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Any free space laser communicator has to face the issue of attenuation over an air channel as the distance gets larger. By using FSK (frequency shift keying) we can improve that situation. FSK modulation scheme is inherently more resistant to noise than OOK (On Off Keying) which is currently used in optical communication. By implementing FSK in an optical communication system we can get more range than the solutions currently available in the market. In this paper we show how we built an BFSK modulated free space laser-based data transmitter and receiver using cheap readily available components.

With the rapid increase of file size and users, the current wireless data transfer networks are facing massive demands for channels, but if one wants to implement a RF wireless network one must pay a large fee to the government. Free space laser communication has the promise of mitigating some of these demands using line of sight implementations. OOK (On-Off Keying) is the most popular modulation scheme in free space laser communication; however, the loss of a large part of its transmitted power causes low SNR (signal to noise ratio) in this modulation scheme. This is its main drawback, which limits the maximum distance a free space laser communicator can reliably work. FSK (Frequency Shift Keying) has the advantage over OOK in terms of susceptibly to noise. In this paper we will describe the process of making an affordable free space laser communicator using BFSK (Binary FSK) concepts and commercially available off the shelf components. Because we implemented BFKS instead of OOK this communicator is inherently more resistant to noise and other interference.

A comprehensive study was planned to identify best packaging material for the variety “Lady Rosetta” which has a higher market demand. Three different packaging materials (i.e. jute, polypropylene and cotton bags) shown as T1 (control), T2 (Jute packaging), T3 (Polypropylene net bags) and T4 (Cotton packaging) were used. Physico-chemical (weight loss, total soluble solids, pH, starch and sugars) and functional attributes (ascorbic acids and total phenolic contents) were investigated at 15 days interval during storage (25±2oC). The processing performance of stored potato was also assessed in terms of chip crispiness, flavor and color. The physico-chemical parameters investigated revealed an increased weight loss during storage in all samples, however, lower weight loss in polypropylene net bags with a significant difference at P ≤ 0.05. Similarly, total soluble solids increased throughout storage in with a minimum mean value in T3, however a decline observed in pH values with significant difference (P ≤ 0.05). Starch content reduced in the stored samples, while glucose content and total sugars increased significantly (P ≤ 0.05) in all samples. Maximum increase was observed in T1 and minimum in T3. Total phenolic contents showed a slight increase, while ascorbic acid reduced during 105 days storage in all samples. Superior processing results were obtained for the polypropylene stored samples followed by jute and cotton bags. The overall results revealed that polypropylene packaging was found best in maintaining tuber quality attributes up to 105 days during ambient storage. Thus, it is suggested that polypropylene net bags may be used for storage of potato as packaging material. Keywords: Potato; Packaging material; Quality attributes; Storage http://dx.doi.org/10.19045/bspab.2017.60045