Ensemble Designs BrightEye 46 3G/HD/SD/ASI Electrical to Optical Converter - Manual (Page 12)

www.ensembledesigns.com BrightEye-12
3G/HD/SD/ASI Electrical to Optical Converter User Guide TM
BrightEye 46
EDH
Error Detection and Handling is a method to verify proper reception of an SDI or HD-SDI signal at the
destination. The originating device inserts a data packet in the vertical interval of the SDI signal and
every line of the HD signal which contains a checksum of the entire video frame. This checksum is
formed by adding up the numerical values of all of the samples in the frame, using a complex formula.
At the destination this same formula is applied to the incoming video and the resulting value is
compared to the one included in the transmission. If they match, then the content has all arrived with
no errors. If they don’t, then an error has occurred.
Embedded Audio
Digital Audio can be carried along in the same bitstream as an SDI or HD-SDI signal by taking
advantage of the gaps in the transmission which correspond to the horizontal and vertical intervals
of the television waveform. This technique an be very cost effective in transmission and routing, but
can also add complexity to signal handling issues because the audio content can no longer be treated
independently of the video.
Frame Sync
A Frame Synchronizer is used to synchronize the timing of a video signal to coincide with a timing
reference (usually a color black signal that is distributed throughout a facility). The synchronizer
accomplishes this by writing the incoming video into a frame buffer memory under the timing
direction of the sync information contained in that video. Simultaneously the memory is being read
back by a timing system that is genlocked to a house reference. As a result, the timing or alignment of
the video frame can be adjusted so that the scan of the upper left corner of the image is happening
simultaneously on all sources. This is a requirement for both analog and digital systems in order to
perform video effects or switch glitch-free in a router. Frame synchronization can only be performed
within a single television line standard. A synchronizer will not convert an NTSC signal to a PAL signal,
it takes a standards converter to do that.
Frequency Response
A measurement of the accuracy of a system to carry or reproduce a range of signal frequencies. Similar
to Bandwidth.
IEC
The International Electrotechnical Commission provides a wide range of worldwide standards. They
have provided standardization of the AC power connection to products by means of an IEC line cord.
The connection point uses three flat contact blades in a triangular arrangement, set in a rectangular
connector. The IEC specification does not dictate line voltage or frequency. Therefore, the user must
take care to verify that a device either has a universal input (capable of 90 to 230 volts, either 50 or 60
Hz), or that a line voltage switch, if present, is set correctly.
Interlace
Human vision can be fooled to see motion by presenting a series of images, each with a small change
relative to the previous image. In order to eliminate the flicker, our eyes need to see more than 30
images per second. This is accomplished in television systems by dividing the lines that make up
each video frame (which run at 25 or 30 frames per second) into two fields. All of the odd-numbered