Atec Tektronix-VM700T - Manual (Page 2)

a modem to report measurement
results or control a signal router.
A relative to reference mode
allows normalizing to a signal
source or eliminate signal path
errors from the desired
measurement. Up to 2 video
references can be stored in
NVRAM. Additionally, after
downloading to a PC through the
VM700T FTP driver, the video
reference can be uploaded to
another VM700T for reuse. A
running averaging mode can be
used to reduce the effect of noise.
When additional measurement
data is required a user can custom
configure measurement parameters
and report format.
A powerful Test Signal search
capability quickly and automati-
cally locates and identifies valid
test signals required for a selected
measurement, eliminating the
annoying and time consuming
task of manually locating
test signals.
Digital waveform monitor/
vectorscope
The VM700T Waveform mode
application provides real time
graphics displays of the video
signal allowing many additional
measurements to be made manu-
ally. Easy to use measurement
cursors are available to measure
time, frequency and amplitude
parameters of a video signal. These
cursors allow a very quick and
precise location of the 10%, 50%
and 90% points on any transi-
tion. Cursor mode also employs
an automatic calculation in the
wave shape in the center of the
display. The parameters calculated
are sine peak-to-peak amplitude,
frequency, and offset from blanking
level. This is very useful for
frequency response measurements
with the Multiburst signal.
The waveform display can be
expanded around any point both
vertically and horizontally. Since
the data is digitized, the display
remains bright and easy to ready
at all expansion factors. The
scales automatically expand with
the waveform, so all units are
correct as displayed. A channel
difference mode (A-B, A-C, B-A,
B-C, C-A, and C-B) is also provided.
A screen memory selection
enables Envelope mode, which
is useful for looking at teletext,
Jitter, or other changes over time.
Vector mode provides the normal
vectorscope display. The vectors
may be rotated or expanded,
with the rotation angle and gain
values displayed numerically on
the screen.
A unique “Find ColorBars”
feature searches all video for
ColorBars and displays the
vectors if found. The vectors can
be referenced to either the
selected channel’s burst or the
burst of one of the other two
channels or continuous subcarrier.
The phase difference between
the selected channel and the
reference is always displayed.
Select Line in both Waveform
and Vector modes can be used
to quickly specify any line for
display or automatic measurement
if it is the proper signal.
Picture mode
The signal source can be quickly
verified using the picture display.
Additionally, a “bright-up” line
select mode allows a user to
select any video line for use in
Measure mode or for viewing in
Waveform or Vector mode.
User programmable functions
Function mode is an extremely
powerful feature that allows a
user to store a sequence of user
operations as a macro function
for later “playback.”
For example, a set of measure-
ments (complete with hardcopy
commands) to be made on a
transmitter demodulator video
output, could be stored as a
function labeled “DEMOD.” The
function “playback” could then
be initiated manually, remotely
or completely automatically as a
user specified timed event. Function
files can be stored as a text file
on a PC for editing, copying or
uploading to another VM700T.
Other function capabilities
include controlling of external
serial devices such as video/audio
routers, switchers, signal
generators, telephone modems
and many other devices which
support RS232 communications.
Hardcopy
All information on the screen
may be printed in high resolution
graphics on printers supporting
PostScript ® , Hewlett-Packard ®
LaserJet™, DeskJet™, and
ThinkJet™, or 24-pin Epson ®
graphics via the Centronics
compatible parallel port or
standard RS-232C interface.
Automatic measurement results
in text format can be printed on
most ASCII printers using the
parallel or serial ports.
Remote Operation
The VM700T has a powerful and
fully documented remote control
language. The VM700T can thus
be operated from a remote terminal
via RS-232C to monitor unattended
transmission systems. In addition,
all files can be uploaded to a
main computer, and downloaded
to other VM700Ts. Two different
protocols are supported: FTP
(File Transfer Protocol) and
TELNET. The user can also select
a “no protocol” mode of the
RS-232C interface when dealing
with low baud rates. However,
file transfers can only take place
with FTP.
Specifications
The performance requirements
cited in this section are valid
only within the following
environmental limits:
Temperature range of 0 to 50
degrees Celsius, with a
minimum warm-up time of 20
minutes. The following tables
list each measurement and its
performance requirement.
The range specifies the extremes
between which a measurement
can be made.
All measurement accuracies
specified are valid only with
nominal input signals of 1 volt
pk-pk (± 6 dB) with an unweighted
signal-t-noise ratio of at least
60 dB on the incoming signal
and a termination accuracy of
± 0.025% (Tektronix PN 011-
0102-01 or equivalent).
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