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067-1011-00 DSG
SECTION 1
SPECIFICATION
Product Description
The 067-1011-00 Digital Sweep Generator (DSG) is designed to
support the Performance Check and Adjustment procedures of the
Tektronix 1900 Digital Test Signal Generator.
The Digital Sweep
Generator provides a 10-bit digital data signal to drive the 1900
digital-to-analog converter (DAC) or any other video DAC
compatible with the proposed ·sMPTE standard ("Digital Video
Format for a Parallel Interface (System M/NTSC), July, 1979)
digital video interface, generating a swept-frequency sinewave
test signal.
The Digital Sweep Generator permits the division of
an A/D - D/A pair to make frequency domain measurements on the
D/A alone.
Future digital processing equipment will require
separation of A/D and D/A frequency response characteristics as
part of the calibration and performance check procedures.
When
used in conjunction with a 1900 and an 015-0408-00 Peak-to-Peak
Detecto~,
the Digital Sweep· Generator provides an NBS-traceable
analog frequency response standard, and is part of an effort to
provide NBS-traceable performance verification of Tektronix
television generators, waveform monitors, and other television
equipment (See Fig.
2-11).
The Digital Sweep Generator provides 10-bit, 14.31818 MHz (Mega
samples per second) word data derived from a cosine lookup table
stored in three PROMs.
To generate digital data representing a
55.9 kHz sinewave, all 256 words stored in the PROMs are used.
Digital
d~ta
representing higher frequencies is generated by
decreasing the number of words per sinewave.
The DIGITAL DATA
OUTPUT of the 067-1011-00 provides digital data to sweep a DAC
from 55.93 kHz to 7.159 MHz in each field by increments of 55.93
kHz every two lines of active video.
A front-panel
switched-variable control also permits an operator to manually
vary the digital data used to generate a CW signal.
Because the
DIGITAL DATA OUTPUT supplies non-composite digital data, the
Digital Sweep Generator provides a BLANKING output which may be
used to enable sync and burst insertion by the 1900.
It also
provides a BLACK BURST OUTPUT to which the 1900 may be genlocked.
The Digital Sweep Generator may be locked to the 1900 through the
DIGITAL CLOCK INPUT connector which uses the TRS and Clock
signals from the 1900 DIGITAL OUTPUT.
A separate MARKER output
provides identification of nominal 1-MHz intervals during the
sweep, and also provides nominal 3.58 MHz and 4.43 MHz markers.
1-1
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