B C D
E F G
H I J
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Q R S
T U V
Manual iris. A lens
with a manual method of varying the size of the aperture.
Matrix. A mathematical
array. A logical network configured in a rectangular array of
intersections of input/output
Matrix switcher. A
device for switching more than one camera, VCR, video printer and
similar, to more than one monitor,
VCR, video printer and similar. Much more
and more powerful than simple video
MATV. Master Antenna
MB. Megabyte. Unit
of measurement for computer memory consisting of approximately one
million bytes. Actual value
is 1,048,576 bytes. Kilobyte × Kilobyte = Megabyte.
MB/s. Megabytes per
second. Million bytes per second or 8 million bits per
written as MBps.
Mb/s. Megabits per
second. Million bits per second. Also written as Mbps.
One million hertz.
Microwave. One definition
refers to the portion of the electromagnetic spectrum that ranges
between 300 MHz and 3000 GHz.
The other definition is when referring
to the transmission
media where microwave links are
used. Frequencies in microwave
transmission are usually
between 4 GHz and 60 GHz.
MOD. Minimum Object
Distance. Feature of a fixed or a zoom lens that indicates the
distance an object can be from
the lens's image plane, expressed in meters.
Zoom lenses have
MOD of around 1 m, while fixed
lenses usually much less, depending
on the focal length.
Modem. This popular
term is made up of two words: MOdulator and DEModulator. The
function of a modem is to connect
a device (usually computer) via an audio (usually) telephone
line to another device with a modem.
It converts the digital computer signal to audio
Modulation. The process
by which some characteristic (i.e., amplitude, phase) of one wave
(carrier wave) is varied in accordance
with another wave (modulating or message signal).
An unwanted effect that appears in the video picture when a
(lines close together) pattern
is looked at with a CCD camera that has a pixel pattern close to
(but lower) the object pattern.
video. A video signal that represents the brightness values
(luminance) in the picture, but
not the colour values (chrominance).
MPEG. Motion Picture
Experts Group. An ISO group of experts that has recommended
manipulation of digital motion
images. Today there are a couple of MPEG
of which the most well known are
MPEG-1 and MPEG-2. The latter
one is widely accepted
for high definition digital television,
as well as multimedia
MPEG-1. Standard for
compressing progressive scanned images with audio. Bit rate is
1.5 Mbps up to 3.5 Mbps.
MPEG-2. The standard
for compression of progressive scanned and interlaced video signals
with high quality audio over a
large range of compression rates with a range
of bit rates from
1.5 to 100 Mbps. Accepted
as a HDTV and DVD standard of video/audio
Multiplexing. In CCTV it is correctly
Time Division Multiplexing and is the technique
used to enable a number of video inputs (up to 34) to
be recorded onto a single tape. Frequency
Division Multiplexing is a technique used to allocate
individual frequencies within a band of
frequencies. In fibre Optic systems there is
Wavelength Division Multiplexing WDM, and
Dense Wavelength Division Multiplexing DWDM where a
of wavelengths of light can
share the same fibre, to enable more information to