Radio frequency amplifier and error rate

In summary, adding an RF low noise amplifier with a NF of 2.5 dB before a spectrum analyzer significantly improves the error rate, reducing it from 2.1% to 0.7%. This is because without the amplifier, the signal amplitude may be too low for the receiver front end to accurately capture all the data. By amplifying the signal power, the signal becomes stronger and can be detected even with the added noise from the amplifier. Additionally, the order in which amplifiers are placed in a sequence can affect the total noise, so it is important to place the lower-noise amplifier first to achieve the best SNR.
  • #1
thavamaran
42
0
Hi, I am designing an RF link. Before my spectrum analyzer, I have an RF low noise amp with a NF of 2.5 dB. Without this amplifier, my error vector magnitude or error rate is 2.1%, after an amplifier it goes down to 0.7%.

My question is, the receiving signal will have its own SNR and with that SNR I achieve 2.1%, after amplification of the signal power which is relative to SNR, cause the signal will have the same amount of signal power and noise power and amplification will linearly amplify both of these factor.

With taking this into consideration, how can the error rate improve cause the amplification is with respect to signal power and noise power? I can't figure this out, please advice.
 
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  • #2
Simple! Without the amp, even though your SNR is better, but the amplitude is too low, the reciever front end is not sensitive enough to capture all the data.

Think of it this way, if you are driving on a remote road farther and farther from the radio station and you listen to the radio. As you drive farther away, the sound start to break up because the signal is getting weaker and weaker. The detector starting to to fail because the signal level is too low. But if you boost the signal from the antenna, even though you add noise, but the signal is stronger. The extra noise in the signal do not hurt because you can at least detect the signal.
 
  • #3
yungman's right, but I'll throw my wording in, also...

Each amplifier adds some noise. The noise contributed by a given amplifier is, of course, amplified by the following amplification stages. So if you have two amplifiers and one adds less noise than the other, then you should place the lower-noise amplifier earlier in the sequence. If you placed the noisier amplifier first, then its noise gets amplified by the following stage, and you end up with more noise. So swapping the order of the amplifiers doesn't change the total gain of the signal, but it certainly changes the total noise. So you can also add a lower-noise amplifier to the front end of an existing device and increase the final SNR for the same reasons.
 
Last edited:
  • #4
Agree.
 

1. What is a radio frequency amplifier?

A radio frequency amplifier is an electronic device that increases the strength of a radio frequency signal. It is used to boost the signal for better transmission and reception.

2. How does a radio frequency amplifier work?

A radio frequency amplifier works by taking a weak input signal and increasing its power output. This is typically done through a process called amplification, where the signal is boosted through various electronic components within the amplifier.

3. What factors affect the performance of a radio frequency amplifier?

The performance of a radio frequency amplifier can be affected by various factors such as the frequency range, input power, gain, noise figure, and linearity. These factors determine the overall efficiency and accuracy of the amplifier.

4. What is error rate in relation to radio frequency amplifiers?

Error rate, or bit error rate, is a measure of the number of errors in a data transmission system. In the context of radio frequency amplifiers, it refers to the number of errors in the amplified signal compared to the original signal. A lower error rate indicates a more accurate and reliable transmission.

5. How can the error rate of a radio frequency amplifier be minimized?

The error rate of a radio frequency amplifier can be minimized by using high-quality components, proper design and layout, and careful calibration and tuning. Additionally, reducing external interference and maintaining proper power levels can also help improve the error rate of the amplifier.

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