DBM may refer to dBm , a unit for power measurement dbm , UNIX s Database Manager family of pre relational database engines D. B. M. Patnaik 1925 2009 , an Indian lawyer, politician and communist leader De Bellis Multitudinis , a wargame ruleset Department of Budget and Management , the executive department in the Philippines Dibenzoylmethane , an aromatic diketone 1,3 diphenylpropane 1,3 dione Dibromomethane , a halomethane disambiguation de DBM it DBM sr DBM ... more details
For other uses DBM disambiguation DBM lowercase title dBm File Relationship between dBu and dBm.svg thumb A schematic showing the relationship between dBu the voltage source and dBm the power dissipated as heat by the 600 resistor dBm sometimes dBmW is an abbreviation for the power ratio in decibel ... the ratio between two values, such as signal to noise ratio . Unit conversions Zero dBm equals one milliwatt. A 3 dB increase represents roughly doubling the power, which means that 3 dBm equals roughly 2 mW. For a 3 dB decrease, the power is reduced by about one half, making 3 dBm equal to about 0.5 milliwatt. To express an arbitrary power P as x dBm, or vice versa, the following equations may ... or, math P 10 x 30 10 , math where P is the power in W and x is the power ratio in dBm. Below is a table summarizing useful cases class wikitable dBm level Power Notes 80 dBm 100 kW Typical ... dBm 1 kW 1000 W Typical combined radiated RF power of microwave oven elements Maximum RF output power from a ham radio transceiver allowed without special permission 50 dBm 100 W Typical Black ... RF power from a ham radio High frequency HF transceiver 40 dBm 10 W Typical PLC Power Line Carrier Transmit Power 37 dBm 5 W Typical maximum output RF power from a handheld ham radio VHF UHF transceiver 36 dBm 4 W Typical maximum output power for a Citizens band radio station 27 MHz in many countries 33 dBm 2 W Maximum output from a UMTS 3G mobile phone Power class 1 mobiles Maximum output from a GSM850 900 mobile phone 30 dBm 1 W 1000 Milliwatt mW Typical RF leakage from a microwave oven ... is US only. 27 dBm 500 Milliwatt mW Typical cellular phone transmission power Maximum output from a UMTS 3G mobile phone Power class 2 mobiles 26 dBm 400 Milliwatt mW 25 dBm 316 Milliwatt mW 24 dBm 250 Milliwatt mW Maximum output from a UMTS 3G mobile phone Power class 3 ... . The former is EU only, the latter is US only. 23 dBm 200 Milliwatt mW Equivalent isotropically ... more details
lowercase About the family of database engines DBM disambiguation DBMdbm was the first of a family of simple database engine s, originally written by Ken Thompson and released by AT&T in 1979. The name is a three letter acronym for database manager . dbm stores arbitrary data by use of a single key a primary key in fixed size bucket computing buckets and uses hash function hashing techniques to enable fast retrieval of the data by key. The hashing scheme used is a form of extendible hashing , so that the hashing scheme expands as new buckets are added to the database, meaning that, when nearly empty, the database starts with one bucket, which is then split when it becomes full. The two resulting child buckets will themselves split when they become full, so the database grows as keys are added. While dbm and its derivatives are pre relational database s effectively a Associative array hash fixed to disk in practice they can offer a more practical solution for high speed storage looked up by key as they do not require the overhead of connecting and preparing queries. This is balanced by the fact that they can generally only be opened for writing by a single process at a time. While this can be addressed by the use of an agent Daemon computer software daemon which can receive signals ... dbm has had many successors Ndbm In 1986 Berkeley produced ndbm standing for New Database Manager ... margo papers usenix91 paper.ps ref gdbm standing for GNU dbm ref http www.gnu.org.ua software ... vsdb VSDB An implementation of a dbm like database written by John Meacham that supports full ... Cabinet A straightforward implementation of DBM, released under the GPL also by Mikio Hirabayashi in 2009. ref name Hirabayashi profile https sourceforge.net projects aodbm aodbm An append only DBM ... author Brachman & Neufeld title TDBM A DBM Library With Atomic Transactions url http tdbm.dss.ca papers ... Structured storage de DBM Datenbank fr Dbm ja DBM lv Dbm ru DBM zh Dbm ... more details
