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This paper establishes the quantitative relation between a TV transmitter load VSWR and the system frequency response. The need for a low value of VSWR is stressed, particularly for multimode transmitting systems.

Comparison between bandwidth-limited input pictures and output pictures from current generation TV transmitters show little difference except for faint edge ringing at an approximate 1-MHz rate. This is shown to be due to lack of specification and control of transmitter and receiver lower sideband attenuation and phase characteristics in the region around 1 MHz below visual carrier. Some observed and some calculated results are presented for comparison.

Certain transmitter adjustments are customarily made by optimizing performance as measured at the output of a visual demodulator. For reasons discussed in the text, demodulators used at the transmitter must have different design characteristics than typical home receivers. As a consequence, picture quality on the station monitor may be somewhat different than that seen on the average home receiver. The differences are described in the paper. Even if the transmitter were adjusted with typical receiver performance in mind, it is shown that the best transmitter adjustment for one receiver would not be the best for receivers designed with different selectivities and/or different envelope delays.