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The term gain has a different meaning in antenna design; antenna gain is the ratio of radiation intensity from a directional antenna to / (mean radiation intensity from a lossless antenna). Graph of the input () (blue) and output voltage () (red) of an ideal linear amplifier with a voltage gain of 3 with an arbitrary input signal. At any ...
In electronics the amplification factor, or gain, is the ratio of the output to the input of an amplifier, sometimes represented by the symbol A F. In numerical analysis the amplification factor is a number derived using Von Neumann stability analysis to determine stability of a numerical scheme for a partial differential equation .
Friis formula or Friis's formula (sometimes Friis' formula), named after Danish-American electrical engineer Harald T. Friis, is either of two formulas used in telecommunications engineering to calculate the signal-to-noise ratio of a multistage amplifier. One relates to noise factor while the other relates to noise temperature.
For transistors, the current-gain–bandwidth product is known as the f T or transition frequency. [4] [5] It is calculated from the low-frequency (a few kilohertz) current gain under specified test conditions, and the cutoff frequency at which the current gain drops by 3 decibels (70% amplitude); the product of these two values can be thought of as the frequency at which the current gain ...
Gain compression is the difference between the ideal linear power transfer curve and the real circuit's power transfer curve. An important gain compression parameter is the OP1dB, which is the power input that results in a 1 dB compression of the output power (OP), corresponding to a gain ratio of 10-1 ⁄ 10 = 79.4%.
with R 1 = R S || r π and R 2 = R D || r O. This expression can be rewritten in the form used by the asymptotic gain model, which expresses the overall gain of a feedback amplifier in terms of several independent factors that are often more easily derived separately than the overall gain itself, and that often provide insight into the circuit ...
In most amplifiers a reduction in gain takes place before hard clipping occurs; the result is a compression effect, which (if the amplifier is an audio amplifier) sounds much less unpleasant to the ear. For these amplifiers, the 1 dB compression point is defined as the input power (or output power) where the gain is 1 dB less than the small ...
The loop gain is calculated by imagining the feedback loop is broken at some point, and calculating the net gain if a signal is applied. In the diagram shown, the loop gain is the product of the gains of the amplifier and the feedback network, −Aβ. The minus sign is because the feedback signal is subtracted from the input.