Multiple issues unreferenced October 2009 orphan March 2010 distinguish Database marketing Databased marketing is an approach to marketing a way of doing business that systematically, objectively analyzes how a Customer base behaves over time. Databased Marketing DBM allows practitioners to think and act strategically about Customer retention and Customer loyalty loyalty . DBM is a Customer measurement and feedback system that provides insight into Customer behaviour why they do what they do to all levels of an organization. The insights generated by DBM are used to continuously align all activities, products services, processes to its high value or best Customers. DBM is the analytic side of Customer focus, or putting Customers at the core of everything we do organizing around the Customer. The core concepts of DBM grew out of the Mail order catalog sales industry and have been refined over the last sixty years. Yet, the concept is poorly understood by today s managers. The term databased is somewhat misleading, making novices believe that DBM is a technology . By databased we mean fact based , facts about Customers, really facts about what they are doing. DBM can be done without any special software and does not require lots of data . Category Marketing techniques ... more details
In a telecommunications system , a transmission level point TLP is a test point or interface, i.e. a physical point in an electronic circuit where a test Signalling telecommunication signal may be inserted or measured, and for which the nominal power physics power of the test signal is specified. A zero dBm transmission level point or synonym zero transmission level point is a transmission level point where the nominal test signal power is 0dBm. In practice, the abbreviation TLP is usually used, and it is modified by the nominal level for the point in question. For example, where the nominal level is 0 dBm , the expression 0 dBm TLP, or simply, 0TLP, is used. Where the nominal level is 16 dBm, the expression 16 dBm TLP, or 16TLP, is used. The nominal transmission level at a specified TLP is a function of system design and is an expression of the design gain or loss. Voice channel communications channel transmission levels, i.e. TLPs, are usually specified for a frequency of approximately 1,000 Hz. The TLP at a point at which an end instrument , e.g. a telephone set, is connected is usually specified as 0 dBm . References FS1037C MS188 See also Alignment level Telecomm stub Category Telecommunications ... more details
orphan date January 2010 Dielectric breakdown model DBM is a macroscopic mathematical model combining the diffusion limited aggregation model with electric field . It was developed by Niemeyer, Pietronero, and Weismann in 1984. It describes the patterns of dielectric breakdown of solids, liquids, and even gases, explaining the formation of the branching, self similar Lichtenberg figure s. External links http classes.yale.edu fractals Panorama Physics DLA DBM DBM.html Dielectric Breakdown Model Category Electricity phys stub ... more details
The decibel watt or dBW is a unit for the measurement of the strength of a signal expressed in decibel s relative to one watt . It is used because of its capability to express both very large and very small values of power in a short range of number, e.g. 1 milliwatt 30 dBW, 1 watt 0 dBW, 10 watts 10 dBW, 100 watts 20 dBW and 1,000,000 W 60 dBW. math mbox Power in dBW 10 log 10 mbox Power in W math Compare dBm , which is referenced to one milliwatt 0.001 W . Certain dBW value in dBm is always 30 more because 1 watt is 1000 milliwatts, and ratio of 1000 in power is 30 dB, e.g. 10 dBm 10 mW is equal to 20 dBW 0.01 W . Although the decibel dB is permitted for use alongside SI units, the dBW is not. See also dBm Category Sound Electronics stub sound tech stub measurement stub nl Decibelwatt pl DBW ... more details
RDBM may refer to Relational database management system RDBMS Reliable database manager , a journaled layer on top of Cdb software cdb Remote DBM , the networked interface to AnyDBM Reyes del Bajo Mundo , a Salvadoran hip hop group disambig ... more details
