## What is noise figure and noise temperature?

The noise figure number, displayed in decibels (dB), represents the performance by which an amplifier or RF receiver can be measured. Noise temperature is a representation of noise in terms of the temperature required to produce an equivalent amount of Johnson-Nyquist Noise.

**How does noise figure change with temperature?**

If you begin with a system at room temperature (290 K) and add a component at the input that itself has a noise temperature of 290 K, the doubling of noise power increases the overall noise figure by 3 dB (2*290-290=290). A 6 dB increase is a 4x increase in noise power (4*290-290=870).

**What does noise figure represent?**

Noise figure is a number by which the noise performance of a radio receiver, amplifier, mixer or other circuit block can be specified. The lower the value of the noise figure, the better the performance. Essentially the noise figure defines the amount of noise an element adds to the overall system.

### What is the formula of noise temperature?

The noise temperature is the temperature of a resistor that has noise power equal to that of the device or circuit. Specifically, the noise temperature is defined by T = N/kB, where N is the noise power within bandwidth B, and k = 1.38 × 10-23J K-1 is Boltzmann’s constant.

**What is the difference between noise figure and noise factor?**

The noise factor is thus the ratio of actual output noise to that which would remain if the device itself did not introduce noise, or the ratio of input SNR to output SNR. The noise figure is simply the noise factor expressed in decibels (dB).

**What is the ideal value of noise figure?**

The Noise Factor of an ideal system is 1. The SNR of the input and output signals of an ideal system are equal. The Noise Factor of a realistic system is always greater than 1. The output SNR of a real system will always be smaller than the input SNR.

## What is the noise temperature of the LNA?

For example, LNAs with a noise figure range of 1.010 to 1.014 (ratio) are more conveniently characterized with a noise temperature range of 3 to 4 kelvins. Thin sheet Kapton at the feedhorn apertures retains the nitrogen pressure in the feedhorns and associated waveguide components.

**What is G T in satellite communication?**

G/T is the figure of merit for a satellite system. G is the Receive antenna gain. T is the system noise temperature. System noise temperature = antenna noise temperature + Receiver noise temperature (LNA) Antenna noise temperature is the noise power seen at the receive output of the antenna. (

**What is ideal and practical value of noise figure?**

A high value of noise figure indicates system degradation and poor performance. A typical RF system with cellular and ISM applications in the operating range of 400 MHz to 1500 MHz has a noise figure in the range of 0.9 dB in the low gain mode and 2.3 dB in the high gain mode.

### What is the power of thermal noise?

Thermal noise power. The noise power in watts defined by the formula N = kTB where N is the noise power in watts, K is Boltzmann’s constant, T is the absolute temperature in degrees Kelvin (e.g., 295 K) and B is the emission bandwidth of the device in hertz.