I was going through the datasheet of ADV7125 DAC and found this sentence confusing.
For optimum performance, the analog outputs should each have a source termination resistance to ground of 75 Ω (doubly terminated 75 Ω configuration). This termination resistance should be as close as possible to the ADV7125 to minimize reflections.
Well, what I think is - since the cable impedance is 75 ohms, and the load is also 75 impedance at the end of the cable, is n't the cable already devoid of reflections ? Then why adding that 75 ohms at the beginning (double termination) ??! Also suppose the cable impedance was 50 ohms in this case, what can we do to reduce reflection ?