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35-470: (Redirected from Line Out ) [REDACTED] Look up line out in Wiktionary, the free dictionary. Line out can refer to: Line out (signal) , an analog electrical signal for connection between audio devices Line-out (rugby union) , a means of restarting play in rugby union Lineout (baseball) , a type of play in baseball when a player catches

70-422: A 3.5 mm (0.14 inch, but commonly called "eighth inch") 3-conductor TRS minijack connector providing ground, left channel, and right channel, or stereo RCA jacks . Professional equipment commonly uses balanced connections on 6.35 mm (1/4 inch) TRS phone jacks or XLR connectors . Professional equipment may also use unbalanced connections with (1/4 inch) TS phone jacks. A line level describes

105-471: A 600 Ω load. The corresponding voltage level is 0 dBu , without the 600 Ω restriction. Conversely, for RF situations with a 50 Ω load, 0 dBm corresponds to approximately 0.224 volts, since 0.224 V dissipates 1 mW in a 50 Ω load. In general the relationship between the power level P in dBm and the RMS voltage V in volts across a load of resistance R (typically used to terminate

140-488: A few hundred ohms; the lowest of these will have results similar to a speaker, while the highest may work acceptably if the line out impedance is low enough and the headphones are sensitive enough. Conversely, a headphone output generally has a source impedance of only a few ohms (to provide a bridging connection with 32 ohm headphones) and will easily drive a line input. For similar reasons, "wye"-cables (or "Y-splitters") should not be used to combine two line out signals into

175-454: A high impedance compared to that of line outputs, they should not be confused with so-called "Hi-Z" inputs (Z being the symbol for impedance ) which have an impedance of 47 kΩ to over 1 MΩ . These "Hi-Z" or "instrument" inputs generally have higher gain than a line input. They are designed to be used with, for example, electric guitar pickups and " direct injection " boxes. Some of these sources can provide only minimal voltage and current and

210-450: A line drive Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Line out . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Line_out&oldid=1056109123 " Category : Disambiguation pages Hidden categories: Short description

245-452: A line's nominal signal level as a ratio, expressed in decibels , against a standard reference voltage. The nominal level and the reference voltage against which it is expressed depend on the line level being used. While the nominal levels themselves vary, only two reference voltages are common: decibel volts (dBV) for consumer applications, and decibels unloaded (dBu) for professional applications. The decibel volt reference voltage

280-404: A power of 1 milliwatt. A 10 dB increase in level is equivalent to a ten-fold increase in power. Therefore, a 20 dB increase in level is equivalent to a 100-fold increase in power. A 3 dB increase in level is approximately equivalent to doubling the power, which means that a level of 3 dBm corresponds roughly to a power of 2 mW. Similarly, for each 3 dB decrease in level,

315-416: A preamp; typically, a home stereo integrated amplifier or receiver will have a special phono input . This input passes the signal through a phono preamp, which applies RIAA equalization to the signal as well as boosting it to line level. DBm dBm or dB mW (decibel-milliwatts) is a unit of power level expressed using a logarithmic decibel (dB) scale respective to one milliwatt (mW). It

350-419: A single line in. Each line output would be driving the other line output as well as the intended input, again resulting in a much heavier load than designed for. This will result in signal loss and possibly even damage. An active mixer, using for example op-amps , should be used instead. A large resistor in series with each output can be used to safely mix them together, but must be appropriately designed for

385-431: A transmission line with impedance Z ) is: V = R 10 P / 10 1000 . {\displaystyle {\begin{aligned}V&={\sqrt {R{\frac {10^{P/10}}{1000}}}}\,.\end{aligned}}} Expression in dBm is typically used for optical and electrical power measurements, not for other types of power (such as thermal). A listing by power levels in watts

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420-417: Is +4 dBu (by convention, decibel values are written with an explicit sign symbol). For consumer equipment it is −10 dBV , which is used to reduce manufacturing costs. Expressed in absolute terms, a signal at −10 dBV is equivalent to a sine wave signal with a peak amplitude (V PK ) of approximately 0.447 volts , or any general signal at 0.316 volts root mean square (V RMS ). A signal at +4 dBu

