Hi Naazira,
Moreover, A dynamic threshold data receiver uses a single comparator for both squelch and data detection.
It has various advatege over static threshold like:
The comparator has a high-magnitude threshold when the receiver is squelched and a low-magnitude threshold when the receiver is unsquelched.
Preferably the comparator is a differential line receiver, and each of the high and low magnitude thresholds has hysteresis.
he switching threshold is automatically adjusted in response to varying operation conditions such as changes in the received optical signal power. Nonlinear optical thresholding or decision thresholding are used to improve the system
performance and suppress the multiple access interferences in asynchronous
system. Using an encoding/decoding (E/D) technique and
optical thresholding multiple access interference (MAI) can be eliminated
effectively. In on-off keying (OOK) OCDMA, the interference level is
studied to be more and also requires high power level to maintain the desired
BER for the given number of users with direct detection. Even after
employing the optimum fixed decision threshold or adoptively varying the
decision threshold with the number of users, the performance of the
8
asynchronous OOK OCDMA system does not meet performance level of
differential phase shift keying (DPSK) OCDMA. Optical thresholding in
OOK OCDMA can eliminate MAI to the extent as that of DPSK
encoder/decoder in the system without sacrificing the BER and OSNR
required for proper operation of the receiver.
Thanks,