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Receivers
Published in Mike Golio, Commercial Wireless Circuits and Components Handbook, 2018
The bottom end dynamic range of a receiver component cascade is easily described by the noise equations shown in Fig. 1.4. The first three equations for noise factor (fn), noise figure (NF), and noise temperature (Tn) are equivalent expressions to quantify noise. The noise factor is a dimensionless ratio of the input signal-to-noise ratio and the output signal-to-noise ratio. Replacing the signal ratio with gain results in the final form shown. Noise figure is the decibel form of noise factor, in units of dB. Noise temperature is the conversion of noise factor to an equivalent input temperature that will produce the output noise power, expressed in Kelvin. Convention dictates using noise temperature when discussing antennas and noise figure for receivers and associated electronics. By taking the decibel equivalent of the noise factor, the expression for noise out (No) is obtained, where noise in (Ni) is in dBm and noise figure (NF) and gain (G) are in dB. The cascaded noise factor (ft) is found from the sum of the added noise due to each cascaded component divided by the total gain preceding that element. Use the cascaded noise factor (ft) followed by the noise out (No) equation to determine the noise level at each point in the receiver.
Satellite orbital parameters and outline satellite communication principles
Published in L. Tetley, D. Calcutt, Understanding GMDSS, 2012
Because of its effect on the noise levels in a receiver, systems are designed to keep the noise temperature as low as possible. The use of GaAs FET amplifiers, or uncooled parametric amplifiers, allows lower noise temperatures to be achieved. Even better values are obtainable if the front-end amplifier is cooled to keep its physical temperature low; this is possible in large earth stations but is costly and not feasible for mobile earth stations.
Earth Stations
Published in A.F. Inglis, A.C. Luther, Satellite Technology: An Introduction, 1997
The noise temperature, T, is specified in degrees Kelvin (°K), its elevation above absolute zero or −273°C. Thus °K = °C +273°. The noise temperature can indicate either the noise power at a point in the system or the ratio of the noise powers at the output and input of a system component. In either case it is proportional to the noise power, and a low noise temperature is desirable. When applied to a component, the output noise power must be referred to the input, that is, adjusted for the power loss (as in a waveguide) or the power gain (as in an amplifier) of the component.
Development of optimal channel and power allocation through enhanced artificial ecosystem-based optimisation strategy
Published in Journal of Control and Decision, 2022
T. Sarath Babu, Penke Satyanarayana, S. Nagaraja Rao
The interference temperature may get differ when contrasted with noise temperature and it is referred to as ‘the measurement of the interference power and the bandwidth’. Interference is represented in Equation (12). Here, average interference power is indicated as that is calculated in terms of bandwidth and frequency , respectively. The term denotes the temperature noise and refers to the Boltzmann constant 1.38 × 10−23J/l. Interference attained between secondary and primary is not higher than the threshold of interference temperature in the receiver of PU, and also, the Su are didn’t allowed to split its interference constraint and the licensed spectrum is given in Equation (13).
An experimental study on the evaluation of temperature uniformity on the surface of a blackbody using infrared cameras
Published in Quantitative InfraRed Thermography Journal, 2022
S.T. Yoon, J.C. Park, Y.J. Cho
3D noise is evaluated by calculating the deviations in seven cases for the single line, single plane, and space of the x-, y-, and t-axis. This evaluation method is thus more advanced than that of equivalent noise temperature difference. The final deviation for 3D noise is calculated using Equation (6), and the deviation for the line, plane, and space are calculated using Equations (7) through (13). Again, we use the same variables that were used to obtain the equivalent noise temperature difference. An image illustrating the deviation of the line, plane, and space of each axis is shown in Figure 6 [21].
Impact of High-K and Gate-to-Drain Spacing in InGaAs/InAs/InGaAs-based DG-MOS-HEMT for Low-leakage and High-frequency Applications
Published in IETE Journal of Research, 2023
S. Baskaran, R. Saravana Kumar, V. Saminathan, R. Poornachandran, N. Mohan Kumar, V. Janakiraman
Figure 11(a) compares the corresponding minimum noise figure (NFmin in dB) for different Lgd dimensions at Vds = 0.5 V with drain current level of Ids = 5 mA. By reducing Lgd, it can be found that the noise temperature and noise parameters can be improved. As a result, we discovered that a significant reduction in the Lgd will be the most important factor for the InAs DG-HEMT process technique when designing an optimum low-noise HEMTs for MMIC application.