orphan date January 2009 In telecommunication , standard telegraph level STL is the Power physics power per individual telegraph channel communications channel required to yield the standardization standard composite data level. For example, for a composite data level of 13 dBm at 0 dBm transmission level point 0TLP , the STL would be approximately 25 dBm for a 16 channel VFCT terminal telecommunication terminal computed from STL 13 10log sub 10 sub n , where n is the number of telegraph channels and the STL is in dBm. References FS1037C MS188 Category Data transmission Category Telegraphy ... more details
Psophometric voltage is a Electronic circuit circuit noise voltage measured with a psophometer that includes a CCIF 1951 weighting filter weighting network . Psophometric voltage should not be confused with psophometric emf, i.e. , the emf in a generator or line electrical engineering line with 600 internal resistance. For practical purposes, the psophometric emf is twice the corresponding psophometric voltage. Psophometric voltage readings, V , in millivolts, are commonly converted to dBm psoph by dBm psoph 20 log sub 10 sub V 57.78. References FS1037C Category Electrical parameters Category Noise Category Telecommunications terms electronics stub telecomm term stub ... more details
In telecommunication , reference noise is the magnitude of Telecommunication circuit circuit noise chosen as a reference for measurement. Many different levels with a number of different weightings are in current use, and care must be taken to ensure that the proper parameters are stated. Specific ones include A weighting dBa , dBa F1A , dBa HA1 , dBa0, dBm , dBm psoph , dBm0 , dBrn , dBrnC , dBrnC0, dBrn f sub 1 sub f sub 2 sub , dBrn 144 line , dBx. References FS1037C MS188 Category Noise Category Communication circuits Category Telecommunications terms telecomm term stub ... more details
De Bellis Multitudinis DBM Lang en Of the Wars of the Multitude is a ruleset for table top miniatures wargames for the period 3000 BC to 1485 AD. It is the big battle development of De Bellis Antiquitatis . ref Phil Barker in Slingshot 258 p 33 ref As its name implies, it is aimed primarily at simulating large battles. The rules allow armies to be chosen from published Army Lists in 4 books, with about 250 different army lists in total but many more once all the in list variants are taken into account using a points system to select roughly equal armies if required. History DBM was written by the UK based Wargames Research Group WRG team of Phil Barker , Richard Bodley Scott and Sue Laflin Barker. De Bellis Multitudinis De Bellis Magistrorum Militum DBMM is Phil Barker s intended successor to DBM . DBM evolved from the earlier De Bellis Antiquitatis rule set, adapted to play larger games with more figures, comparable in size to games played using the then popular 7th Edition WRG Ancient rules. DBM expanded on DBA s definition troop types by function defining troops as bladesmen rather than Roman legionaries for example by adding grades for each. Grades such as Superior, Ordinary and Inferior ... on it varies by formation type skirmishers or psiloi in DBM terminology have 2 men per base, cavalry ... believable outcomes in the main. For command and control, DBM extended the Player Initiative Point ... unfavorably contrasted with other rules. ref eg Slingshot 207 p22 DBM VERSUS ARMATI, Brian Mischel ref Community As well as friendly games, DBM competitions are played worldwide including ... The successor to DBM is De Bellis Magistrorum Militum. DBM grew out of DBA and retained its geometric ... DBM, the combat system is a good deal more complicated with a large number of modifiers. One reviewer ... 272 p50 ref External links The DBM community is global, a good starting point is author Richard ... Wargames Research Group Publisher of DBM Notes reflist Category Miniatures games de De Bellis ... more details
