Anritsu BERTWave Series, Operation Manual, Page: 46 / 466

Chapter 1 Outline
1-20
1.5 Technical Terms
This section explains the technical terms used in this manual.
BER: Bit Error Rate
The Bite Error Rate is the ratio of the total received bits and error bits.
It depends on the SNR (signal to noise ratio).
Signal Amplitude s
Standard Deviation of
Noise Amplitude n
Bit error ratio
Threshold
Figure 1.5-1 Bit Error Rate
When the distribution of the noise voltage amplitude is assumed to follow
a normal distribution, the standard deviation is assumed to be n and the
signal amplitude is s. Bit errors occur when the noise amplitude is larger
than the signal amplitude. Consequently, the probability of amplitude
occurring is the bit error ratio.
The bit error ratio, BER, is calculated by the following formula.
When the SNR is large (greater than 4), the relationship between SNR
and BER becomes linear when plotted on a semi-logarithmic graph.
BER
1
√2𝜋
𝑒𝑥𝑝
𝑥
2
/
𝑑𝑥