Ensemble Designs BrightEye 5 Analog Composite TBC and Frame Sync - Manual (Page 28)

www.ensembledesigns.com BrightEye 5 - Page 28
5 Analog Composite TBC and Frame Sync User Guide
Word Clock
Use of Word Clock to genlock digital audio devices developed in the audio recording industry. Early
digital audio products were interconnected with a massive parallel connector carrying a twisted pair
for every bit in the digital audio word. A clock signal, which is a square wave at the audio sampling
frequency, is carried on a 75 ohm coaxial cable. Early systems would daisychain this 44.1 or 48 kilohertz
clock from one device to another with coax cable and Tee connectors. On the rising edge of this Work
Clock these twisted pairs would carry the left channel, while on the falling edge, they would carry the
right channel. In most television systems using digital audio, the audio sample clock frequency (and
hence the ‘genlock’ between the audio and video worlds) is derived from the video genlock signal. But
products that are purely audio, with no video reference capability, may still require Word Clock.
WSS
Wide Screen Signaling is used in the PAL/625 video standards, both in analog and digital form, to
convey information about the aspect ratio and format of the transmitted signal. Carried in the vertical
interval, much like closed captioning, it can be used to signal a television receiver to adjust its vertical
or horizontal sizing to reflect incoming material. Although an NTSC specification for WSS exists, it
never achieved any traction in the marketplace.
YUV
Strictly speaking, YUV does not apply to component video. The letters refer to the Luminance (Y), and
the U and V encoding axes using in the PAL composite system. Since the U axis is very close to the B-Y
axis, and the V axis is very close to the R-Y axis, YUV is often used as a sort of shorthand for the more
long-winded “Y/R-Y/B-Y”.
Y/Cr/Cb
In digital component video, the luminance component is Y, and the two color difference signals are
Cr (R-Y) and Cb (B-Y).
Y/Pr/Pb
In analog component video, the image is carried in three components. The luminance is Y, the R-Y
color difference signal is Pr, and the B-Y color difference signal is Pb.