mA 20 mA 0 dBm 96 dBm 28.5 mm x 14 mm Oct, 2007 rowspan 5 Serial Peripheral ... downfiles Module AN 2400 13 v1 0 RN.pdf manual 3 A 54 mA 26 mA 11 dBm 101 dBm 48.3 mm x 14 mm Oct, 2007 http www.microchip.com stellent idcplg?IdcService SS GET ... mA 22 dBm 101 dBm 36 mm x 14 mm Oct, 2007 http www.microchip.com stellent idcplg ... 0 dBm 94 dBm 17.8 mm x 27.9 mm http www.microchip.com stellent idcplg?IdcService ... litv pdf swrz003 errata integral 18 mA 20 mA 0 dBm 26 mm x 20 mm Mar, 2008 ... 17 dBm to 3 dBm rowspan 2 101 dBm 18.8 mm x 13.5 mm x 2.0 mm rowspan ... 23 mA rowspan 2 Up to 20 dBm rowspan 2 104 dBm rowspan 2 38 mm x 13.5 mm x ... documents doc8168.pdf datasheet RF output 26 mA 11 mA Up to 11 dBm 110 dBm 24 ... or U.FL U.FL connector 0.3 A 44 mA 35 mA 6.1 dBm 97 dBm 25.4 mm x ... 4 kB 60 kB PCB trace 3.0 A, 1 A 150 mA 42 mA 20 dBm 92 dBm 25 mm x 36 mm May, 2008 UART rowspan 2 http www.freescale.com webapp sps site overview.jsp ... rowspan 3 20 dBm 100 dBm 25.4 mm x 36.5 mm http www.cel.com pdf press cl403p.pdf ... mA rowspan 2 37 mA rowspan 2 97 dBm rowspan 2 25 mm x 33 mm rowspan 2 2009 UART , Serial ... 2 8 bit, 8051 rowspan 2 8 kB rowspan 2 5 A 50 mA rowspan 2 27 mA 10 dBm rowspan 2 92 dBm rowspan 2 23 mm x 29 mm rowspan 2 May, 2008 rowspan 2 UART rowspan ... pdf brochures LSMatrixProductSheet.pdf brochure 130 mA 20 dBm rowspan 2 http www.nivis.com ... Connector rowspan 2 15 A rowspan 2 60 mA rowspan 2 21 mA rowspan 2 10 dBm rowspan 2 98 dBm rowspan 2 20 mm x 25 mm 2009 rowspan 2 UART , Serial Peripheral Interface ... dBm rowspan 4 94 dBm rowspan 4 16.5 mm x 29.2 mm x 3.5 mm rowspan 4 2008 rowspan ... more details
dBm sub ISOI sub dBm sub G sub dB sub P sub out,f,dBm sub P sub in,f,dBm sub ISOI sub dBm sub OSOI sub dBm sub P sub out,2f,dBm sub 2P sub in,f,dBm sub 2ISOI sub dBm sub OSOI sub dBm sub P sub in,2f,dBm sub 2P sub in,f,dBm sub ISOI sub dBm sub P sub out,2f,dBm sub 2P sub out,f,dBm sub OSOI sub dBm ... P out,f,dBm P out,2f,dBm math math bigtriangleup SO,dB ISOI dBm P in,f,dBm math math bigtriangleup SO,dB OSOI dBm P out,f,dBm math See also Intermodulation Intercept Point Third order intercept point ... more details
Unreferenced date August 2007 The Precise Tone Plan specification for the North America n network defines the Call progress tone s used for standard signaling in the PSTN . The tones are as follows dial tone is a continuous tone having frequencies of 350 and 440 hertz Hz at a level of 13 dBm ringback tone is defined as comprising frequencies of 440 and 480 hertz Hz at a level of 19 dBm and a cadence of 2 seconds ON and 4 seconds OFF busy tone is defined as having frequency components of 480 and 620 hertz Hz at a level of 24 dBm and a cadence of half a second ON and half a second OFF reorder tone , also called fast busy tone, contains the same frequency components as busy tone at a similar level but with a cadence of 0.25 of a second ON and 0.25 of a second OFF Prior to the Precise Tone Plan, devices used other frequencies and levels. Such tones generated by older telephone exchange equipment did not follow the Precise Tone Plan and were either formed as dual frequency tones or equivalently as ring modulation ring modulated signals where a higher frequency is modulated by a lower frequency. References http www.tech faq.com frequencies of the telephone tones.html Category Telephony signals ... more details
Demineralized bone matrix DBM is allograft bone that has had the inorganic mineral removed, leaving behind the organic collagen matrix. It was first discovered by Marshall Urist in 1965 that the removal of the bone mineral exposes more biologically active bone morphogenetic proteins . ref Urist, Marshall R. 1965 . Bone formation by autoinduction . Science 12 150 698 893 899. doi 10.1126 science.150.3698.893. PMID 5319761. ref These growth factors modulate the differentiation of progenitor cells into osteoprogenitor cells, which are responsible for bone and cartilage formation. As a result of the demineralization process, DBM is more biologically active than undemineralized bone grafts conversely the mechanical properties are significantly diminished. Current clinical options The success of a bone graft is determined by its ability to recruit host cells to the site of the graft and modulate their conversion into bone forming cells such as osteoblasts , to repair the defect. This will depend on the osteoconductive , osteoinductive and osteogenic capabilities of the graft. Currently, autograft bone harvested from the iliac crest is considered the gold standard due to its superior osteogenic properties. However, associated donor site morbidity , an increased surgery and recovery time, and a limited supply of donor bone are limiting its use ref Graham, S.M., et al., Biological therapy of bone defects the immunology of bone allo transplantation. Expert Opinion on Biological Therapy, 2010. 