Why is Bit Error Rate (BER) Plotted on a Log Scale?

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Iain Explains Signals, Systems, and Digital Comms

Жыл бұрын

Explains the relationship between BER and the ratio of signal energy and noise energy (Eb/No) in digital communications. Shows an example of BPSK modulation in AWGN channels, and demonstrated that it is a nonlinear relationship involving an integral of an exponential function. This motivates the use of a Log function when plotting BER.
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Full categorised list of all videos with Summary Sheets: iaincollings.com
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Пікірлер: 13

@user-iu7qg9lo7y Жыл бұрын

you channel is a great way to revision heavy courses in a few minutes excellent work, i saw that you made a great video about amplitude modulation, i think you should do the same with frequency modulation

@iain_explains Жыл бұрын

Glad you like the channel. Thanks for the topic suggestion of FM. I've added it to my "to do" list.

@pitmaler4439 Жыл бұрын

Thank you. I just thought about the value -(Eb)^0.5 and (Eb)^0.5. I assume that are voltage values, so it can be -2 V and +2 V. But how do you guarantee thet these values are constant? We transmit with an altenate current, so the value changes over time this way or another. It seems to be a bit confusing. I want to transmit the value -2 V for bit 0, but it changes constantly. Thanks.

@iain_explains Жыл бұрын

Yes, they are voltage values. You might like to watch this video, which answers your question: "What is a Constellation Diagram?" kzfaq.info/get/bejne/ocx6mK9lsbeYY6c.html

@kumudinipatel2565 Жыл бұрын

Sir please explain negative energy concept in signal context. Please

@iain_explains Жыл бұрын

Sorry, but what do you mean by "negative energy"?

@tuongnguyen9391 Жыл бұрын

if it a linear function in the log scale, does that imply that if we increase the Eb/N0 the BER will decrease linearly in the linear scale ? Although this is a stupid question but go back and forth between linear scale and log scale really confuse me ...

@iain_explains Жыл бұрын

Sorry for the confusion, it means log(BER) = - C_1 log(Eb/No) + C_2 . In other words, it is a straight line with a negative slope on the figure where Eb/No is plotted in dB on the horizontal axis, and where the vertical axis plots log(BER) (as shown in the figure on the bottom right hand side in the video).

@iain_explains Жыл бұрын

I've just put the Matlab code for the plots in the video on my website iaincollings.com on the Digital Communications page, under the Modulation and Demodulation tab, in case you'd like to see exactly the equation I implemented.