Fine phase error-compensating system and method

Claim 2

In a system for compensating for the drifting of an alternating input signal from a predetermined phase relationship with respect to an alternating reference signal, the combination comprising: a. means for generating alternately positive-going and negativegoing voltage ramps during alternate half cycles of said input signal; b. means for producing a pair of voltage levels representative of the phase relationship between said reference signal and a signal derived at least partly from said input signal; and c. means for generating a bilevel signal whose value is changed between its two levels in response to alternate ones of said voltage ramps reaching alternate ones of said pair of voltage levels.

Claim 3

The combination of claim 1 further characterized in that said means for generating voltage ramps is comprised of a bipolar current source, a capacitor, and means for causing current to flow into and out of said capacitor from and to said bipolar current source during alternate half cycles of said input signal.

Claim 4

The combination of claim 1 further characterized in that said means for producing a pair of voltage levels representative of the phase relationship between said input signal and said reference signal includes: a. a phase comparator for producing a phase error signal which is representative of said phase relationship; and b. means for deriving from said signal a pair of voltage levels of equal magnitude by opposite polarity, with the potential difference between said voltage levels varying as a function of said phase error signal.

Claim 5

The combination of claim 3 wherein said means for deriving a pair of vOltage levels includes a differential amplifier.

Claim 6

The combination of claim 1 characterized further in that the signal which is derived from said input signal is in phase with said bilevel signal so that the phase relationship represented by said pair of voltage levels is that between the phase of said reference signal and the phase of said bilevel signal.

Claim 7

The combination of claim 1 characterized further in that the signal which is derived from said input signal is in phase with said input signal so that the phase relationship represented by said pair of voltage levels is that between the phases of said input signal and said reference signal.

Claim 8

In a system for compensating for the drifting of an alternating input signal from a predetermined phase relationship with respect to an alternating reference signal, the combination comprising: a. means for generating two series of voltage ramps, the ramps of the respective series being initiated during alternate half cycles of said input signal; b. means for producing a bilevel output signal with alternates between a pair of levels in response to the respective voltage ramps of said first and second series reaching alternate ones of the pair of voltage levels; and c. means for generating said voltage levels as a function of the relative phases of said output signal and said reference signal.

Claim 9

In a system for compensating for the drifting of an alternating input signal from a predetermined phase relationship with respect to an alternating reference signal, the combination comprising: a. means for generating two series of voltage ramps, the ramps of the respective series being initiated during alternate half cycles of said input signal; b. means for producing a bilevel output signal with alternates between a pair of levels in response to the respective voltage ramps of said first and second series reaching alternate ones of the pair of voltage levels; and c. means for generating said voltage levels as a function of the relative phases of said output signal and said reference signal.

Claim 10

The combination of claim 7 wherein said two series of voltage ramps are part of a single waveform whose value alternates between said pair of voltage levels.

Claim 11

The combination of claim 7 wherein said means for generating two series of voltage ramps includes: a. a bipolar current source; b. a capacitor; and c. means for charging and discharging said capacitor through said current source during alternate half cycles of said input signal so as to create alternately positive-going and negative-going voltage ramps across said capacitor.

Claim 12

The combination of claim 7 wherein said means for producing a bilevel output signal includes: a. a bistable signal source; and b. first and second threshold means, each for reversing the state of said bistable signal source in response to the voltage ramps of the respective ones of said series of voltage ramps reaching a predetermined relationship relative to a respective one of said voltage levels.

Claim 13

The combination of claim 7 wherein said means for generating said voltage levels includes: a. a phase comparator for producing a phase error signal which is representative of the relative phases of said output signal and said reference signal; and b. means for deriving from said error signal a pair of voltage levels of equal magnitude but opposite polarity.

Claim 14

The combination of claim 11 wherein said means for deriving said pair of voltage levels includes a differential amplifier receiving said error signal at its input and producing said pair of voltage levels at its outputs.