10 6 p. 885 901. ref . Allograft bone is logical alternative to autograft. However, it must be rigorously processed and terminally sterilized prior to implantation to remove the risk of disease transmission or an immunological response. This processing removes the osteogenic and osteoinductive .... DBM has superior biological properties to undemineralised allograft bone ref Glowacki, J., S. Zhou ... of the graft. Currently, there are a range of DBM products approved by the Food and Drug Administration ... more details
Chembox Watchedfields changed verifiedrevid 458774030 ImageFile Dibenzoylmethane.svg ImageSize ImageAlt IUPACName 1,3 diphenylpropane 1,3 dione OtherNames 2 Benzoylacetophenone Section1 Chembox Identifiers CASNo Ref cascite correct CAS CASNo 120 46 7 PubChem 8433 SMILES C1 CC C C C1 C O CC O C2 CC CC C2 Section2 Chembox Properties Formula C sub 15 sub H sub 12 sub O sub 2 sub MolarMass 224.25 g mol Appearance Density MeltingPt 77 78 C ref name Spectro http dx.doi.org 10.1016 j.saa.2009.12.040 , Jan Zawadiak, Marek Mrzyczek Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 75 2010 pp. 925 929 ref BoilingPt Solubility Section3 Chembox Hazards MainHazards FlashPt Autoignition 1,3 diphenylpropane 1,3 dione dibenzoylmethane, DBM is an aromatic diketone 1,3 diketone , acac acetylacetone acac derivative, where both methyl groups have been substituted by phenyl groups. It is white solid melting 77 78 C. Similarly to acac, DBM exist as two tautomeric forms, however keto enol equilibrium of DBM is strongly shifted to the enol form. It is result of formation of intra molecular hydrogen bond, which is conjugated with phenyl rings. ref name Spectro The resonance assisted hydrogen bond is responsible for high photostability of such compounds, and therefore, some derivates of DBM e.g. Avobenzone have found application as sunscreen s. References references Category Ketones Category Chelating agents Category Ligands fa pl Dibenzoilometan ... more details
to received power of 115 dBm or 0.40 microvolts in 50 ohms on HF. A strong signal with signal strength of S8 corresponds to received power of 79 dBm or 25 microvolts in 50 ohms on HF. Some signal ... HF Signal Generator emf V 50 dBm dB above 1uV S9 10dB 160.0 63 44 S9 50.2 73 34 S8 25.1 79 28 S7 ... S9 for an input of 73 dBm but do not provide the correct 6 dB per S unit correspondence. Often the correlation ... more details
the power is expressed in dBm the larger the absolute value of the negative number, the better the receive sensitivity. For example, a receiver sensitivity of 98 dBm is better than a receive sensitivity of 95 dBm by 3 dB, or a factor of two. In other words, at a specified data rate, a receiver with a 98 dBm sensitivity can hear signals that are half the power of those heard by a receiver with a 95 dBm receiver sensitivity. References FS1037C MS188 External links http www.sengpielaudio.com ... more details
In radio communication systems, Equivalent isotropically radiated power EIRP or, alternatively, Effective isotropically radiated power ref IEEE Std. 100 The Authoritative Dictionary of IEEE Standards Terms, 7th Edition , The Institute of Electrical and Electronics Engineers, New York, 2000, ISBN 0 7381 2601 2, page 391 ref is the amount of power that a theoretical isotropic antenna which evenly distributes power in all directions would emit to produce the peak power density observed in the direction of maximum antenna gain . EIRP can take into account the losses in transmission line and connectors and includes the gain of the antenna. The EIRP is often stated in terms of decibel s over a reference power emitted by an isotropic radiator with an equivalent signal strength. The EIRP allows comparisons between different emitters regardless of type, size or form. From