Sony DVW-250 - Manual (Page 3)

The DVW-250/250P is a portable videocassette
recorder in the Digital Betacam series. It allows
recording and playback of sound and picture in the
Digital Betacam format.
The following are some of the features of the DVW-
250/250P.
Flexible input/output interfaces
The unit is designed to accept either analog video
(component/composite) and audio signals, or Dl
format serial digital video/audio signals. It is therefore
highly suitable for use not only in analog systems but
also in all-digital systems.
Analog input signals pass through the built-in A/D
converter, and are converted to 10-bit digital video
signals and 20-bit digital audio signals. Similarly,
both digital and analog output signals are provided, for
flexible support of mixed analog-digital systems.
Simple system configuration using the serial
digital interface
The serial digital inputs to the SDI (Serial Digital
Interface) connector provide for one video signal and
four audio channels through a single BNC connector.
When connected to other digital equipment, this makes
setting up and transporting, for example on outside
assignments, extremely straightforward.
High quality digital recording
This unit records both sound and vision on the tape in
the Digital Betacam format (see the figure at the end of
this page). Since all internal processing is digital,
signal outputs are stable, and reproduction is very
accurate.
Designed for field operations
The unit is compact and lightweight (main unit
approximately 6.6 kg or 14 Ib 8 oz), making it ideal for
carrying and operating in the field. The power
consumption while recording is about 26 W (with the
MODE switch in the SAVE position and the CONFI
switch in the OFF position), and the optional battery
pack provides about two hours of continuous
recording.
High speed search with color picture
The search speed can be set to 2 times, 5 times or 8
times normal speed. Using rewind or fast forward, a
color playback signal is available at 24 times normal
speed, making tape cuing both fast and accurate.
Two LCD units for ease of operation
The front panel includes two LCDs: the smaller shows
the unit status and time indications, and the larger
displays the audio level meters, the video level meters,
or the setup menu.
By switching the display mode, it is possible to change
the audio level indications for fine adjustment in a
narrower range.
Backlighting is provided to make the displays easier to
read in gloomy conditions.
Overview
The Digital Betacam format is based on the
conventional Betacam and Betacam SP formats, and
allows high-performance digital recording and
playback.
One of the features of the Digital Betacam format is
the introduction of a new technique known as
"coefficient recording," which allows the data rate of
the video signal to be reduced to approximately half.
This makes 120 minutes or more of recording possible
with an "L" size cassette.
The compressed video signal includes error-correcting
codes (ECC), which correct the signal on playback.
This powerful error-correcting system provides the
improved signal reliability which is another feature of
the Digital Betacam format.
Recording format
The processing of the Digital Betacam video signal
conforms to the Dl 4:2:2 component digital format,
with digitization according to ITU-R BT. 601.
The following figure shows schematically the Digital
Betacam recording format on the tape. A set of six
diagonal tracks contains one field of video and four
channels of audio information.
Chapter 1 Overview I- I