2
KRAMER ELECTRONICS LTD.
1
INTRODUCTION
Congratulations on your purchase of this Kramer Electronics SDI Switcher/Matrix. Since 1981, Kramer has
been dedicated to the development and manufacture of high quality video/audio equipment. The Kramer line
has become an integral part of many of the best production and presentation facilities around the world. In
recent years, Kramer has redesigned and upgraded most of the line, making the best even better. Kramer’s line
of professional video/audio electronics is one of the most versatile and complete available, and is a true leader in
terms of quality, workmanship, price/performance ratio and innovation. In addition to the Kramer line of high
quality switchers, such as the one you have just purchased, Kramer also offers a full line of high quality
distributors, processors, interfaces, controllers and computer-related products.
This manual includes configuration, operation and option information for the following products from the
Kramer line of SDI Switchers and Matrices. All of them are similar in operation and features.
SD-7308 – 8x1 SDI Switcher
SD-7388 – 8x8 SDI Matrix
SD-7316 – 16x16 SDI Matrix
1.1
A Word on Video Switchers and Matrices
A video switcher usually switches between several sources (inputs) and one or more acceptors (outputs). A
switcher that allows several inputs to be connected to several outputs simultaneously is called a Matrix
Switcher. Switchers may be of the electronic or mechanical type. Most matrices are of the active electronic type,
with many crosspoints. Vertical interval switching, frequently used in video, ensures that the transition from one
video source to another (such as switching between two genlocked cameras) is smooth and without interference.
The switching and changeover is done during the blanked vertical interval period, when the transition is hidden
from the eyes. Vertical interval switching is needed when recording or transmitting a video program involving
several video sources, as in live broadcast, to ensure clean, undisturbed picture transitions. The switched sources
should be genlocked. Some matrices have a special, additional input – a genlock input, which is used to genlock
the matrix to an external genlock or a studio master reference. Digital (SDI) matrices usually have an analog
genlock input, while very few of them offer an additional digital genlock input. Matrices and switchers may
sometimes be RS-232 or RS-485/422 controlled. Each of these options is a way of remotely controlling a
video/audio device (switcher etc.) using a PC with a serial port, or another device that uses a similar
communication protocol. The simplest connection between the RS-232 controller and the controlled device uses
two wires (TRANSMIT, RECEIVE) and a common ground wire.
1.2
Digital and Analog video signals
An
analog
signal varies continuously. It may have any value (within its physical bounds) and can change at
any instant. A
digital
signal is made up of a finite number of discrete levels, usually – but not always –
changing only at discrete time periods. An example of a digitized waveform is shown below.
ANALOG SIGNAL
DIGITAL SIGNAL