the EIRP, and with knowledge of a real antenna s gain, it is possible to calculate real power and field strength values. math EIRP P T L c G a math where math EIRP math and math P T math power of transmitter are in dBm , cable losses math L c math is in Decibel dB , and antenna gain math G a math is expressed in dBi , relative to a theoretical isotropic reference antenna. This example uses dBm, although it is also common to see dBW . Decibel s are a convenient way to express the ratio between two quantities. dBm uses a reference of 1 mW and dBW uses a reference of 1 W. math text dBm 10 log left power out 1 , mathrm mW right math and math text dBW 10 log left power out 1 , mathrm W right math A transmitter with a 50W output can be expressed as a 17 dBW output or 47 dBm. math 16.9897 , mathrm dBW 10 log left 50 , mathrm W 1 , mathrm W right math The EIRP is used to estimate the service area of the transmitter, and to coordinate transmitters on the same frequency so that their coverage areas do not overlap. In built up areas, regulations may restrict the EIRP of a transmitter to prevent exposure of p ... more details
ndbm standing for New Database Manager is a Berkeley produced version from 1986 of the AT&T dbm database. ndbm stores arbitrary data by use of a single key in fixed size buckets. Problems The sum of the sizes of a key content pair must not exceed the internal block size normally between 512 and 4096 bytes . Moreover all key content pairs that hash together must fit on a single block. Discussion When storing an entry, dbm store stores the data in the block that corresponds to the hash of the key. If two or more keys hashes to the same value, all data for those keys must be stored in the same data block. dbm store is supposed to return an error in the event that a disk block fills up, but there are situations where it doesn t, and you could just end up quietly delete another entry. Since you do not know which keys hash together, you may not depend on them hashing to different buckets. If you are unlucky, all your keys could hash to the same hash value and therefore all your data and some unknown internal metadata must fit in one bucket, which is one block normally 512 4096 bytes . This means that the entire database is only guaranteed to be fully stored and retrievable if the entire dataset including some internal metadata fits in one disk block. If you store more data than that, some data may in some situations just quietly disappear. Obviously, because of this, if you are interested in being able to retrieve stored data, ndbm should not be used, and almost any other storage format is better than ndbm. The problem is very seldom mentioned in the documentation. One of the few places is a note in the Solaris ndbm 3C man page. ref cite web author Oracle Solaris title Solaris ndbm 3C man page, under notes url http download.oracle.com docs cd E19082 01 819 2243 ndbm 3c index.html Notes ref Still, for historical reasons, ndbm is delivered with several operating systems and used by several programs and systems out there. References reflist refbegin refend Category Database management ... more details
Donkada Bhuvan Mohan Patnaik October 31, 1925 February 11, 2009 , also known as D. B. M. Patnaik or simply DBM , was an Indian lawyer, politician and communist leader. He was from Bhagimpeta in Srikakulam district . ref name Hindu obit cite news url http www.hindu.com 2009 02 12 stories 2009021253920600.htm title UCCRI ML leader DBM passes away date February 12, 2009 publisher The Hindu accessdate 28 December 2009 ref Patnaik practiced law at the Gunupur district court where he met Nagbhushan Patnaik both of them defended peasants in court cases. In 1967, the two of them became active in the naxalite movement that lead to the formation of the Communist Party of India Marxist Leninist . ref cite journal last Banerjee first Sumanta title Nagbhushan Patnaik and His Political Legacy journal Economic and Political Weekly volume 33 issue 44 pages 2775&ndash 2776 jstor 4407316 ref Patnaik started his political career with the Communist Party of India and subsequently joined the CPI M . Along with Nagbhushan Patnaik, he joined the revolutionary communists in the Srikakulam Girijan Naxalbary