Parts Express - Tech Terms Glossary

Tech Terms Glossary

A / B / C / D / E / F / G / H / I / J / K / L / M / N / O / P / Q / R / S / T / U / V / W / X / Y / Z

N/D (Neutral Density) Filter: A filter that attenuates light equally over the whole visible spectrum.

900-MHZ Reception System: Advanced cordless technology that transmits at a higher frequency band than that used by more common cordless equipment, for increased transmitter-to-reciever range and greater signal clarity.

Noise: Random spurts of electrical energy or interference.

Nickel Cadmium (Ni-Cad): Combinations of these two elements can be used to hold a rechargeable amount of electricity. Most commonly used in rechargeable batteries and cells.

Nickel-Metal Hydride (NiMH): Modern, high-capacity, rechargeable cell or battery. Often used in cellular phones and other devices where smaller size and weight are desirable without a loss in performance.

no: The reference efficiency of a loudspeaker with a half-space acoustical load.

NTSC (National Television Standards Committee): National Television Systems Committee that worked with the FCC in formulating the standards for the United States color television system. Also a video format used in the US that uses 525 scanning lines in accordance with American television regulations.

1-Bit D/A (Digital-To-Analog) Converter: Circuitry that translates the signal from a CD into an analog waveform using either a 1-bit pulse-density modulation (PDM) or 1-bit pulse width modulation (PWM) technique. In the case of PDM, signal information is represented by a series of pulses that have identical amplitude and duration but are either positive or negative. In PWM, the signal pulses all have the same amplitude but varying durations or widths. In both cases, the signal must be filtered before an analog waveform can be recovered.

1-Bit Dual D/A Converter: Since conventional multi-bit converters perform with the combined capabilities of many bits, they are prone to non-linear distortion. One bit converters, as used in most CD changers/players, process the signal by a signal bit at an extremely rapid rate. Since only one bit is operating, distortion is virtually eliminated and the unit is able to deliver sound that is true to the source.

Ohm: Represented by the Greek omega symbol. It is the unit of measurement for resistance and impedance.

Optical Digital Audio Input / Output: On selected components with digital audio, this feature allows a pure digital-to-digital connection between units for audio transfer entirely in the digital domain.

Oversampling: A digital filtering technique used in CD components: Extra data points are added to the audio read from a disc, creating a signal that is some multiple (usually two, four, or eight times) of the CD format's standard sampling frequency This process raises the frequency of any false information, which can then be removed by an analog filter.

PAL (Phase Alternation by Line): A common composite color transmission system used in Europe and elsewhere.

Parallel Push-Pull Circuitry: Amplifier circuitry that uses two output transistors each for the positive and negative halves of the signal cycle. Although it is costly, such circuitry greatly increases amplifier power handling and lengthens product life. It is found in selected audio equipment.

Passive: A non-powered element of a system.

Pe: The maximum electrical power that a speaker driver can handle before it is damaged, usually when the voice coil burns.

Peak-To-Peak: The amplitude difference between the most positive and the most negative excursions of a signal.

Pinhole Lens: Lens used for applications where the camera/lens must be hidden. Front of lens has a small opening to allow the lens to view an entire room through a small hole in a wall.

Piston: The moving portion of a loudspeaker. Includes the cone, dust cap, and surround.

Pitch Control: A control allowing speed changes of the record within a certain range, usually 6%-12%.

Pixel: The smallest unit of picture information in an electronic imaging device, such as a computer monitor, camcorder imager (CCD), or liquid crystal display (LCD). The larger the number of pixels that comprise such a picture, the clearer and more detailed the picture can be.

Polarity: Positive (+) and Negative (-) markings on a battery or other device that indicate the direction of flow of electrical current and voltage. The negative pole will have a surplus of free flowing electrons, where the positive pole will have a deficit of free flowing electrons.

Power: The rate at which electrical energy is applied to or taken from a device. It is expressed in terms of watts, milliwatts or microwatts.

Power Inverter: Converts DC voltage to AC voltage.

Pre-position Lenses: Zoom lenses which utilize a variable-resistor (potentiometer) to indicate zoom/focus position to the lens controller. After initial set-up, this allows the operator to view different pre-set areas quickly without having to re-adjust the zoom and focus each time.

Primary Cell: A cell that cannot be recharged. Must be replaced when discharged.

Q: The losses or relative damping (ratio of stored to dissipated energy or ratio of reactive to resistive energy) of a system.

Q't: The total Q of a loudspeaker's suspension with the load of the rear chamber in a 4th-order bandpass box.

Qec: The Q of a sealed (closed) loudspeaker at Fc considering only its electrical (non-mechanical) resistances.

Qes: The losses or relative damping (ratio of stored to dissipated energy or ratio of reactive to resistive energy) of a vented loudspeaker at Fs considering only its electrical (non-mechanical) resistances.

QL: The Q of a vented speaker cabinet resulting from all of the box losses (acoustic weaknesses).

Qmc: The Q of a sealed loudspeaker cabinet at Fc, considering only its mechanical (non-electrical) resistances.

Qms: The losses or relative damping (ratio of stored to dissipated energy or ratio of reactive to resistive energy) of a vented loudspeaker cabinet at Fs, considering only its mechanical (non-electrical) resistances.

Qtc: The Q of a sealed loudspeaker considering both mechanical and electrical resistances.

Qts: The losses or relative damping (ratio of stored to dissipated energy or ratio of reactive to resistive energy) of a vented loudspeaker considering both mechanical and electrical resistances.