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Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in unit of hertz.
The decibel is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 101/10 or root-power ratio of 101/20.
dBm or dBmW (decibel-milliwatts) is a unit of power level expressed using a logarithmic decibel (dB) scale respective to one milliwatt (mW). It 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.
In digital telephony, the digital milliwatt is a standard test signal that serves as a reference for analog signal levels in the telecommunications network. When decoding the digital milliwatt, a PCM decoder produces a sinusoidal signal with a frequency of 1 kHz with one milliwatt in power.
Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 indicates more signal than noise.
The decibel watt is a unit for the measurement of the strength of a signal expressed in decibels 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.
Line level is the specified strength of an audio signal used to transmit analog sound between audio components such as CD and DVD players, television sets, audio amplifiers, and mixing consoles.
A volume unit (VU) meter or standard volume indicator (SVI) is a device displaying a representation of the signal level in audio equipment.
In telecommunications, received signal strength indicator or received signal strength indication (RSSI) is a measurement of the power present in a received radio signal.
An RF switch or microwave switch is a device to route high frequency signals through transmission paths. RF and microwave switches are used extensively in microwave test systems for signal routing between instruments and devices under test (DUT). Incorporating a switch into a switch matrix system enables you to route signals from multiple instruments to single or multiple DUTs. This allows multiple tests to be performed with the same setup, eliminating the need for frequent connects and disconnects. The entire testing process can be automated, increasing the throughput in high-volume production environments.
Decibels relative to full scale is a unit of measurement for amplitude levels in digital systems, such as pulse-code modulation (PCM), which have a defined maximum peak level. The unit is similar to the units dBov and decibels relative to overload (dBO).
A peak programme meter (PPM) is an instrument used in professional audio that indicates the level of an audio signal.
In telephony, a special information tone (SIT) is an in-band international standard call progress tone consisting of three rising tones indicating a call has failed. It usually precedes a recorded announcement describing the problem.
In electronics, crosstalk is a phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, inductive, or conductive coupling from one circuit or channel to another.
BORSCHT is an acronym for the set of functions performed by a subscriber line interface circuit (SLIC) in the line card of a telecommunication system providing plain old telephone service. The letters represent the following functions: battery feed (B), overvoltage protection (O), ringing (R), signaling (S), coding (C), hybrid (H), and test (T).
dBm0 is an abbreviation for the power in dBm measured at a zero transmission level point (ZLP).
Nominal level is the operating level at which an electronic signal processing device is designed to operate. The electronic circuits that make up such equipment are limited in the maximum signal they can handle and the low-level internally generated electronic noise they add to the signal. The difference between the internal noise and the maximum level is the device's dynamic range. The nominal level is the level that these devices were designed to operate at, for best dynamic range and adequate headroom. When a signal is chained with improper gain staging through many devices, clipping may occur or the system may operate with reduced dynamic range.
A Milliwatt test is a test method or test facility used in telecommunications to measure line quality and transmission loss between stations or points in an analog telephone system.
The watt is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named in honor of James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution.
WSPR is an acronym for Weak Signal Propagation Reporter. It is a protocol, implemented in a computer program, used for weak-signal radio communication between amateur radio operators. The protocol was designed, and a program written initially, by Joe Taylor, K1JT. The software code is now open source and is developed by a small team. The program is designed for sending and receiving low-power transmissions to test propagation paths on the MF and HF bands.
References
- 1 2 Whitham D. Reeve (1992) Subscriber Loop Signaling and Transmission Handbook—Analog, IEEE Press, p.229
- 1 2 "Transmission level point (TLP)". Glossary of Telecommunication Terms. Telecommunication Industry Association (TIA). Retrieved 2023-05-19.
- ↑ Reeve, Whitham D. (1996). "Application Note No. 8" (PDF). reeve.com. Archived (PDF) from the original on 2023-02-01. Retrieved 2023-06-26.