Decibel (decibel,db) is a ratio function that operates on dimensionless parameters:
DB=˙10LOG10 (x), where x is unitless D B =˙10 l o G Ten (x), where x is unitless dB \dot = Ten log_{10} (x), \quad \text{ Where $x $ is unitless}
For example, the amplifier gain is a dimensionless value, which is the ratio of output power to input power:
Poutpin=gtherefore Gain i
DBMPower Unit and P (Watt) conversion formula:DBM = 30 + 10lgp (P: Tile)First, DB is a pure counting unit: DB = 10 logX. The significance of DB is actually a simple one, that isThe number of large (followed by a long string of 0) or small (followed by a long string of 0) is briefly expressed. For example:X = 1000000000
magnification is three, it is easy to calculate and write errors. But expressed in db form, respectively, 10db,20db,30db, the total magnification of 10+20+30=60db, convenient a lot.It is because of the benefits that science and other fields such as electronics, such as seismic grade, sound size, and so on, are used in decibels or similar to the exponential representation of decibels.DBMW/DBM/
, intermodulation interference, out-of-band interference, etc.) as well as the relative magnitude of the coupling, spurious, etc. In principle, db substitution can be used where DBC is used.4, DBm dbm is a value that represents absolute power (or a ratio that is based on 1mW Power) and is calculated as: 10log (Power value/1MW). [Example] if the power P is 1mw, co
to each other:1. DBM = 10 x log [Power MW]2. Mw = 10 [gain DBM/10 dBm] in a wireless system, an antenna is used to convert current waves into electromagnetic waves. During the conversion process, it can also "zoom in" The transmitted and received signals ", the measurement of this type of energy amplification is "gai
1. DBM
DBM is the absolute value of power. The formula is: 10lgp (power value/1 MW ).
[Example 1] If the transmit power P is 1 MW, it is converted to dBm and then 0dbm.
[Example 2] for 40 W power, the converted value in dBm unit should be:
10lg (40 W/1 MW) = 10lg (40000) = 10lg4 + 10lg10 + 10lg1000 = 46dbm.
2. DBI and
than B's power, the following formula is used: 10lg (a power/B power)[Example 6] If the power of a is twice the power of B, then 10lg (the power of a/B) = 10lg2 = 3 dB. That is to say, the power of a is 3 dB higher than that of B.[Example 7] 8 inch M transmission loss of the 100/GSM 900 feeder is about dB.[Example 8] If the power of a is 46dbm and that of B is 4
DB, which represents a relative value. When calculating A's power compared to b large or small number of db, can be calculated as the formula 10LG A/b. For example: A power is one-fold larger than B power, then 10lg A/b = 2 lg = 3dB, that is, the power of a is greater than the power of B 3dB; If the power of a 46dbm,b is 40dBm, it can be said that a is greater than B 6dB; if the a antenna is 12dBm, b antenn
/10DBM]In wireless systems, antennas are used to convert current waves into electromagnetic waves, and in the process of transmitting and receiving signals can be "putThe metric of this energy amplification becomes "gain (Gain)". The unit of measure for antenna gain is "dBi". Because the power in the wireless systemThe magnetic wave energy is generated by the transmitting energy of the transmitting device and the amplification and superposition of the antenna, so the measurement of emission ener
The OLE DB command executes an OLE DB command on the data rows in the data flow. It updates each row in the data table and stores the data that will be updated in the table beforehand. Or for a stored procedure with input parameters, these parameters can be stored in a data table without having to enter parameters each time.Sample Data Preparation:CREATE TABLE INT INT ) CREATETABLEINTint ) INSERT VA
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