The 1910 Digital Generator is a state-of-the-art test-signal generator designed for performance testing of NTSC video systems and equipment. The 1910 is especially suited where high accuracy and stability are required. It is also a VITS inserter (internal and external) with a full complement of signals that allow testing in studio, transmitter, production, or research environments. Four external VITS inputs permit insertion of signals such as videotext, closed captioning, source ID, and other similar sources. These four inputs may be converted to four pulse outputs for use in a production environment.
Test signals are stored as 10-bit digital words and converted to analog form by a 10-bit precision DAC (with deglitching to reduce differential gain and differential phase) to ensure signal accuracy as well as long-term stability and repeatability.
Since all signals are stored in replaceable EPROMs, changing needs and industry standards will not cause obsolescence.
Control and versatility of the 1910 are greatly enhanced by the use of its RS-232 control port. Most functions of the 1910 can be controlled, reconfigured, and saved. This includes VITS and full field signal selection, matrix signal creation, and sequences.
The 1910 offers full VITS and VIRS insertion capabilities which can be controlled through the RS-232 control port or through ground closures with the remote control unit. The 1910 may be used to insert either internally or externally generated test signals or data patterns in any combination on lines 10 through 20. Full sync and burst insertion capabilities with accurate SCH phasing eliminate the need for proc amps. When used as a VITS inserter, the program line is bypassed upon loss of incoming sync to prevent nonsynchronous VITS or sync insertion. The 1910 may be reconfigured so that transmitter protection may be enabled where the loss of incoming sync will automatically cause a test signal to be inserted on the program line to maintain sync continuity until normal operation is restored.
Four terminated inputs are standard in the 1910. Externally generated VITS from another source such as teletext, source ID, close captioning, etc., can be internally gated and inserted into the program. External VITS can be inserted on any field of lines 10 through 20 as selected by RS-232 control port or the remote control unit.
This included feature of the 1910 allows the user to change the four external VITS inputs to four pulse outputs. The outputs available are H Drive, V Drive, Composite Blanking, and Burst Flag. Composite sync and subcarrier outputs are always available.
The 1910 can also be used as a stand-alone signal source that will remain SCH phased and locked to an internal oven-controlled reference.
Remote control through a ground closure interface allows the user to control the full field signals, VITS insertion on lines 14 through 20 (VITS changes are saved in nonvolatile memory), VIR mode, bypass/operate, genlock source, control mode, and reset to a preprogrammed condition.
The 1910 can also be programmed and controlled through the RS-232 interface. Control could be through a RS-232 terminal, personal computer, or an automated measurement set such as the Tektronix VM700A, which would use the 1910 as a programmable signal source to stimulate and measure television equipment.
In addition to the functions available through ground closure control, the RS-232 port provides the ability to redefine the signal selection on the front panels to better meet particular user needs such as placing frequently used signals in a preferred position or in a convenient sequence for calibration, production testing, or other special uses.
The 1910 has an EEPROM nonvolatile memory (no need for battery backup) where configurations different from the factory set can be saved even if the instrument is powered down or a power failure occurs.
The 1910 has commands that allow the user to program the VITS or full field signals to be displayed for definable periods of time in specific sequences.
An example of color-frame sequence would be to set field