M

Microwave Hop - A microwave RF connection between MTSO and cell sites in remote locations.

Mixer - The circuit or component in a superhet receiver where the oscillator signal is combined with the incoming carrier signal.

MIN1 - The 24-bit number which corresponds to the 7-digit subscriber telephone number.

MIN2 - The 10-bit number that corresponds to the 3-digit subscriber area code.

MMI - Man/Machine Interface - how easy a phone is to use, how fun, how sexy. As phones conform to strict standards, the MMI becomes a key area of differentiation.

Mobile Coverage Area - Geographical area in which two-way radio service can be expected (between base station and mobile unit).

Mobile-ID - The 7 digit mobile telephone number. Does not include area code.

Mobile Attenuation - The power of the mobile can be adjusted (or attenuated) dynamically to one of seven discrete power levels (analog cellular). This is done so that when a mobile comes closer to a base receiver its power is reduced to prevent the chance of interfering with other mobiles operating on the same voice channel in another cell (co-channel interference). Additionally, this is even more important to portable units to keep the transmit power at a minimum to increase the talk usage time before the batteries expire.

Mobile Origination - The initiation of a telephone call by a mobile unit.

Mobile unit - The mobile unit is either a handheld or car mounted transceiver. The mobile unit connects the user to the base station via RF (radio frequency). The mobile unit is also known as the "Subscriber".

MSA - Metropolitan Service Area. A cellular coverage, defined by the FCC, which resides in a densely populated area. here are 306 MSAs in the United States, all of which now have cellular service.

MSC - Mobile Switching Centre. Interface between the base station system and the switching subsystem of the mobile phone network.

MSPS - Megasamples per second. Sampling rate for analog to digital converters.

MSS - Mobile Satellite Service.

MTSO - Mobile Telephone Switching Office. The switching office that all base station cell sites connect to. It is a sophisticated computer that monitors all cellular calls, keeps track of the location of all cellular-equipped vehicles traveling in the system, arranges hand-offs, keeps track of billing information, etc. he MTSO in turn interfaces to the PSTN by connection to a CO.

MU-Law (U-Law) - An encoding format for the quantization and digitization of analog signals into Pulse Code Modulation (PCM) signals (A/D) and recovery of analog signals from PCM (D/A). U-Law specifies the parameters for compression and re-expansion of the signals during signal transmission and processing. U-Law PCM encoding is used in North America. A-Law is the European format.

Multipath - The presence of multiple signals arriving at the receiver antenna simultaneously. Signals that are in phase will add to one another. Signals that are out of phase will cancel one another.

Multipath fading - Multipath fading A.K.A. Rayleigh fading occurs when the direct-path transmitted wave destructively interferes with it's reflections at the receiving end. The destructive interference is a result of the reflected waves arriving at the receiving end out of phase with the direct-path transmitted wave. Multipath interference can vary in intensity depending on the amount of destructive interference that takes place.

Multiple Access - A method for accomodating more users in the same frequency band.