus including: means for recovering modulated information signals including composite color video signals with sound accompaniment from a disc record, said recovery means having a non-linear response which produces intermodulation products between said video and sound signals; means for demodulating said information signals; means, coupled to said demodulating means, for processing said demodulated signals; and means, connected to said recovery means, for providing compensation for said intermodulation products produced by said recovery means, said means for providing compensation comprising: an emitter follower transistor; means for combining; a first non-linear signal path connecting the emitter electrode of said emitter follower to an input of said amplifier; said first non-linear signal path comprising a first diode; and a second non-linear signal path connected to an input of said amplifier; said second non-linear signal path including an inverter transistor having a second diode connected thereto, said second diode altering the gain of said inverter transistor in a non-linear fashion; a bias means, connected to the anode of said second diode, providing equal bias current to said first and second diodes; said means for combining being used to sum the signals passing through said first non-linear signal path with the signals passing through said second non-linear signal path.

Claim 12

The apparatus according to claim 8 wherein said bias means comprises a potentiometer.

Claim 13

The apparatus according to claim 9 further comprising: a resistor coupled between the cathode of said second diode and the anode of said first diode; a first capacitor coupling the cathode of said second diode to a first point of reference potential; a second capacitor coupling the emitter of said emitter follower to the cathode of said first diode; and a third capacitor coupling the anode of said first diode to said input of said amplifier.