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The '''sensitivity''' of an electronic device, such as a [[communications system]] receiver, or detection device, such as a [[PIN diode]], is the minimum [[magnitude (mathematics)|magnitude]] of input [[Signalling (telecommunication)|signal]] required to produce a specified output signal having a specified [[signal-to-noise ratio]], or other specified criteria. | |||
''Sensitivity'' is sometimes improperly used as a synonym for ''[[responsivity]]''.{{CN|date=March 2013}} | |||
The sensitivity of a [[microphone]] is usually expressed as the [[sound]] [[field strength]] in [[decibel]]s (dB) relative to 1 [[volt|V]]/[[Pascal (unit)|Pa]] (Pa = [[newton (unit)|N]]/[[meter|m]]<sup>2</sup>) or as the transfer factor in millivolts per [[pascal (unit)|pascal]] (mV/Pa) into an [[Open-circuit voltage|open circuit]] or into a 1 kilohm [[Load impedance|load]].{{CN|date=March 2013}} | |||
The sensitivity of a [[loudspeaker]] is usually expressed as dB / 2.83 V<sub>RMS</sub> at 1 metre. This is not the same as the [[electrical efficiency]]; see [[Loudspeaker#Efficiency_vs._sensitivity|Efficiency vs sensitivity]].{{CN|date=March 2013}} | |||
The sensitivity of a [[hydrophone]] is usually expressed as dB re 1 V/µPa.{{CN|date=March 2013}} | |||
Sensitivity in a receiver is normally defined as the minimum input signal <math>S_i</math> required to produce a specified signal-to-noise S/N ratio at the output port of the receiver and is defined as the mean noise power at the input port of the receiver times the minimum required signal-to-noise ratio at the output of the receiver: | |||
:<math>S_i = k(T_a+T_{rx})B{\cdot}\frac{S_o}{N_o}</math> | |||
where | |||
:''<math>S_i</math>'' = sensitivity [W] | |||
:''k'' = [[Boltzmann's constant]] | |||
:<math>T_a</math> = [[equivalent noise temperature]] in [K] of the source (e.g. antenna) at the input of the receiver | |||
:<math>T_{rx}</math> = equivalent noise temperature in [K] of the receiver referred to the input of the receiver | |||
:''B'' = bandwidth [Hz] | |||
:''<math>\frac{S_o}{N_o}</math>'' = Required SNR at output [-] | |||
Because receiver sensitivity indicates how faint an input signal can be to be successfully received by the receiver, the lower power level, the better. Lower power for a given S/N ratio means better sensitivity since the receiver's contribution is smaller. When 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.{{Citation needed|date=March 2013}} | |||
== References == | |||
{{FS1037C MS188}} | |||
==External links== | |||
*[http://www.sengpielaudio.com/calculator-transferfactor.htm Microphone sensitivity conversion from dB at 1 V/Pa to transfer factor in mV/Pa] | |||
[[Category:Electronics terminology]] | |||
Revision as of 04:25, 10 January 2014
The sensitivity of an electronic device, such as a communications system receiver, or detection device, such as a PIN diode, is the minimum magnitude of input signal required to produce a specified output signal having a specified signal-to-noise ratio, or other specified criteria.
Sensitivity is sometimes improperly used as a synonym for responsivity.Template:CN
The sensitivity of a microphone is usually expressed as the sound field strength in decibels (dB) relative to 1 V/Pa (Pa = N/m2) or as the transfer factor in millivolts per pascal (mV/Pa) into an open circuit or into a 1 kilohm load.Template:CN
The sensitivity of a loudspeaker is usually expressed as dB / 2.83 VRMS at 1 metre. This is not the same as the electrical efficiency; see Efficiency vs sensitivity.Template:CN
The sensitivity of a hydrophone is usually expressed as dB re 1 V/µPa.Template:CN
Sensitivity in a receiver is normally defined as the minimum input signal required to produce a specified signal-to-noise S/N ratio at the output port of the receiver and is defined as the mean noise power at the input port of the receiver times the minimum required signal-to-noise ratio at the output of the receiver:
where
- = sensitivity [W]
- k = Boltzmann's constant
- = equivalent noise temperature in [K] of the source (e.g. antenna) at the input of the receiver
- = equivalent noise temperature in [K] of the receiver referred to the input of the receiver
- B = bandwidth [Hz]
- = Required SNR at output [-]
Because receiver sensitivity indicates how faint an input signal can be to be successfully received by the receiver, the lower power level, the better. Lower power for a given S/N ratio means better sensitivity since the receiver's contribution is smaller. When 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.Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.