Video feedback matching circuit and method therefor
AssigneeMotorola, Inc.
InventorMary E. Gallagher
Life of this patent
Estimating the term…
Abstract
A circuit (10) for inserting a secondary video signal in a primary video signal. The primary and secondary video signals are combined forming a combined video signal having a primary video portion and a secondary video portion. The combined video signal is fed back to a feedback matching circuit (21) for measuring and comparing the phase, amplitude, and blanking level of a reference signal of the primary video portion and a reference signal of the secondary video portion of the combined video signal. The feedback matching circuit (21) makes an adjustment to the secondary video signal to reduce differences between the reference signals of the primary and secondary video portions of the combined video signal.
Claims18
A method for matching a secondary video signal to a primary video signal, the secondary video signal being inserted with the primary video signal forming a combined video signal, the combined video signal includes a primary video portion and a secondary video portion, the method comprising:
- feeding back the combined video signal to a feedback matching circuit for measuring a phase, amplitude, and blanking level of a reference signal of the primary video portion and measuring a phase, amplitude, and blanking level of a reference signal of the secondary video portion;
- comparing a measurement of said phase, amplitude, and blanking level of said reference signal of the primary video portion to a measurement of said phase, amplitude, and blanking level of said reference signal of the secondary video portion of the combined video signal;
- and
- adjusting the secondary video signal to match said phase, amplitude, and blanking level of said reference signal of the primary video portion.
A feedback matching circuit for matching a secondary video signal to a primary video signal, the secondary video signal being inserted into the primary video signal forming a combined video signal having a primary video portion and a secondary video portion, the feedback matching circuit comprising:
- an A/D (analog to digital) converter responsive to the combined video signal;
- a digital filter responsive to said A/D converter for separating luma and chroma signals of a reference signal of the primary video portion and of a reference signal of the secondary video portion;
- a control circuit responsive to said digital filter for comparing said phase, amplitude, and blanking level of said reference signals of the primary and secondary video portions.
A circuit for providing a secondary video signal matched relative to a primary video signal wherein the primary and secondary video signal are combined forming a combined video signal, comprising:
- an A/D (analog to digital) converter responsive to an alternate video signal for converting said alternate video signal to a digital format;
- a video DSP (digital signal processor) responsive to said A/D converter for processing said alternate video signal applied thereto and for providing the secondary video signal;
- a RAM for storing data;
- a RAM interface responsive to said video DSP and a control signal for interfacing said RAM to said video DSP;
- a feedback matching circuit responsive to a primary video portion and a secondary video portion of the combined video signal and said RAM interface for adjusting the secondary video signal to match relative to a phase, amplitude, and blanking level of a reference signal of said primary video portion;
- and
- a D/A (digital to analog) converter responsive to said feedback matching circuit for converting the secondary video signal from said digital format to an analog format.
Dependencies are inferred from the claim text.