Videotek VTM-2000 Specifications download pdf (Page 187)

Alarm Descriptions

VTM Series Installation and Operation Handbook

5-9

For example, assume that the Vertical Interval Test Signal of color bars on line 17,

field 2 is selected. Also, assume the line position is set to monitor the blue color packet

with a range of 5° and duration of 0 seconds. If the phase error between burst and the

blue vector point exceeds ± 5°, an alarm occurs.

Horizontal Blanking (H Blanking)

The Horizontal Blanking (H Blanking) alarm occurs when the time interval between

the end of active video and the start of active video violates the specified limits for a

period in excess of the duration setting. The limits are:

• NTSC: 10.7 to 11.1µs

• PAL: 11.8 to 12.2µs

For this measurement to be accurate, active video must be higher than 20 IRE (NTSC)

or 350 mV (PAL).

Vertical Blanking

The Vertical Blanking alarm occurs if the number of lines during the vertical blanking

period violates the selected width limit for a period in excess of the duration setting.

The selectable widths are 20 Lines to 25 Lines for NTSC and 25 to 30 Lines for PAL.

SC/H Phase

The SC/H Phase alarm occurs when the phase angle of burst compared to the 50%

point of the leading edge of horizontal sync on line 10 of field 1 (NTSC) or line 1

(PAL) exceeds the range setting for a period in excess of the duration setting. The

range is ± 5° to 90° in NTSC and ± 5° to 45° in PAL.

VITS

The VITS alarm occurs when the selected lines become active or inactive as set by the

amplitude threshold for a period in excess of the duration setting. One or more lines

can be monitored, and they do not have to be successive. For example, line 17/E can be

monitored for activity over 50 IRE while line 20/O is monitored for inactivity under 50

IRE. The threshold and duration settings are global.

Captioning

Closed Caption Not Detected - Analog

The Closed Caption Not Detected alarm is activated when the presence of a closed

caption data word on line 21(284) with valid parity bits is not detected in a composite

signal for a period in excess of the duration setting.

Closed Caption Not Updating - Analog

The Closed Caption Not Updating alarm is activated when closed caption carrier is

present and the data word on line 21 is null in a composite signal for a period in excess

of the duration setting.

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Videotek VTM-2000 Specifications Page 187