简要说明：VN31AX is a signal-unit color video noise meter for measuring video luminance noise, chroma AM noise

VN31AX is a signal-unit color video noise meter for measuring video luminance noise, chroma AM noise, and chroma PM noise of both NTSC and PAL video signals.
The input signal is continuously analyzed, and the NTSC or PAL circuitry is automatically selected and indicated via front panel LEDs.
Aside from full-field noise measurements, the VN31AX is capable of either odd-field or even-field measurements.
The measurement window function allows the user to select rectangular measurement windows ranging from a 4-?s line segment to a full field.
Features
Automatic selection of NTSC or PAL systems.
One device for luminance and chroma AM/PM noise measurements.
World's first "Any-Size, Anywhere" measurement window.
One-touch measurements via pre-programmed noise mode keys.
Automatic Level Control (ALC) for stable input levels.
Automatic sag compensation for uniform input signals.
User-defined judgment ranges for GO/NG evalutions.