Introduction to Cable Communications Systems in Software

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Follow the sine function and confirm the values in Table 8-1 as the angle is increased. Remember that the angle increases counterclockwise ftom what would be the +x-axis.

// Use multiple where clauses. using System; using System.Linq; class TwoWheres { static void Main() { int[] nums = { 1, -2, 3, -3, 0, -8, 12, 19, 6, 9, 10 };

h. In general, the use of several anodes instead of one large anode will tend to provide better distribution of the protective current. Sacri cial anodes may be mounted remotely; the best current distribution will be obtained with the anode(s) positioned to be as equidistant as possible from the metals to be protected. i. Anodes should be faired and, if possible, arranged in a longitudinal row to minimize drag. After installation, peripheral crevices should be sealed. j. Anodes shall be mounted on a sloping surface that cannot entrap gas bubbles. k. If anodes are located near through-hull ttings they shall be positioned forward of discharge ttings and aft of intake ports. Anode locations that disturb the ow of water past the propeller should be avoided. l. All metals which are to receive cathodic protection from the cathodic protection system must have good electrical continuity to the boat bonding system. Galvanic anodes, if used, must be af xed in a manner that electrical continuity is maintained with the metals they are to protect, either through their mounting means or through the boat s bonding system. (1) Propeller shafts do not provide reliable electrical continuity to the boat s bonding system. (2) Rudder posts shall be cathodically bonded by means of a exible conductor positioned to allow full rudder movement without stressing the cathodic bonding conductor or its connection. m. In general, sacri cial anodes may be mounted directly on the metal to be protected, but the best current distribution will be obtained by remote mounting with the anode(s) positioned to be as equidistant as possible from the metals to be protected. n. The negative potential ( 1,050 millivolts as compared to silver-silver chloride reference electrode) that can be achieved by some corrosion control systems will result in some decrease in the effectiveness of antifouling paints. Because the decrease in the effectiveness increases with higher negative voltages, the negative potential should be kept as close to the optimum value as possible. A reference potential reading in excess of 1,100 millivolts indicates excessive cathodic protection. o. Anodes and reference electrodes shall be positioned to avoid contact with lifting slings and chocks when the boat is hauled. p. The electrical interconnection that occurs via shore-power cables or metal mooring cables between two vessels or between a vessel and submerged metal or the dock may result in galvanic corrosion of steel or aluminum hulls and aluminum underwater appendages. An isolator or an isolation transformer can break this couple.

nels unable to be selected by standard TV sets. For some early cable systems that placed added programming channels in the so-called mid-band, a simple UHF up-converter was used. This device simply converted the mid-band channels that were spaced from the FM band to VHF channel 7 to the UHF band (470 to 890 MHz). This block converter, as it was known, connected between the cable and the TV set s UHF terminal, as shown in Figure 2-3. Since there were 9 equivalent 6MHz television channels spaced in the mid-band, these 9 channels, in addition to the 12 VHF channels, resulted in what was known as the 21-channel cable system. At this point in time, available trunk and distribution cables had signi cant loss at UHF frequencies. Available ampli ers had upper frequency limits of 220 to 300 MHz. The reception of UHF broadcast stations was carried on the cable systems by converting each one of them to one of these 9 mid-band cable channels at the headend. The block up-converter at the subscriber s television set would then convert them back from mid-band to UHF. Back in the 1970s the 21-channel cable system offered a decent selection of programming with better reception than most indoor or outdoor antennas. The success of 21-channel systems encouraged the expansion of cable operators to increase the upper frequency limit to 300 MHz. Thus, another 14 television channels were added, making the 35-channel system. This increase in channels beyond the frequency selection capabilities of the TV sets of the day made the tunable, or frequency-agile set top, converter necessary. The method of connecting this device between the cable and the television set is shown in Figure 2-4.

While Java successfully addresses many of the issues surrounding portability in the Internet environment, there are still features that it lacks. One is cross-language interoperability, also called mixed-language programming. This is the ability for the code produced by one language to work easily with the code produced by another. Cross-language interoperability is needed for the creation of large, distributed software systems. It is also desirable for programming