455-565: Is 1 V RMS = 0 dBV . The decibel unloaded reference voltage, 0 dBu , is the AC voltage required to produce 1 mW of power across a 600 Ω impedance (approximately 0.7746 V RMS ). This awkward unit is a holdover from the early telephone standards, which used 600 Ω sources and loads, and measured dissipated power in decibel-milliwatts ( dBm ). Modern audio equipment does not use 600 Ω matched loads, hence dBm unloaded ( dBu ). The most common nominal level for professional equipment

490-536: Is EU only, the latter is US only. Also, maximal power allowed by the FCC for American amateur radio licensees to fly radio-controlled aircraft or operate RC models of any other type on the amateur radio bands in the US. Maximal output from a UMTS/3G mobile phone (power class 2 mobiles) 1,880–1,900 MHz DECT (250 mW per 1,728 kHz channel). EIRP for wireless LAN IEEE 802.11a (20 MHz-wide channels) in either

525-438: Is a table summarizing useful cases: Typical maximum output RF power from a ham radio HF transceiver without power amplifier Maximal output from a GSM850/900 mobile phone DCS or GSM 1,800/1,900 MHz mobile phone. EIRP IEEE 802.11a (20 MHz-wide channels) in either 5 GHz subband 2 (5,470–5,725 MHz) provided that transmitters are also IEEE 802.11h-compliant, or U-NII -3 (5,725–5,825 MHz). The former

560-405: Is advertised as at least 20 Hz to 20 kHz, which corresponds to the range of human hearing . Line outputs are intended to drive a load impedance of 10,000 ohms; with only a few volts, this requires only minimal current. Connecting a low-impedance load such as a loudspeaker (usually 4 to 8 Ω ) to a line out will essentially short circuit the output circuit. Such loads are around 1/1000

595-468: Is an alternating current signal without a DC offset, meaning that its voltage varies with respect to signal ground from the peak amplitude (for example +1.5 V ) to the equivalent negative voltage ( −1.5 V ). As cables between line output and line input are generally extremely short compared to the audio signal wavelength in the cable, transmission line effects can be disregarded and impedance matching need not be used. Instead, line level circuits use

630-399: Is commonly used by radio, microwave and fiber-optical communication technicians & engineers to measure the power of system transmissions on a log scale , which can express both very large and very small values in a short form. dBW is a similar unit measured relative to one watt (1,000 mW), rather than a milliwatt. The decibel ( dB ) is a dimensionless unit , used for quantifying

665-533: Is different from Wikidata All article disambiguation pages All disambiguation pages Line out (signal) Generally, line level signals sit in the middle of the hierarchy of signal levels in audio engineering. There are weaker signals such as those from microphones (Mic Level/Microphone Level) and instrument pickups (Instrument Level), and stronger signals, such as those used to drive headphones and loudspeakers (Speaker Level). The "strength" of these various signals does not necessarily refer to

700-429: Is equivalent to a sine wave signal with a peak amplitude of approximately 1.736 volts , or any general signal at approximately 1.228 V RMS . Peak-to-peak (sometimes abbreviated as p-p ) amplitude (V PP ) refers to the total voltage swing of a signal, which is double the peak amplitude of the signal. For instance, a signal with a peak amplitude of ±0.5 V has a p-p amplitude of 1.0 V . The line level signal

735-426: Is performed by a device known as a preamplifier or "preamp", which boosts the signal to line level. After manipulation at line level, signals are then typically sent to a power amplifier , where they are amplified to levels that can drive headphones or loudspeakers . These convert the signals back into sounds that can be heard through the air. Most phonograph cartridges also have a low output level and require

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770-408: The impedance bridging principle, in which a low impedance output drives a high impedance input. A typical line out connection has an output impedance from 100 to 600 Ω, with lower values being more common in newer equipment. Line inputs present a much higher impedance, typically 10 kΩ or more. The two impedances form a voltage divider with a shunt element that is large relative to the size of

805-485: The 'm' suffix, is permitted for relative quantities, but not accepted for use directly alongside SI units. Ten decibel-milliwatts may be written 10 dB (1 mW) in SI. In audio and telephony, dBm is typically referenced relative to the 600-ohm impedance commonly used in telephone voice networks, while in radio-frequency work dBm is typically referenced relative to a 50-ohm impedance. A power level of 0 dBm corresponds to

