- 行业: Printing & publishing
- Number of terms: 178089
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- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
An electron tube having a light-sensitive receptor that converts an optical image into an electrical television video signal. The tube is used in a television camera to generate a train of electrical pulses representing the light intensities present in an optical image focused on the tube. Each point of this image is interrogated in its proper turn by the tube, and an electrical impulse corresponding to the amount of light at that point of the optical image is generated by the tube. This signal represents the video or picture portion of a television signal. Television camera tubes are designed for broadcast television to pick up live programs, indoors or outdoors, as well as to reproduce motion pictures and other filmed material.
Industry:Science
An electron tube in which a beam of electrons can be focused to a small cross section and varied in position and intensity on a display surface. In common usage, the term cathode-ray tube (CRT) is usually reserved for devices in which the display surface is cathodoluminescent under electron bombardment, and the output information is presented in the form of a pattern of light. The character of this pattern is related to, and controlled by, one or more electrical signals applied to the cathode-ray tube as input information.
Industry:Science
An electronic amplifier circuit used to sense and refresh the value of a bit stored in a memory cell of a dynamic random access memory (DRAM) integrated circuit.
Industry:Science
An electronic circuit capable of producing a waveform that rises abruptly, maintains a relatively flat top for an extremely short interval, and then rapidly falls to zero. A relaxation oscillator, such as a multivibrator, may be adjusted to generate a rectangular waveform having an extremely short duration, and as such it is referred to as a pulse generator. However, there is a class of circuits whose exclusive function is generating short-duration, rectangular waveforms. These circuits are usually specifically identified as pulse generators. An example of such a pulse generator is the triggered blocking oscillator, which is a single relaxation oscillator having transformer-coupled feedback from output to input.
Industry:Science
An electronic circuit for amplification of signals within or somewhat beyond the audio frequency range (generally regarded as 20 to 20,000 Hz). Audio amplifiers may function as voltage amplifiers (sometimes called preamplifiers), power amplifiers, or both. In the last case, they are often called integrated amplifiers.
Industry:Science
An electronic circuit or device producing frequency modulation. This device changes the frequency of an oscillator in accordance with the amplitude of a modulating signal. If the modulation is linear, the frequency change is proportional to the amplitude of the modulating voltage.
Industry:Science
An electronic circuit that consists of elements, which may be transistors, diodes, or resistors, combined in such a manner that they perform a logic operation. Gate circuits are the most basic building blocks of a digital system. These circuits have one or more inputs and one output which is a boolean function of the inputs. The input and output signals can have only two discrete values, low (for example, 0 V) and high (for example, 3.3 V). These values are usually represented as 0 and 1, or “false” and “true,” respectively.
Industry:Science
An electronic circuit that generates a periodic output, often a sinusoid or a square wave. Oscillators have a wide range of applications in electronic circuits: they are used, for example, to produce the so-called clock signals that synchronize the internal operations of all computers; they produce and decode radio signals; they produce the scanning signals for television tubes; they keep time in electronic wristwatches; and they can be used to convert signals from transducers into a readily transmitted form.
Industry:Science
An electronic circuit that generates or modifies an existing waveform to produce a pulse of short time duration with a fast-rising leading edge. This waveform, or trigger, is normally used to initiate a change of state of some relaxation device, such as a multivibrator. The most important characteristic of the waveform generated by a trigger circuit is usually the fast leading edge. The exact shape of the falling portion of the waveform often is of secondary importance, although it is important that the total duration time is not too great. A pulse generator such as a blocking oscillator may also be used and identified as a trigger circuit if it generates sufficiently short pulses.
Industry:Science
An electronic circuit that is designed to amplify the difference between two voltages measured with respect to a common reference, usually designated as ground. By convention, the net difference of two voltages measured with respect to a common reference is called the differential-mode voltage, while the sum of the voltages, usually divided by two to give an average value, is called the common-mode voltage.
Industry:Science
