Chrominance signal gain control circuit

A chrominance signal control circuit in a color television apparatus, comprising:

• amplifying means of a gain control type for selectively amplifying a composite signal including a burst signal and a chrominance signal, the gain thereof being controllable as a function of a control voltage input, and, selectively, as a function of a control pulse input,
• means for providing a pulse signal having a pulse width and a phase time encompassing the burst signal of said composite signal,
• means receiving the selectively amplified composite signal output of said amplifying means and responsive to the pulse signal from said pulse signal providing means for extracting the burst signal from the selectively amplified composite signal,
• means for receiving and peak detecting the extracted burst signal and supplying the peak detected burst signal output thereof to said amplifying means as the control voltage input,
• means receiving the selectively amplified composite signal output of said amplifying means and providing a peak detected output of the chrominance signal only, of said composite signal, when the peak detected chrominance signal output exceeds a predetermined value, and
• means responsive to the burst extracting pulse signal for producing a control pulse output having a pulse width and a phase time encompassing the burst signal of said composite signal, and responsive to the peak detected chrominance signal output for automatically adjusting the magnitude of the control pulse output thereof and supplying the control pulse to said amplifying means for selectively controlling the gain of said amplifying means during said phase time encompassing the burst signal of said composite signal, such that an increase of said peak detected chrominance signal output adjusts the magnitude of the control pulse output to increase the gain of said amplifying means for selective amplification of the burst signal, and the control voltage produced in accordance with the peak detected burst signal output reduces the gain of said amplifying means, thereby to afford peak color control of the selectively amplified, composite signal output of said amplifying means.

A chrominance signal control circuit in a color television apparatus, comprising:

• band pass amplifying means of a gain control type having a first input for receiving the composite signal comprising a burst signal and a chrominance signal, and a second input for receiving both a control voltage and a control pulse input for control of the gain thereof,
• means for providing a pulse signal having a pulse width and a phase time encompassing the burst signal of said composite signal,
• means receiving the selectively amplified composite signal output of said amplifying means and responsive to the pulse signal from said pulse signal providing means for extracting the burst signal from the selectively amplified composite signal,
• means for receiving and peak detecting the extracted burst signal and supplying the peak detected burst signal output thereof to said amplifying means as the control voltage input thereto
• means receiving the composite signal output of said amplifying means and providing a peak detected of the chrominance signal only, of said composite signal output, when the peak detected chrominance signal output exceeds a predetermined value, and
• means responsive to the burst extracting pulse signal for producing a control pulse output and receiving the peak detected chrominance signal output for automatically adjusting the magnitude of the control pulse output thereof and supplying the control pulse as said control pulse input to said amplifying means for selectively controlling the gain thereof for selective amplification of the burst signal, thereby to afford peak color control of the selectively amplified, composite signal output of said amplifying means.