Video Mixer

This Circuit shows the GT4122 used as a two input video mixer. An evaluation PC board has been made and the artwork is included. Using this circuit, many of the critical circuit parameters can be measured including Crossfade Balance, Linearity, Bandwidth and Differential Gain and Phase. An output amplifier is shown but is only necessary when driving low impedance loads such as co-axial cables. The load on the GT4122 output itself should be kept above 5kW...

The GT4123 and GT4123A are the first dedicated single device, two input video mixer ICs available to the professional video and multimedia markets. Each input signal is applied to a conventional differential amplifier (AMP A and AMP B). From the amplifiers, the signals are applied to analog multiplier circuits (XA and XB) whose outputs are the product of the input signals and internally generated controlling voltages VCA and VCB...

The GT4124 is a broadcast quality monolithic integrated circuit specifically designed to linearly mix two video signals under the control of a third channel. Referring to the Functional Block Diagram, the input signals are applied to conventional differential amplifiers (AMP1 and AMP2) whose offsets are trimmed by on-chip resistors...

The modules described in this application note can be used as stand-alone multiplexers for both NTSC/PAL broadcast and any HDTV format applications. In addition, by virtue of their size, their performance and the SIP pin outs, they may be used to form larger n x m, professional video matrices. Each GX4201 device is a 1x1 video crosspoint characterised by a low distortion, unilateral signal path consisting of emitter followers at the input and output with level shifting circuits in between. ..