Detection threshold & receiver sensitivity

[Aabid Baba]

Hello everyone,
I have confusion related to receiver sensitivity and receiver detection threshold. Can we say that both are actually the same or there is a difference between the two. I would appreciate your responses.

Regards
Aabid

[Hamza Ali Abbas Khan]

Hello Aabid.

Talking about receiver sensitivity we know that receivers are integral part of a long distance fiber optic communication system. A receiver includes photodetectors such as Avalanche photodiode, positive-intrinsic-negative semiconductor photodiode etc., demodulators and couplers. Receiver sensitivity is more for an optical receiver when it achieves the same performance with less optical power incident on it. The three important factors which influences receiver sensitivity are bit-error rate (BER), minimum received power and quantum limit of photodetection. Bit-error rate is defined as the probability of incorrect identification of a bit by the decision circuit of the receiver. Minimum received power is a cut-off value below which receiver operation ceases. Use of avalanche photodiode improves receiver sensitivity. But excess noise factor may degrade receiver sensitivity. Quantum limit of photodetection in almost all practical optical receivers is more than 20 dB or exceeds 1000 photons.

I hope this gives you some idea. And i believe both are almost same

[Hamza Ali Abbas Khan]

Hello.

I also want to mention that the receiver in a direct-detection fiber-optic communication system consists of a photodetector followed by electrical amplification and signal-processing circuits intended to recover the communications signal. Receiver sensitivity is defined as the average received optical power needed to achieve a given communication rate and performance. For analog communications, the communication rate is measured by the bandwidth of the electrical signal to be transmitted (B), and performance is given by the signal-to-noise ratio (SNR) of the recovered signal. For digital systems, the communication rate is measured by the bit rate (Rb) and performance is measured by the bit error probability (Pe).
For a constant optical power transmitted, there are fluctuations of the received photocur-rent about the average given by Eq. (11). The principal sources of these fluctuations are signal shot noise (quantum noise resulting from random arrival times of photons at the detector), receiver thermal noise, APD excess noise, and relative intensity noise (RIN) associated with fluctuations in intensity of the source and/or multiple reflections in the fiber medium.
Hope this will be helpful.

Thanks

[Hamza Ali Abbas Khan]

For further info refer to these links.

http://www-ee.stanford.edu/~dabm/186.pdf

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1094177&tag=1

http://www.fiber-optics.info/fiber_optic_glossary/receiver_sensitivity

http://www.electronics.dit.ie/staff/ysemenova/OCS/Optical%20Receivers.pdf

https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact

[Aabid Baba]

Hello Hamza Ali Abbas,
Thank you fro sharing some valuable information.
I somehow was able to relate that the receiver sensitivity and the detection threshold for the receiver are same. Because receiver sensitivity is the minimum received power for the receiver to to detect the sent bit stream and the detection threshold is almost the same. Actually it is a secondary term for receiver sensitivity.
Anyway thanks for sharing the links too. Some were helpful.

Regards

[umer ashraf wani]

Receiver threshold is user defined while receiver sensitivity is inherent

[Aabid Baba]

Hello Umer,

I am stuck here. Can you please tell Where do we set the threshold for the receiver?
I would appreciate that. Thanking you.

Regards

[burhan num mina llah]

Hello Aabid,

In my opinion both receiver sensitivity and the detection threshold are closely related because if we see receiver sensitivity is defined as the minimum average power to detect a signal and on the other hand the detection threshold is also the minimum average power to detect a signal received by the receiver.
I guess these are related terms. I hope this will help you.

Regards

Burhan

[Karan Ahuja]

Hi.
I agree with Burhan. He is right, In my opinion too receiver sensitivity & detection threshold mean the same thing.
The definition given by Burhan in the above reply should clear the air here.
Hope this will help in removing the doubt.
Thanks
Regards

[Aabid Baba]

Hello everyone,

Thank you for your responses. I appreciate your efforts. One thing is very clear that both are related in some or the other way. As put correctly by Burhan , the definitions are very much related and it can be concluded that both are near about the same thing. Anyway thank you all.
Regards

[burhan num mina llah]

Hello Aabid Baba

You are welcome. I hope you would have gotten some idea about the two factors.

Regards

Burhan

[Hamza Ali Abbas Khan]

Hello
Thank you everyone for sharing this information. I agree with most of the replies.
Thanks
Regards

[Aabid Baba]

Hi All,
Thank you for your valuable efforts. I appreciate your efforts. It has been very helpful.
Regards

[Aabid Baba]

Hello Everyone,
Thank you so much for the concern. I appreciate your efforts but please try to make it more of a discussion rather than copying and pasting the same stuff.
Regards

[Author]

Posts