VIDEO STANDARDS:
It is helpful to be aware of the standards for video waveforms and the parameters that are
used in professional S video. The main reason for measuring in I.R.E. Units instead of Volts
peak-to-peak is simplicity of the numbers created while measuring an S video signal. For
instance a correct amplitude video signal in Volts peak-to-peak and I.R.E. Units measure exactly:
VIDEO COMPONENT
I.R.E. UNITS
VOLTS peak-to-peak
Y (Luminance and Sync)
140
1.000000000----------
C
(Chrominance)
40
0.285714286----------
Y
(Sync
Pulse
only)
40
0.285714286----------
C
(Color
Burst
only)
40
0.285714286----------
All professional S video measurement is made in terms of I.R.E. UNITS. The I.R.E.
UNIT gets its name from the INSTITUTE of RADIO ENGINEERS that developed the standard
"I.R.E. UNIT" for S video measurement used in the United States, Canada and elsewhere.
A perfect S video signal will have a sync pulse of 40 I.R.E. units, the peak picture
Luminance amplitude would have 100 I.R.E. units, so a standard one volt black and white peak-
to-peak S video signal is 140 I.R.E units (40 SYNC + 100 LUMINANCE (WHITE). Both of
these signals comprise the “Y“ or Luminance channel of the S video signal. The minimum
bandwidth of this signal is 4.8MHz but can have significant energy at much higher frequencies.
The color channel of an S video signal is normally 40 I.R.E. units in amplitude at
3.58MHz in frequency. Color-Burst signals and CHROMINANCE in the picture are 40 I.R.E.
units when the video is at 100% saturated color. This color information is phase shifted to
convey the color information. The phase relationship between the Color Burst and the
Chrominance dictates the true color and the amplitude of the Chrominance conveys the color
brightness. An important bit of information here is that color pictures have a maximum peak-to-
peak output of 140 I.R.E. peak-to-peak “Luminance” and “Chrominance“ together.
The portable battery operated CM-1 Camera Master, with the CM-1S adapter can
measure Sync Pulse, Picture amplitude, overall Composite Sync, Picture Focus, and Color Burst
amplitude in I.R.E. units, on any 75 Ohm unbalanced S video signal.
MOUNTING THE CM-1S ADAPTOR:
Position the CM-1 facing toward you with its BNC (female) connectors facing upward.
Place the CM-1S adaptor above the connectors with the BNC (male) connectors facing down.
Line up the BNC connectors to mate. Rotate the BNC (male) connectors so that the notches align
with the BNC (female) connectors. Gently push the adaptor onto the meter and rotate the collars
on the BNC (male) connectors to lock both of them into place. To remove the adaptor simple
reverse this process.
CM-1Sisb
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