movement . He was an active leader of the movement and subsequently joined the CPI ML which was formed after the various naxalite movements. He was active in various trade union movements and was also instrumental in the struggles of the people belonging to the lower economic strata of coastal Andhra Pradesh and Orissa. ref name Hindu obit Patnaik died on February 9, 2009 at the age of 84, after developing complications from surgery. ref name Hindu obit References reflist Persondata Metadata see Wikipedia Persondata . NAME Patnaik, Donkada ALTERNATIVE NAMES DBM SHORT DESCRIPTION Indian politician DATE OF BIRTH October 31, 1925 PLACE OF BIRTH DATE OF DEATH February 11, 2009 PLACE OF DEATH DEFAULTSORT Patnaik, Donkada Category Indian communists Category Indian lawyers Category 1925 births Category 2009 deaths CPIndia politician stub ... more details
The log distance path loss model is a radio propagation model that predicts the path loss a Wiktionary signal signal encounters inside a building or densely populated areas over distance. Applicable to Under conditions The model is applicable to indoor propagation modeling. Mathematical formulation The model Log distance path loss model is formally expressed as math PL P Tx dBm P Rx dBm PL 0 10 gamma log 10 frac d d 0 X g, math where math PL math is the total path loss measured in Decibel dB math P Tx dBm 10 log 10 frac P Tx 1mW math is the transmitted power in dBm , where math P Tx math is the transmitted power in watt . math P Rx dBm 10 log 10 frac P Rx 1mW math is the received power in dBm, where math P Rx math is the received power in watt. math PL 0 math is the path loss at the reference distance d sub 0 sub . Unit Decibel dB math d math is the length of the path. math d 0 math is the reference distance, usually 1 km or 1 mile . math gamma math is the path loss exponent. math X g math is a normal random variable normal or Gaussian random variable with zero mean , reflecting the attenuation in decibel caused by flat fading Citation needed date October 2011 . In case of no fading, this variable is 0. In case of only shadow fading or slow fading , this random variable may have Gaussian distribution with math sigma math standard deviation in Decibel dB , resulting in log normal distribution of the received power in Watt. In case of only fast fading caused by multipath propagation, the corresponding gain in Watts math F g 10 frac X g 10 math may be modelled as a random variable with Rayleigh distribution or Ricean distribution ref cite book title Handbook of Propagation Effects for Vehicular and Personal Mobile Satellite Systems author Julius Goldhirsh coauthors Wolfhard J. Vogel url http www.utexas.edu research mopro papercopy chapter11.pdf chapter 11.4 ref . Corresponding non logarithmic model This corresponds to the following non logarithmic gain model math frac ... more details
Flat weighting In a noise measuring set, a noise weighting based on an amplitude frequency characteristic that is flat over a frequency range that must be stated. Note 1 Flat noise power is expressed in dBrn f sub 1 sub f sub 2 sub or in dBm f sub 1 sub f sub 2 sub . Note 2 3 kHz flat weighting and 15 kHz flat weighting are based on amplitude frequency characteristics that are flat between 30 Hz and the frequency indicated. References FS1037C MS188 Category Noise ... more details
lowercase dBm0 is an abbreviation for the power in dBm measured at a zero transmission level point . dBm0 is a concept used amongst other areas in audio telephony processing since it allows a smooth integration of analog and digital chains. Notably, for A law and law codecs the standards define a sequence which has a 0 dBm0 output. Note 1 A consequence for the A law and law codecs of the 0 dBm0 definition is that they have a respective 3.14 dBm0 and 3.17 dBm0 maximum signal level ratio between the maximum obtainable sine wave amplitude and the specified reference 0 dBm0 sine wave amplitude . Note 2 0 dBm0 is often replaced by or used instead of digital milliwatt or zero transmission level point . Sources http portal.etsi.org stq ES202020 TIA 912.pdf ETSI G.711 Category Radio frequency propagation telecomm stub ... more details
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