Claim 15

In a system for compensating for a change of a phase modulated composite color video waveform from a predetermined phase relationship with respect to an alternating reference signal, the combination comprising: a. means for generating two series of voltage ramps, successive ramps of the respective series being initiated in response to successive zero crossings of the video signal component of said composite color video waveform in a given direction; b. means for producing an alternating output signal which crosses zero in a given direction in response to successive ramps of one of said series reaching a first reference level and which crosses zero in the opposite direction in response to successive ramps of the other of said series reaching a second reference level; and c. means for generating said first and second reference levels as a function of the relative phases of said output signal and said reference signal.

Claim 16

In a system for compensating for a change of a phase modulated composite color video waveform from a predetermined phase relationship with respect to an alternating reference signal, the combination comprising: a. means for generating two series of voltage ramps, successive ramps of the respective series being initiated in response to successive zero crossings of the video signal component of said composite color video waveform in a given direction; b. means for producing an alternating output signal which crosses zero in a given direction in response to successive ramps of one of said series reaching a first reference level and which crosses zero in the opposite direction in response to successive ramps of the other of said series reaching a second reference level; and c. means for generating said first and second reference levels as a function of the relative phases of said output signal and said reference signal.

Claim 17

In a system for compensating for a change of a phase modulated composite color video waveform from a preDetermined phase relationship with respect to an alternating reference signal the combination comprising: a. means for generating two series of voltage ramps, successive ramps of a given one of said series being initiated in response to successive zero crossings of the video signal component of said composite color video waveform in a given direction; b. means for producing an alternating output signal which crosses zero in a given direction in response to successive ramps of a given one of said series reaching a first reference level, and which crosses zero in the opposite direction in response to successive ramps of the other one of said series reaching a second reference level, the magnitude of said reference levels being such that each zero crossing of said video signal component causes a corresponding, but delayed, zero crossing of said output signal; c. means for comparing the phase of that portion of the output signal which corresponds to the color burst carried by said composite color video waveform with the phase of said reference signal; and d. means responsive to said comparing means for producing said first and second reference levels as a function of the relative phases of the compared signal.

Claim 18

In a system for compensating for a change of a phase modulated composite color video waveform from a preDetermined phase relationship with respect to an alternating reference signal the combination comprising: a. means for generating two series of voltage ramps, successive ramps of a given one of said series being initiated in response to successive zero crossings of the video signal component of said composite color video waveform in a given direction; b. means for producing an alternating output signal which crosses zero in a given direction in response to successive ramps of a given one of said series reaching a first reference level, and which crosses zero in the opposite direction in response to successive ramps of the other one of said series reaching a second reference level, the magnitude of said reference levels being such that each zero crossing of said video signal component causes a corresponding, but delayed, zero crossing of said output signal; c. means for comparing the phase of that portion of the output signal which corresponds to the color burst carried by said composite color video waveform with the phase of said reference signal; and d. means responsive to said comparing means for producing said first and second reference levels as a function of the relative phases of the compared signal.

Claim 19

In a method for compensating for the drifting of an alternating input signal from a predetermined phase relationship with respect to an alternating reference signal the steps of a. generating two series of voltage ramps, one series in response to positive and the other in response to negative-going zero crossings of the input signal; b. generating an output signal having positive-going and negative-going zero crossings initiated in response to said first and second series of ramps reaching first and second preset voltage levels respectively; and c. altering said first and second voltage levels as a function of the phase of said output signal relative to the phase of said reference signal.

Claim 20

In a method for compensating for the drifting of an alternating input signal from a predetermined phase relationship with respect to an alternating reference signal the steps of a. generating two series of voltage ramps, one series in response to positive and the other in response to negative-going zero crossings of the input signal; b. generating an output signal having positive-going and negative-going zero crossings initiated in response to said first and second series of ramps reaching first and second preset voltage levels respectively; and c. altering said first and second voltage levels as a function of the phase of said output signal relative to the phase of said reference signal.