840-400: The 5 GHz subband 1 (5,180–5,320 MHz) or U-NII -2 and -W ranges (5,250–5,350 MHz & 5,470–5,725 MHz, respectively). The former is EU only, the latter is US only. Bluetooth Class 1 radio. Maximal output power from unlicensed AM transmitter per US FCC rules 15.219 The signal intensity (power per unit area) can be converted to received signal power by multiplying by

875-403: The high impedance input is designed to not load them excessively. Acoustic sounds (such as voices or musical instruments ) are often recorded with transducers ( microphones and pickups ) that produce weak electrical signals. These signals must be amplified to line level, where they are more easily manipulated by other devices such as mixing consoles and tape recorders. Such amplification

910-436: The impedance a line out is designed to drive, so the line out is usually not designed to source the current that would be drawn by a 4 to 8 ohm load at normal line out signal voltages. The result will be very weak sound from the speaker and possibly a damaged line out circuit. Headphone outputs and line outputs are sometimes confused. Different make and model headphones have widely varying impedances, from as little as 20 Ω to

945-454: The information, making the current irrelevant. [REDACTED]    [REDACTED]    [REDACTED]    [REDACTED]    Line-out symbol. PC Guide color   lime green. Line outputs usually present a source impedance of from 100 to 600 ohms . The voltage can reach 2 volts peak-to-peak with levels referenced to −10 dBV (300 mV) at 10 kΩ . The frequency response of most modern equipment

980-426: The load impedance and cable length. [REDACTED]    [REDACTED]    [REDACTED]    [REDACTED]    Line-in symbol. PC Guide color   light blue. It is intended by designers that the line out of one device be connected to the line input of another. Line inputs are designed to accept voltage levels in the range provided by line outputs. Impedances, on

1015-438: The other hand, are deliberately not matched from output to input. The impedance of a line input is typically around 10 kΩ . When driven by a line output's usual low impedance of 100 to 600 ohms, this forms a "bridging" connection in which most of the voltage generated by the source (the output) is dropped across the load (the input), and minimal current flows due to the load's relatively high impedance. Although line inputs have

1050-430: The output voltage of the source device; it also depends on its output impedance and output power capability. Consumer electronic devices concerned with audio (for example sound cards ) often have a connector labeled line in and/or line out . Line out provides an audio signal output and line in receives a signal input. The line in/out connections on consumer-oriented audio equipment are typically unbalanced , with

1085-724: The power is reduced by about one half, making −3 dBm correspond to a power of about 0.5 mW. To express an arbitrary power P in mW as x in dBm, the following expression may be used: x = 10 log 10 ⁡ P 1   mW {\displaystyle {\begin{aligned}x&=10\log _{10}{\frac {P}{1~{\text{mW}}}}\end{aligned}}} Conversely, to express an arbitrary power level x in dBm, as P in mW: P = 1   mW ⋅ 10 x 10 {\displaystyle {\begin{aligned}P&=1~{\text{mW}}\cdot 10^{\frac {x}{10}}\end{aligned}}} Below

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1120-489: The ratio between two values, such as signal-to-noise ratio . The dBm is also dimensionless, but since it compares to a fixed reference value, the dBm rating is an absolute one. The dBm is not a part of the International System of Units (SI) and therefore is discouraged from use in documents or systems that adhere to SI units. (The corresponding SI unit is the watt.) However, the unit decibel (dB), without

1155-455: The series element, which ensures that little of the signal is shunted to ground and that current requirements are minimized. Most of the voltage asserted by the output appears across the input impedance and almost none of the voltage is dropped across the output. The line input acts similarly to a high impedance voltmeter or oscilloscope input, measuring the voltage asserted by the output while drawing minimal current (and hence minimal power) from

1190-433: The source. The high impedance of the line in circuit does not load down the output of the source device. These are voltage signals (as opposed to current signals) and it is the signal information (voltage) that is desired, not power to drive a transducer , such as a speaker or antenna. The actual information that is exchanged between the devices is the variance in voltage; it is this alternating voltage signal that conveys

1225-485: The square of the wavelength and dividing by 4 π (see Free-space path loss ). In United States Department of Defense practice, unweighted measurement is normally understood, applicable to a certain bandwidth , which must be stated or implied. In European practice, psophometric weighting may be, as indicated by context, equivalent to dBm0p , which is preferred. In audio, 0 dBm often corresponds to approximately 0.775 volts, since 0.775 V dissipates 1 mW in

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