Manufacturing Automation Protocol; computer programs that run manufacturing automation systems. [Fib111]
Margin
The amount of signal in dB by which the satellite system exceeds the minimum levels required for operation. [Sat07]
Mary QAM
Mary QAM modulator with square lattice. The “M” refers to the integer number of points on the QAM constellation, i.e. the number of distinct states that can exist. The size of the QAM constellation is, where Symbol values in each dimension are:. The bitmap is Gray encoded. Symbols are normalized so that the average energy is 1. That is, normalized with . [Sou10]. As the order of the modulation increases, so does the number of points on the QAM constellation diagram. The various flavors of QAM may be used when datarates beyond those offered by 8PSK are required by a radio communications system. This is because QAM achieves a greater distance between adjacent points in the IQ plane by distributing the points more evenly. In this way the points on the constellation are more distinct and data errors are reduced. While it is possible to transmit more bits per symbol, if the energy of the constellation is to remain the same, the points on the constellation must be closer together and the transmission becomes more susceptible to noise. This results in a higher bit error rate than for the lower order QAM variants. In this way there is a balance between obtaining the higher data rates and maintaining an acceptable bit error rate for any radio communications system. [Rad11]
Integer Value of M

2^{k }(K = # of bits/symbol)

MQAM

Notes

2

1

2QAM

AKA “BPSK”

4

2

4QAM

AKA “QPSK”

8

3

8QAM

Nonsquare constellation

16

4

16QAM

Square constellation

32

5

32QAM

Nonsquare constellation

64

6

64QAM

Square constellation

128

7

128QAM

Nonsquare constellation

256

8

256QAM

Square constellation

512

9

512QAM

Nonsquare constellation

1024

10

1024QAM

Square constellation

2048

11

2048QAM

Nonsquare constellation

4096

12

4096QAM

Square constellation

8192

13

8192QAM

Nonsquare constellation

16384

14

16384QAM

Square constellation, AKA “16kQAM”

32768

15

32768QAM

Nonsquare constellation

65536

16

65536QAM

Square constellation, AKA “64kQAM”

Mass Splicing
Splicing of many fibers in a cable. [Fib111]
Master Antenna Television (MATV)
Antenna and distribution system which serves multiple dwelling complexes such as hotels, motels and apartments.
Master Headend
A headend that collects television program material from various sources by satellite, microwave, fiber, and other means, and distributes this material to Distribution Hubs in the same metropolitan or regional area. A master headend MAY also perform the functions of a distribution hub for customers in its own immediate area.
Master SRM
Master Session Resource Manager; a device employed in a cable operator’s headend or hub, usually with switched digital video (SDV), that allocates QAM bandwidth between video on demand (VOD) and SDV services. The Master SRM enables existing VOD QAMs to be pooled and shared between VOD and SDV servers.
Matching Transformer
A transformer designed to match the impedance of one circuit to that of another. [Arr11]
Material Dispersion
Dispersion resulting from the different velocities of each wavelength in a material. [Fib111]
MATV
Master Antenna Television; A distribution system that is usually contained within a single building and receives its signals from an antenna or CATV system. [Lin07]
MBaud
One million symbols of information per second. Equivalent to 1 Mbps for binary signals. [Fib111]
MBOFDM
Multiband Orthogonal Frequency Division Multiplexing; an efficient approach for ultrawideband (UWB) wireless communication applications. MBOFDM is a multiband technology, using orthogonal frequency division multiplexing. The total bandwidth that could be occupied, as defined by FCC, is from 3.1 GHz to 10.6 GHz. This covers a total span of 7.5 GHz. MBOFDM divides the available spectrum into 14 bands of 528 MHz. The first 12 bands are grouped into 4 band groups consisting of 3 bands, and the last two bands are grouped into a fifth band group. See diagram below. An OFDM symbol, transmitted in a 528 MHz band includes 100 data subcarriers, 10 guard subcarriers, and 12 pilot subcarriers for coherency and to provide robustness against frequency offsets and phase noise. Data sent over each data subcarrier are modulated, using QPSK or dual carrier modulation (DCM). Using QPSK, a symbol of 2 bits is mapped on a subcarrier. The DCM symbol has 4 bits. The same 4 bits of information are mapped onto two different subcarriers, separated by 50 subcarriers (approximately 206 MHz). With this separation, the probability that both points simultaneously suffer from fading decreases and diversity loss is reduced.
UWB Standard Spectrum Allocation Diagram courtesy of “A MBOFDM System Implemented in Matlab”, Revision 1.1, by Helena Sarmento, 19 July 2008
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