Noise figure i an important parameter in RF receiver design, moriuring how much noise a receir adds to the signol. Understanting real-world exampes helps clearfy how noise figure calculations are applied id in practical practicos.

1. vizsgálat: Calculating Totál Noise Figure

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NF _ totál = NF1 + (NF2 - 1) / G1 + (NF3 - 1) / (G1 * G2)

Converting gains to linear skála:

G1 = 1^ (20 / 10) = 100

G2 = 10 ^ (15 / 10) = 31.62

NF1 = 1^ (2 / 10) = 1,58

NF2 = 1^ (3 / 10) = 2,00

NF3 = 10 ^ (4 / 10) = 2.51

Számológép totál noise figura:

NF _ totál = 1,58 + (2,00 - 1) / 100 + (2,51 - 1) / (100 * 31,62)

Converting back to dB:

NF _ totál _ dB = 10 * log10 (1.5905)

2. vizsgálat: Noise Figure of a Single Amplifier

An RF amplfier has a gain of 30 dB and a noise figure of 1.5 dB. To deterge its linear noise figure:

NF = 10 ^ (1, 5 / 10)

Tiss indicates the amplfier adds approximately 0.5 dB of noise to the input signol.

3. vizsgálat: Impact of Low- Noise Amplifiers

A "needversystem", az "low- noise amplier (LNA) with a noise figure of 0.8 dB and gain of 40 dB is used ad the front end. the provent stages have higher noise norres. The LNA concently reduces the overall noise figure of the system.

Számítástechnikai tha linear noise figure of the LNA:

NF _ LNA = 10 ^ (0,8 / 10)

Mivel ez egy nagy lehetőség, ez az LNA supress the noise concentions of inferent stages, improving overall system performance.