A Differential Dual Integrated Circuit Video If with Built-in AGC for Color Television

Abstract

This paper explains a new video IF amplifier for color television incorporating a high performance integrated circuit and a discrete output transistor. The integrated circuit (XC1352P) functions in two capacities: first as a unilateralized 50db gain IF amplifier with 65db usable AGC range; and second as a gated keyer and AGC amplifier with delayed AGC output for the tuner. The discrete transistor (MPS6544) with low Cre; functions as an un-neutralized output stage driving the detectors. Overall sensitivity is 250μV rms at 44MHz for 3V detected output (70db power gain). Admittance variations with AGC are negligible, leaving the in-channel pass band and adjacent channel rejection independent of AGC. The above characteristics indicate that video IF amplifiers superior to those used today can be made by incorporating both the XC1352P and MPS6544. Encapsulation of the dual function integrated circuit in a single 14 pin dual in-line plastic package will bring the overall cost of these functions down to competitive prices.